1978 US Army Terrain analysis, part 1 36p.pdf

8/14/2019 1978 US Army Terrain analysis, part 1 36p.pdf

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TERRAIN

HE DQU RTERSDEP RTMENTOFTHE RMY MAY 1978

WWW.SURVIVALEBOOKS.COM


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Theword "he"or "his" inthispublication isintendedto includeboththemasculineandfemininegendersandanyexceptiontothiswill besonoted.



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FM 21 33HEADQUARTERSFIELD MANUAL DEPARTMENT OF THE ARMYNo. 21 -33 Washington, DC, 15 May 1978

TERRAIN ANALYSISTABLEOFCONTENTS

C H A P T E R 1. INTRODUCTION

CHAPTER 2. COLLECT DA TAKindsof DataWheretoGetIt

CHAPTER 3. MANA GE THE FILE OF DATAFile PhotosFileMapsPlot Remotely Sensed Imagery

CHAPTER 4. USE THE DATA FIL EAnalyzeSourceMapsInterpret ImageryInterpret Written Information

CHAPTER 5. AN ALY ZE TERRAIN FACTORSPrepare Climatic Summ ariesAnalyzeD rainage FeaturesAnalyzeSurface ConfigurationAnalyzeGeologyandSoils

Section

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2 - 12-12-5

3 - 11 322 3-43 3-7

4 -11 4-12 4-113 4-13

5 - 11 5-12 5-43 5-154 528



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Analyze VegetationAnalyze BeachesandO ther Coastal FeaturesAnalyze Manmade Features

CHAPTER 6. PRE PARE SP EC IA L PURPO SE M AP SPrepare Cross-Country Movem ent (CCM)MapsPrepare Linesof Com munication (LOC)MapsPrepareZonesofEntry(ZOE)MapsPrepare Coverand Concealm ent (C&C)MapsPrepareObservationandFieldsofFireMapsPrepareTerrainMaskingandNapoftheEarthMapsPrepareOtherSpecialPurposeMaps

CHAPTER7. PREPARE AND DISTRIBUTE TERRAIN STUDIESWriteText for Terrain StudiesReproduceTerrainStudiesDisseminate Terrain Studies

APPENDIX REFERENCES

Section Page

5 5-406 5-487 5-56

6 - 11 6-42 6-73 6-84 6-85 6-106 6-107 6-12

7 - 11 7-22 7-33 7-3

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CHAPTER 1

INTRODUCTION

PURPOSEThismanual is intendedtoassist youiniden tify ing the dut ies of a Terra in Analyst,and t o serve as a reference w hen yo u areperformingsuchduties.SCOPEAND RELAT IONTO OTHERMANUALSYou will find here the p rocedures tha ta re fo llowed in perfo rming the tasks tha t a Terrain Analyst is expected to be able to do.This m anu al doesnot repeat procedures tha tare explained in other manuals or in coursest ha t sh ou ld b e c om ple te d b efore y ou e nte rthe Ter ra in Analyst course, bu t it te lls you w here t o find such in form ation w hen y ouneed it. If you have the right referencemate ria ls you can read ily find the answers to quest ions of technique and procedure thatmay arise in your s tudy and work. A lis t ofmanuals that areuseful for aTerrain Analystisfound inthe Appendix.CHANGESAND COMMENTSThe Army would like to have yourcomments and recommendations for improving this p ublication . Use DA Form 2028(Rec om m en de d Changes t o P ub lic atio ns ),giving the specific page, paragraph, and l ineof th e t ex t for w hich t he ch ange is recom mended and reasons forth eproposed change.DA Form 2028 should be sen t d ir ec t t o theCommandant , U .S . Army Eng ineer Schoo l,FortBelvoir,VA22060.WHATISTERRAIN ANALYSISTerrain Analysis istheprocessof analyzingageographical areato determ ine the effectof the natural and m anm ade features onmilita ry operat ions. The p roduc t of te rr ain analysis is a ter ra in s tudy, which is one of a n um be r of sources of inform atio n (m aps,photographs, in terrogation, e tc .) on which a commandercanbasehisdecisions.

T errain is defined as a p or tio n of t heearth 's surface, including m anm ade andn atu ral features. T errain d ata (or terraininformation) arerawdata inanyform about asegmentof terrain. Whenthesedatahavebeene va lu ated , an alyzed , i nte rp re te d, a nd in te g rate d, they bec om e terrain in tellig ence,which may be presented in a num ber ofd iffe rent formats , one of which is a te rra in study.

Terrain intelligence isthus oneaspectofoperational intelligence. As an enlistedter ra in analyst , your duties will most likely be to produce ter ra in in te lligence for use a tthe tactical level of operat ions. Operationalintelligence,how ever, is required at alllevels,so y o ur p ro du ct m ay be used e ith er b y t hec om m an de r of th e o rg an iz atio n y ou are inorbyhigherheadquarters.LEVELSOFPROFICIENCY INTERRA INANALYSIS

A beginning terrain analyst will n o tusually be called on t o prepare detailedte rra in s tudies, bu t he should know how togo a bo ut it in o rd er t o develop increasedproficiency w ith e xp erie nc e. O rd in arily , abeginner (grade E5) will be required toe xtra ct basic facts from his d ata sourcesand present them on factor overlays. A tth e n ex t level (E 6) he should be able toin te rp re t th ese facts in te rm s of m ilitarya ctiv ities and t o c om bin e th e in fo rm atio nfrom several factor overlays in order t oanswer specific questions. A t th e seniorlevel (E 7) he should be able to supervisethe work of several analysts, to prepare morecomplex te rr ain s tudies, and to p redic t t heperfo rmance of various types of equipmentunder the p revailing cond it ions of weatherandseason.

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THEINTELLIGENCE CYCLESince intelligence may beuselessorevendangerous unless kept up-to-date, i ts production and rev ision must never end . This cont inuing activi ty is carried on through a four-s tep cyc le called the in te lligence cyc le : (1 )plan to collect data, (2)collect required data,(3) process col lected data into intel ligence,(4 ) d isseminate the in te lligence . Deta ils ofthese four steps will bedescribed in the restof th is manual. It is ca lled a cyc le because after you complete the four s teps, you begin overtokeepyourintelligenceup-to-date.SKILLSYOUWILLNEEDTo be a terrain analyst you m ust beth oro ug hly pro fic ien t in to po grap hic m apanalysis, and m ap in te rp re ta tio n. A lm ostas important are skills in interpret ing photographic and other remotely sensed imagery .These skills include the use of formulas andmeasuring t echn iques , bo th on photographs and maps and on the ground. You alsoshould know how to docartographic draf tingand should be able to w rite clear, factualreports.

Before starting th e Terrain A nalystC ourse y ou should have eith er courses orpractical experience in Soils Analysis, ImageInterpretation, and/orMapC ompilation.

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H PTER 2

COLLECT DATA

SECTION 1. KINDS OF DATAAs a terrain analyst you are responsiblefor ana lyzing da ta that come to you from a variety of sources. Part of y ou r jo b is tocollect t he da ta yourself. You shou ld know

something about the sources of informationin order to beabletorequest itwhen needed,and y ou should know th e advantages anddisadvantagesofeach kind.Your three main sources will be photog ra ph s, m ap s, an d w ritte n re po rts . In th ischapter we will consider what kind of inform ation you can get from each of thesesources , and where you can get them. Theremay be t imes when you will have to depend

on your own resourcefulness to get the data that youneed,but normally your detachmentcommanderwillorderitforyouprovidedyoucantellhimaccuratelywhatyouneed.REMOTESENSINGMuch of the data that you willbecalledon t o analyze will be obtained by aerialre co nn ais sa nc e. T hese d ata u sually are inthe form of photographs, but in recentyears o ther methods have been devised for"remote sensing."Therefore weusethe moregeneral term imagery when talking about theresu lts of aerial reconnaissance. There are many different kinds of imagery inusetodayand o th ers u nd er e xp erim en ta tio n. T hosediscussed below are the p rincipal ones thatyou should knowsomething about.

PHOTOGRAPHIC IMAGERY(1) PanchromaticPanchromatic pho tography is in b lack and w hite, b ut th e film is sensitive to allvisible wavelengths. Thismeansthat allcolors

will regis ter on the film, and differences in to ne on th e p ho to gra ph will vary w ith th eintensity of the object's color rather than i tswavelength. All black and white film used inaerial photography is panchromatic. Despitethe m any new films and techniq ues th athave been developed, b lack and white panchromat ic is still t he most fr equently used film.

(2) Infrared PanchromaticInfrared black and white film issensitiveto b lue-viole t and infrared light. I t is sometimes exposed th rough red filte rs ; t hen the exposures are made byredandinfrared wavelengths only and called "near- infrared." Thistype of film is used most ly for detection ofdifferent types of vegetation or plant disease.The Army uses i t for detec ting camouflage because i t enables an interpreter to te ll cutfrom live v eg eta tio n, and v eg etatio n from artificial m aterial such as n ets and p ain t.

(3) InfraredColorThis film, originally designed by Kodakas Ektachrome infrared aero film, is a false-color, reversal film used forcamouflage detec

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t ion. I t showscolorsthat arefalse for natural featu res. Na tu ra l dec iduous foliage appears red and p ain te d artificial foliage app earspurple. This film isalso used fordetection ofp lant d isease , insect i nfest at ion, and wate rpollution.

(4) ConventionalColorThis film, although expensive and morecri tical to expose and process, is valuable foridenti fy ing soil types , rock outcrops, industrial stockpiles, subsurface water , and shorel ines. I t is rarely used under field conditions.(5) MultibandMu ltib an d p ho to gra ph y is still in th eexperim ental stage.Specialcamerashavebeenbuilt using many lenses (up to 9) at the samet ime , each with a film of d iffe rent spectra lsensi tivi ty . The camera photographs an areawith all these films andlenses simultaneously.Each film records different data aboutdifferent objects because each object ref lectsdifferent spectral energy. These objects

WIDTH OFTHE SCAN

(terrain features) can now be d ete cte d asdifferent tones of gray on the differentfilms, whereas they may appear the same onone type of film. Fur ther research is neededbefo re multiband will be operat ional underfield cond itions.NONPHOTOGRAPHIC IMAGERY

(1) ThermalInfrared"T herm al" m eans having t o do w ithheat . Accord ingly , thermal in fra red r ecords th e heat of terrain features. A bare rocksurface ishotter in the bright sun than greengrass. T herm al infrared p ho to gra ph s th ehotte r feature asbrighter. Thisinfrared imageis a photograph of an image that appears onan electronic tube something like a televisiontube. This tube and the to ta l infrared sensorsystem areinan airplane.Th esensor scansthete rr ain by swinging from side to side as theairplanefliesahead.

TERRAINCOVEREDBY THESCANNEDIMAGERY

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The scanner , t he re fore , "pa in t s" the groundin n arro w strip s. These strip s are p ho to graphed all toge ther to make an image like a photo from a s tr ip camera . The imagery canb e used t o d ete ct fire w hen co ncealed bysmoke, as in a fores t fire . I t has many otherpotent ial uses, such asmapping seismic faultl ines, identifying minerals, crop diseases, soil moisture content, cool underground spr ings ,and heat from vehicles.Mostmilitary usesareclassified.

: ' "

(2) RadarRadar imagery, particularly Side-lookingAirborne Radar (SLAR), is similar to thermalinfrared in many respects. The radar " look s" out from each sideofthe airplanein anarrowbeam. Then the a irplane flies ahead, and therad ar ta ke s a no th er lo ok sidew ays. T hese" lo o ks " (or side scans) are added to each other on the radar di splay tube . Apicture is ta ke n of th is tube and th is p ic tu re is yourSLA R im agery . A gain, like IR , t he te rra in covered is in a strip like t he phot o from astripcamera.

Side-looking Airborne Radar (SLAR) Images

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(3) SatelliteTransmittedPhotos of th e earth are transm ittedfrom sate llite s. These a re no t d ir ec t pho tosb ut are p ho to s of a c ath od e ray tu be , likea television screen. T he satellite c on ta in sa video tape recorder likeatelevision camera.W hen t he c am era is tu rn ed on a p h ot o of aport ion of the ear th is made on v ideo t ape .T his v id eo ta pe is tr an sm itte d t o th e e arth a nd r ec on sti tu te d on a TV t yp e screen an dphotographed.

MAPSA topograph ic map is t he most important tool of aterrain analyst. You will seeinchap te r 5 howyou can use " to po " maps forana lyzing d ra inage, s lope , sett lement s, and many other aspects of ter ra in . So i t' s importa n t t o have to po gra ph ic m aps th at are asrecentandaccurateasyoucanget.

T he re are also o th er k in ds of m ap s. A p la nim etric m ap is o ne t h at d oe s n o t sh ow relief. They are used especia lly for mappingmanmade features such asci ty streets, wherei t is important toshowalot of detai l withoutthe"clut ter"of contour l ines.

Another kind of map iscalled thematic.These are maps that aredesigned to showjuston e featu re or " th e m e ," so th ey are oftencalled special purpose maps. Examples wouldbe maps of average ra infall, location of certain minerals, and distribution of population.The factor overlays that you will be making(see chap te r 5) a re a k ind of themati c map .

TEXTThe third major sourceofdataisword s-p rin te d, t yp e d, w ritte n or spo ke n. P rin ted

words (or text) that are availableto everyoneare called "open l i tera ture ." This i s the k indof mate ria l t ha t you can get from a l ib ra ry ,bookstore, ormagazinestand.Theterm refersespecially to scholarly writ ing such as booksand art icles in recognized journals. The openliteratu re of geography co ntain s a lo t ofinform ation that is valuable for terrainanalysis because i t is carefully done, usuallywellil lustrated,andeasyto obtain.

There are a lso many other k inds of textt ha t can be useful t o y o u. T ravel a cc ou nt s,guidebooks, industr ial advertising, and chamber of commerce publications can all tell yousomething about an area. Youcaneven learna good deal about local businessand industryfrom atelephone directory.

Mili tary intel ligence reports are another essential source ofinformation, but they haveto behandledm orecarefully than openliterature because they are usually classified. Theirscopevaries from an entire coun try, asintheNIS (National Intelligence Surveys) producedin Washington, to special intel ligence reportsof a local a rea which would be typed in thefieldwithjustafewcarboncopies.

A good source of d ata , although n otalw ays reliab le, is go vernm en t re po rts ofvarious k in ds. M ost go vernm ents p ub lishstat ist ics on cl imate, streamflow, populat ion,agricultu ra l p roduce , industr ia l p roduc tion,and avariety of othersubjects.Keepinm ind,however, that in some countries these f iguresm ay be " sl an te d" t o s up po rt som e governmental policy , while in o thers i t s imply mayn o t be p ossib le t o get re liab le figu res. F ore xam ple, w here a p op ula tio n lives m ainlyby subsis tence farming, most of the producemay never be so ld and so no r ecord of i t is made.

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SECTION 2 . WHERE TO GET ITMILITARY INTELLIGENCE SOURCESIn the field your f irst source for data ismili tary intell igence. I t is Mi 's job to get andprocess the data that you will use in ter ra in analysis, especially data from aerialreconnaissance. When you need photos or otherim agery of a c erta in area, y ou can re qu es tth em from MIBARS (Military In te llig en ceBa tta lio n, A erial Reco nna issan ce and Surveil lance) . If you are a ttached to a d iv is ionheadquarters, you should have close relationswi th the d iv is ion MI company. Requests ford ata should go through y ou r d eta ch men tcommander.AERIAL PHOTO AGENCIESIn addi tion to the imagery that you canget from MIBARS, there are many sourcesofaerial photography that can beusedinpeacet im e . T he U .S . D e pa rt m en t of A gric ultu rem ain tain s a library of aerial p ho to grap hscovering m ost of th e U nited States from which photos canbe ordered:

Western AerialPhotography Labo ratoryAdministrativeServicesDivisionASCS-USDA2505Parley'sWaySaltLake City,Utah 84109You can obtain a map showing the"Sta tus of Aeria l Photography in the UnitedStates"bywritingto:

NationalC artographic Information CenterUSGSNational Center12201SunriseValleyDriveReston,Virginia22092This map shows areas that have been photog rap he d e ith er by g ov ern me nt agencies orcommerc ia l firms, and te lls where you canobtainprints.

Most of t he s ta te s also have agencies

t h at m ain ta in p h ot o lib ra rie s. All of th esesources make a charge for furnishing photographs.A ir p h oto s are available for p urc ha sefrom commerc ia l aerial survey firms in the United Sta tes and some other countries . Thecost is often higher than that of photos fromgov ernm ent agencies, b ut th e p ho to s m ayhave larger scales than are o therwise available. Some of these companies are l is ted in the USGSm ap described above, while othersare given regularly in th e jo urn al " Ph o to grammetric EngineeringandR.emote Sensing."MAPPINGAGENCIESMaps forthe U.S.Army areproduced bythe Topographic Center of the DefenseMapping A gency (D MA ). O th er m ajor elements of DMA are the Hydrographic Center ,which mainly produces char ts for the Navy,and the Aerospace Center, whichisconcernedwith aeronautical and spacenavigation charts.So most of the mapsyou will be using comefrom t he D MA TC. T o o bta in all n ecessaryinformation about maps of the world,r equest a copy of "Departmen t of Defense,DMA Catalog of Maps, Charts, and RelatedProducts"from:Defense MappingAgency Topographic CenterWashington,D.C. 20315This very extens ive cata log is pub lished in four parts. Part 3, Topographic Products,hassix volumes, each dealing with a port ion of t he w orld . It c on ta in s in de xes of all DMAm aps and o th er p ro du ct s availab le. It also c on ta in s in stru ctio ns o n h ow and w here to order maps and products , for example , aerospace, h yd ro gra ph ic , to po grap hic and airtarget material products, city maps,trig lists,map gazetteers, and digital topographic data. Since the names and locat ions of map depotschange from timeto time,up-to-date orderinginform ation should be o btain ed from th eaboveaddress.

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Nearly all foreign governm ents alsomainta in one or more mapping agencies.Although DMATC maps cover all par ts of thew o rld , y ou m ay be ab le to get m ore u p-to date mapsthrough local sourceswhen you areoverseas. The Library of Congressmaintainsalis t of these sources , "Published Sources of Information about Maps,"and "Selected ListofMapPublishersandSellers,"whichyoucanobtain from the Geography and MapDivision,Library of Congress,Washington,D.C.205 40.

In additio n to DM A, th ere are m anyother government agencies, both in theUnited States and abroad, that producemaps.Usually these maps are for special purposes.For example, the U.S. Forest Service and its c ou nt er pa rt s in o th er c ou ntrie s issue m ap sshow ing cover ty pe and o th er aspects offorest s tands. Some of these are very usefulin ter ra in analysis . You can also get governm e nt m ap s sho win g t ra nspo rta tio n ro ute s,mining activity, recreat ional areas, and otherinformation about the ter ra in . Some governm e nts p u t o u t m aps show in g ty pe s of lan duse.

Private mapping agencies are also activein so me c ou ntrie s. All E uro pe an c ou ntrie sare covered by road mapsthat aredistributed(for a sm all charge) by gasoline v end ors.Au tomobi le c lubs a re active in many countrie s and so me of th em p ro du ce good ro admaps . The maps tha t a re sold in bookstores f requen tly give deta iled in fo rmation abou tcitystreetpatterns.WRITTEN MATERIALAgoodplacetostart getting informationabout an area is the local l ibrary , e ither in a town or on an Army post. Youwill probably find trave l accoun ts and perhaps sc ien tific w o rk s a bo u t t h e c o un tr y, s ta te , or lo ca lity you areconcerned with.

Geographical publications are especiallyuse fu l. Some of the lead ing ones wr it ten in Englishare:

NationalGeographicMagazine(the well-known magazine published inW ashington, D . C , w ith ex ce llen t illustrations and frequent map supplements)The Geographical Review(a sch olarly jo urn al p ro du ce d q ua rte rly by the American Geograph ical Society, Broadway at 156th St ., New York, NY10032)The Geograph ical Magazine (an i ll us tr atedmonth ly with a rtic les by specia lis ts for thegeneral re ad er, p ub lish ed by N ew S cience P ub lication s, 12 8 L ong A cre, L on do n WC 2E9QH,England)SOURCESOFCLIMATIC DATAFortunately there isno lack of goodclimatic data for most of your needs. The U.S.Government and most fo reign governmentshave extensivedatacollectionand summarizat ion programs. Weather data are widely d isseminated and are seldom if ever c lass ified. Cooperation and exchange of weather information and data are normally restricted onlyinwartime.

The Air Weather Service (AWS) of theU.S. Air Force has the responsibi li ty of providing you w ith any and all d ata y ou willr equi re -both s ta teside through the Env ironmentalTechnicalApplicationsCenter(ETAC)and overseas th ro ug h t he W ea th er W ing o rd eta ch me nt in y ou r th ea te r of o pe ra tio ns .(See sec tions 2-19 and 2-20 of FM 30-10.)Req ue sts for E TA C's sup po rt are m ad e b ystan da rd m ilitary le tte r and addressed t o :USAF ETAC, Scot t AFB, IL 62225 . A concise s ta te me nt of th e p ro blem in te rm s ofeith er th e e nv iro nm en ta l factors involvedor of the c limatological informat ion desired is all t ha t is needed. If t he p rob lem canno tbe adequately defined ortherequest properlystated, then Air WeatherServicestaff meteoro logis ts are availab le to assis t. The r eques tmust s ta te the da te the solu tion o r in fo rmation isneeded andthepriorityof the programo r p ro je ct re qu irin g sup po rt. A staff m e te

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oro logis t can be contac ted by phone befo re wr it ing the formal let ter. Remember that the Air Weather Serv ice does have the missionto supply Army elements with c limatic data andevenanalysis.Probably amajori ty of thedatayou will re qu ire for y o ur s tu die s and clim atic sum maries a lready exis ts in published form andin the open l i terature. I t will befound inanygood library in your area of operationsin official government pub li ca tions. It willalso occur in a wide varie ty of c limatic andgeographical te xtb oo ks and even in som etravel guides. It isgood practice to get started

looking for m aterials for your clim aticsummary or study while waitingfor officiallyresponsible agencies to supply you with whatyou need. Contact your local NationalWeather Service office or U.S. Air Weather Service officer and see what they might haveon hand that theycouldlendor supply. Thentr y large p ub lic or u niv ersity libraries foradd itional sources , and consider the possib il ity that what you need may already exis tin an appropr ia te published form so that allyouneedtodoiscopyit .*

F or som e foreign c ou ntrie s and areasremember that agreater concern for weather

See especially section23 of the National IntelligenceSurveys NIS), completed for m ost countries of theworld. Theseclimatic sections do not get out ofdate.

FM 21-33

da ta may rest with an agency out side of the meteorological service of that country , suchas a hydrological ( ir rigation/f lood warning)se rv ice, an agricultu ra l bureau, o r even an association of airlines at som e m ajor airport. Unusual sources of goodd atacan sometim es be fo un d, such as re co rd s at a re so rthote l , a marina, a TV sta tion, or a mine a t a lonely location.Another source of da ta which requ iresmore experience to use iscloud photographyand other types of imagery taken from satell ites by the Defense Meteorological Satell iteProgram (DMSP) for use of mili tary person

nel. Global DMSPdata are received andprocessed at th e Air Force Global W eatherCentral(AFGWC),Offutt AFB ,N ebraska.Conventional weather maps produced inth e m ajor c ap ita ls of th e w orld , and riverstage data taken a t various gaging s ta tionson a stream , are o ther sources of usabledata . Governments below the national levelalso ta ke and k eep w ea th er d a ta -a lt ho u gh these are generally for special studies and are

of shorter durations. I t is a good ru le neverto tak e " no data available" as an answ erwith out diggingjust alittleb it further.

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CHAPTER 3

MANAGE THE FILE OF DATA

After youcollecttheinformation (data), you need aplace to store i t and youmustbeable to find i t when you need it . No ma t te rhow impressive the da ta may be , i t' s worthless if you put i t somewhere and can' t find i tor can 't tel l what i t is when you do. Soyoumust file i t, label i t, and be ab le to find i tagain and recognize it. Keep y ou r filingm eth od sim ple enough t ha t it w ork s. T hevery sophis tica ted sys tems for t it ling, plott ing, and handling photography described inTM 30-245, Image Interpretation Handbook,maynotbesuitableforfieldconditions.

So : 1. K EEP IT SIM PLE KNOWWHEREIT IS3 KNOWWHATIT IS

Almost all datay ou collectwillbeintheform of p ho to s, m aps, or d ocu men ts andbooks , occasionally supp lem en ted by non-photographic remotely sensed imagery. Thedata is s tored and retrieved either (1) manually (by h and ), (2) by autom ation usingmachines to do part of the job and manuallyto t ake ca re of the rema inde r of the job , o r(3) by automation using machines to do allofthejob.

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SECTION 1 . FILE PHOTOST he sim plest ways to manage1 aeria lphoto files are wi th e ither photo indexes or

map overlay plots. Titles are important onall three- the photos, the indexes, and the p lo ts .P ho to In de x Mosaic. An u nc on tro lle dpho to index mosaicisthefastest waytoshowpho to coverage p rovid ing you have a copy

cam era available.Y ou lay t he p h ot o p ri nt sfrom each flight line over each o th er bymatching detai l. Staple them in place. Add atitle and a legend and draw t he m ap areac orn er tic ks . (See TM 3 0- 24 5 , page 5 -16 ).Have it " sh ot" and reduced on th e copycamera. If no copy camera isavailable, makeanindexplotofthephotos.

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Index plot of Photographs. Drawing de- "(12) Longitude of the airplane (when theta ils on p lo ts is t ime-consuming, so be sure photowastaken)y ou have enough tim e t o draw th e detailsyou need. Use a plo tting tem pla te on ano ve rla y, over a m a p, usually a 1 :2 50 ,0 00 ,and draw the outl ine of the area covered onthe map by the photo. (See TM30-245,page5-16.). Ifflight linesareregular,you may plotonly every fifth pho to,aswellasthe first andlast photos of the flight line.For examplesofplots of oblique,strip,and panoramicp hotos,seeTM30-245,pages5-17and5-23.

TitlesofPhotos.Therearemanysystemsof standarized titling. (See TM 30-245,chapter 4.).Some titles arebrief andsomearedetailed.The title is exposed directly onthe film,in the corner ofeachfilm frame, asthe photoistaken . It appears as asmallrectangular boxo r " b lo c k" . T his b lo ck c on ta in s th re e columns of dots which are inbinary code.Whentranslated by means of acomputer , the codete lls t he following in fo rmation abou t each photo frame:(1) Date (of photo)(2)Photo-takingunit(3)Sortienumber(4)Cameratype,orsensor(5)Barometricaltitude(6)Headingoftheairplane(7) Drift(8)Roll(9)Pitch(10)Time(GMT)(11) Lati tude of the a irplane (when thephotowastaken)

(13) Radar altitude(14) B/N (bombadier /navigator mode of operation)(15) SLAR (side-looking airborne radar)mode(16) ELRAC (electronic reconnaissanceaccessoryset)

O th er p ho to titling m e th od s, such asa lphanumeric da ta b locks, are d iscussed in TM30-245.Should you acquire p hoto s with notitles, you will have to t it le them manually .On the film leader,writethename ofth e areacoveredbythephotos.Theminimumtowriteoneach film frame orprint istheroll num ber,date, and the frame number . Addit ional data may be written elsewhere,such asonthe filmroll can , the package of pr in ts, or the photo datacard.P ho to D ata File Cards. If y ou a re r equired t o store a large a mo un t of p ho to graphy and sensor imagery , you may have touse acard fileto control orsearch for photo s.Depending upon the size of your collect ion of photos and sensor imagery , you mayneed a crossreference file on 3x5cards. Forexample , suppose a reques t is , "What is allthe lates t coverage you have over Tan An?" T hen y ou need a file by d ate of coverageand by the area of Tan An. O ther crossreferences can be by c ou ntry , province,source,typeofimagery,orscale.

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SECTION 2. FILE MAPSMap In de xe s. T he in dex es of foreignmaps that you will use most frequen tly are

those by the Defense Mapping AgencyT opographic C enter (DM ATC), form erlyknown as Army Map Service and later as theArmy Topographic Command (TOPOCOM).Thesearedescribed inTM 5-248.DMATC maps,however, do not providec om ple te coverage, especially w ithin th eU nited S tates, Puerto R ico, and th e U.S.terr i tor ies. DMATC is responsible primarilyfor foreign m ap s, and t he U .S . G eological

Survey (USGS) is responsib le for domes tic maps. (See chapter 2.) So you will need

USGS mapsfor complete United Statescoverage. The USGS maps are indexed by adifferent system than those of DM ATC.USGS indexes maps by standard quadranglesof 7-1/2 m in utes , published at a scale of1:24,000, and by 15 m in ute s, a t a scale of1:62,500 or 1 inch to them i le .* MostUSGSmaps of the U.S. arepublished atthose scalesin a dd itio n t o 1:250,000 and 1 :1 ,0 00 ,0 00 .A laska is published only at 1:63,360 and1:2 50 ,0 00 . P ue rto R ico is publish ed onlyat 1:20,000, 1:120,000, and 1:240,000.

1 Inch to the mile is actually 1:63 360 butthe difference is neg ligible at this scale.DMA MAP C A T AL O G - PA R T 3

TnCiderThisIndeiSTOCKNO TSC5XD34EI20376

LEGENDMaps Available OnlyWhere EditionNoandTinting a reShownf lt he lMap Ednon No Map Ed it on No

Oenoiesnew 01revised mapsshown lor[helusttimeonthisindex

ORDER BY S TOCK NUMBERTheSTOCK NUMBER iscomposed ol15

ssalpha/numeric unitswhich, inse;r!. identity thesenesandsheetnum

The SERIES number isihe 4or5 unitalpha/numenc idenut ication shown in theappropriate 3ieaon thelaceol thisindexWhen iheseriesconsists ol 4 units a n X isaddedasthehlih unitThe SHEET number consists ol 10oilessingwithihe sixttiunit otihestocknumberAnyRoman numerals areconvertedtoArabic n um beis 8 . I 10 I . II to 2 . a leWhetsthesheetnumber requiteslessthan10 un it s, unused un it s a ic l el t b lankWhere nonstandard sheet numbers ateused i pl er i n t ne sample s tock number

Delaware V 732Maryland V 733New Jersey V 722North Carol ina V742 Pennsylvania V 73 1Virginia V734W est Virg inia V 7 5 4

Vol V Sec 2 Aug7634E 123-4



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USGS indexes are by state and eachq ua dran gle h as a n am e , n ot a n um b er likeDMATC maps. The name isusually aprominent feature such as the largest c ity or townin the quadrangle, and the names of adjacentsheets are shown in the marg ins. You musthave an index to know the names of USGSsheets that arem ore than one sheet removedfrom thesheetyou have.

NATIONA L TOPOGRAPHIC MAPS

Series

7&-minutePuerto Rico 7^-minute. . .15-minute . .Alaska 1:63,360U.S. 1:250,000.U.S. 1:1,000,000

Scale 1inchrepresents

1:24,000 2,000 feet1:20,000 about 1,667 feet1:62,500 nearly 1mile1:63,360 1mile1:25O,OOO nearly4miles1:1,000,000 nearly 16miles

Standardquadranglesize(latitude-longitude)

lxh x A m in . 7*4x 7V4min.15 x1 5 m in .15 x 2 0 to 36min.3 l x 2 3 4 x 6

Quadrangle Papersizearea E-W N-S(square m iles) w idth l ength (inches)49to70 ' 2 2 x 2 7 71 29V4x 27lA197to282 ' 1 7 x 2 1207to281 2 1 8 x 214,580to8669 4 3 4 x 2 273,331 to102,759 2 7 x 2 7

1South o flatitude 3 1 7&-minute sheets are 2 3x27 inches; 15-minute sheets a r e 1 8 x 2 1 i nches .2Southo f latitude 62sheetsare 17 x 21 inches.3MapsofAlaskaa nd Hawaii vary from these standards.4Northo f latitude 42sheets are29 x 22 inches. Alaskasheetsare30x23inches.

The only other index ofcomplete worldmap coverage is the U.S.Coast and GeodeticSurvey 's index of aeronau tical chart s. (See chap te r 2 .) These indexes are numbered bya sti ll different system from that of USGSorDMAT C.T he charts canserveasauseful baseuponwhichtoplotothermapstoshowcoverage, especially of foreign maps (published byforeign nations ).

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MapPlots.Mapsareeasytoplot.Simplyd raw the outl ine of the map coord inates ona smaller scale map oronanindex of anothermap series. You can use an overlay to avoid m ark ing u p a base m ap or th e in de x. M apoverlay plots are agood way to compare thecoverage of different maps of the same area.MapTitles and Files. If mapswhich you

arefilingdonothaveatitleinthelowerright-hand corner, you may need to write one in order to find iteasilywhensearchingthemapfile. Maps are best filed in fo lders of s trong(wrapp ing type) paper 24" x 36". They can be easily and quickly made in the field with masking tape or s taples , and can hold 30 ormoremaps.A title of thecontentsshould bew rittenon the lower (front) right-hand corner.These

fo lders can be numbered in o rder to r eturnthem to their proper place inthef ile.Agoodidea is t o include a second copy o f the mapindex in each fo lder to indicate i ts contents .Keep the master copy of all indexes togetherinabinder.Maps can be grouped in folders regionally by countries,provinces,or bysome other

geographical b re ak do w n. If t he m ap is t oo large for the folder, it is be tt er t o fold them ap o nc e o r tw ic e t ha n t o ro ll it. A ro lle dmap is difficult to identify, space consumingt o store, and a pain to unroll to loo k at.Two map folders fit n icely s ide by s idein a s tandard map file (42" x 54"). The mapfile comes in five-drawer sections. Map filescan be easily im provised from open-endw oo de n cases, and th e t o p can be use d for

spreadingoutmaps.

wall maps

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SECTION 3 . PLOT REMOTELY SENSED IMAGERYInfrared (IR) imagery, described in TM30-245, pages 2 through 25 , is p roduced byan airborne scanning unit combined with theforward mot ion of the a irc raft. The result is an effect of "pa in t ing" nar row s tr ips on theground. These str ips are added to each otheras the a ircra ft moves forward and the to ta lground coverage is similar to tha t of visual

stripphotography.Side looking airborne radar (SLAR) imageryis produced by a m ethod similar to th em eth od used t o p ro du ce IR im agery. T heradar " looks" out from each side of the airp lane in a narrow beam . T he n t he airp laneflies ahead and the radar takes another looks ideways . These " looks" (or side scans) a re addedtoeachotherontheradardisplaytube.A p ictu re is taken of th em , like taking ap ic tu re of your TV screen . T his p ic tu re ofthe radar isyou r SLARimagery.Soyouhavea photograph of a recording display in bothcases, SLAR and IR , b ut of tw o differentt ypes of energy. In t he case of SLA R, t heenergy is a radio wave and in the case of IR,itisaheatwave.

Since the ground coverage of SLARandIR is similar to that of visual s tr ip photography, you p lo t all imagery about the sameway.Simplyplotthewidthofgroundcoveredby two parallellinesonan overlay overabasemap Use sym bols and an no tatio ns as indicated in FM 3 0-2 45 , pages 5 thro ugh 1 7.F requently th e plo t will " ru n " from onetopogra ph ic sheet on to t he nex t. Y ou w illneed many large-scale maps , o r be tt er , p lo tto a small-scale one such as 1:250,000.

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CHAPTER 4

USE THE DATA FILE

SECTION 1 . ANALYZE SOURCE MAPS MAPPROJECTIONSThe ear th is a g lobe and a map is flat.

INTRODUCTIONTOMAPREADING T here is no w ay to flatten a globe w i thou tstretch in g or tearin g. If y ou s tre tc h, y ouAs a terrain analyst, you will read maps d is to rt th e areas or shapes of areas t o bet o e xtr ac t in fo rm ation for te rra in studies. show n. As long as th e area is sm all, th eYou will alsouse amap asabaseupon which distort ion is not great , as on a cityorcou ntyto add this information to compile your data map B ut w hen th e areas are of c on tin en ta loverlaysorspecialpurposeoverlays. size, th e d isto rtio n m ay be serio us. W hencont inent s are shown, each with its correc tTo best u nd erstan d and use th e m ap area,th eshapeisbadly distorted.information, refer to the legend, which conta ins symbols of te rrain and manmade fea- This distortion isaresultof "projecting"turesshownonthemap. the shape of the globe , a sphere , onto a fla tsurface . The firs t s tep in makinga map pro-Always look at the legend before using je ction is t o dete rm ine geographic c oo rd ithe map .Formoredetailsregardingmapsym- nate s. For a global (worldwide) p ro jectionbols , refer t o FM 21-30 , Military Symbols , you w ould m ark a sphere w here it w ouldMay 1970, and FM 21-31, TopographicSym- slice in two, in t he middle , like an orange.bols,June1971. Thismark isthe equato r.

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T hen im agine t ha t y ou c ut th e sph erei nto a n um b er of o th er h oriz on ta l slices ofequal distances apart, l ike slicing an egg. Callthese marks " la t i tude" lines north and southof the equator . Then divide the equator in to 360 degrees of " longitude" where each divisio n is sliced th ro ug h t he N o rth and S ou thPoles of the sphere. Let' s call the firs t sliceof longitude the prime merid ian and numberall o th ers east or w est of it. T he lines oflong itude and l at it ude form the geographic c oo rd in ate system described in detail inFM21-26,chapter3.

EQUATORPRIMEMERIDIAN

Here is pa rt of the Geograph ic Coord inateSystem.

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T he re are m any w ays to show th is c oo rd inate sys tem on a flat paper. One of the most frequently used methods isaconicproject ion . Imagine that the cartographer (mapmaker) p laces a cone of paper, like a duncecap, on a t ransparen t g lobe . He pu ts a lightbulb in the center of the globeandtracesthegrid shape and c on tin en t outlines on th epaper hat . He then unwrapstheconeand thisis his map of that area. Of course the map isnot actually made in this way, but this comparison shows the theory of the con ic p ro jection.

More complete details of types of conicpro jections are pre sen ted in TM 5-24 1-1,SectionIIandTM30-245,chapter5.

Genera lly the d isadvantage of a con ic projection is that the larger the d is tance between two points on the cone, the larger thedistortion and error will b e.Asacompromisesolu tio n t o th is p ro ble m t he c arto gra ph eruses many differently shaped cones, one for each belt around the earth. This produces a project ion called "polyconic" , in which thelongitude and latitude lines have pronouncedbends.

Geometryofa conic projection.

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The p ro ject ion used fo r a map depends on (1)the part of the worldto bemapped, inc lu din g b ot h size and lo ca tio n, and (2 ) t hepurpo se for which the m ap will be used.Every advantage gained for one purpose (sayconsis tency of scale) must be a t the expenseof som e o th er factor (such as accuracy ofshape).

For navigation, neither shapenorscaleisas impor tan t as the ability to p lo t compasscourses as straight lines. This istheadvantageof the projection known as Mercator , whichhas been used for cen tu ri es in nav igationa lc ha rts . I t is easily recog nized b ecau se t he parallels and meridians are all straight l ines, an d t he p arallels g et progressively fa rth erapart toward the poles. This produces seriousdistortion of areas in thehigherlatitudes,b utit d oe s n o t affect th e m aps usefulness fornav igation. For example , if you were to fly from San Franciscoto Yokohamaandheadeddue west using a Mercato r char t, your compasscoursewouldlooklikethis:

3 0I5OW 120

A "grea t c ir cl e" , which is t he shortestd is ta nc e b etw ee n tw o p oin ts on t he g lo be ,appears longer on a Mercator projection . Soa gnomonic projection wasdesigned inwhichevery great c ircle appears as a s traight l ine .G no mo nic pro jec tio ns are used t o lay o utlongsailingandflyingroutes.Fordescriptionsand usesof other mapprojections, seeTM30245,chapter 5.

* '8 0 * |70W4-4



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Theprojection mostusedby theArmyisa m od ific atio n of t he Mercato r p ro jec tio ncalled Transverse Mercator, designed for areas PLANEOFPROJECTIONbetween 84 north and80 south,wherepractically all the inhabited land of theearthlies.(See sec tion I I, TM 5-241-1 and chap te r 3 ,FM21-26.)

Forareasinhighlatitudes,aPolarStereographicprojection isused.Thesearethe Northand South polar regions.In thiscase aplane POLARCASEistangent to the sphere atthepoleanddetailisprojected onto it.

GEOGRAPHIC COORDINATESLet'sgobacktopage4-2wherewedividethe earth into merid ians and paralle ls. Welabe l the pa rallels in degrees , minutes andseco nds n ort h or sou th of t he E qu ato r andthe meridians indegrees,minutesand secondseast or west of the prime meridian. Now we 3915'20"NORTHcan loca te any point on the earth by longi- LATITUDEtudeandlatitude.(SeeTM5-241-1.)

7630'10 "WEST LONGITUDE

MILITARY GRIDSSoldiers in th e field soon found t ha tgiving o rd ers by lo ng itu de and la titu de t odesignate exact locations and directions wasmost cumbersome. To confuse the s ituation even more , t he leng th of a degree of longitude varies with d is tance from the Equator .So military grids weredesigned. Almosteverygeneral staff designed i ts own, however, andsoon there were dozens of grids and endless co nfus io n. T his all led t o a do ptio n b y th eU.S. A rm y of t he Military G rid ReferenceSystem for identifying locations on mili tarymaps. This system uses the UTM (UniversalTransverse Mercator) grid between 80Sand84N latitudes;for thepolarregions(northof84N and sou th of 80 S we use th e UPS(UniversalPolar Stereographic) grid.

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FM21-33

Using the Military Grid Reference System, you will not identify points by la ti tudeand longitude but ra ther by a series of numbers and letters that designatesquaresofvarious sizes on theearth's surface. Thelargestofth ese squares are 1 00 ,0 00 m eters on eachside.Theyaredesignatedbytwoletterswhichplace the square within a "grid zone" that is 6 degrees wide (in longitude) and 8 degrees high ( in lati tude) . For example, Fort Belvoir is in 100 ,000-mete r square UT, with in grid zone 18S . You can find th is in fo rmation in the lower margin of amap of the Fort Belvoirarea(intheIndianHeadsheet).

314 31 5Scale1:50 000

GRIDZONE DESIGNATION:Gridzone - 18S100.000 M.SQUARE IDENTIFICATION

100,000-metersquareIGNOREtheSMALLERlifuresofinygrid number; these art for f indingthfullcoordinates. Use ONLY theLARGERfiguresof thegrid number;

316 317

TO GIVE A STANDARD REFERENCE ONTHIS SHEET TO NEAREST 100METERS

318 05' 319

Theseare 1,000-metergridsquaresSAMPLE POINT: ALEXANDRIA CHAPEL1. Read letters identi fy ing 106.000 metersquareinwhichthepointlies:

2. LocatefirstVERTICALgridlinetoLEFTofpointand read LARGEfigureslabelingthelineeither inthetoporbottom margin,oronthelineitself:Estimatetenthsfromgridlinetopoint:

3.LocatefirstHORIZONTALgridlineBELOWpointand readLARGEfigureslabelingtheline either inthe left orrightmargin,oronthelineitself:Estimatetenthsfromgridlinetopoint:

SAMPLE REFERENCE:IfreportingbeyondI I inanydirection,prefix GridZone Designation,as:

UT

0 8 - - - - /6 7 -

3UTO8K73 Referencetonearest18SUT0S2C73 100meters

HowtheIndianHead,MD,VAsheetfitsintotheMilitaryG rid Reference System

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W hen y o u are finding a p os itio n on alarge-scale topograph ic map , you are more interested in the 1,000-meter squares, whichare called "grid squares."Theseare identifiedb y a 4-digit n um b er. Y ou get t he first t wodigits by reading the numbers onthe bottomof the grid from left to r ight and the secondtwo by reading up, i.e ., you read "right andup . " T his gives y ou t he n um b er for a gridsquare. 83

82

80READ RIGHTandUP 100t 12 13 14 GRIDSQUARE1181

Nowtofindyourlocationinsidethegridsquare ( to the nearest 100meters) ,you needtwo more d ig it s, one for the horizontal axis and one for the vertical axis . So with in thegrid square,you estimatehowmany tenthsofthe way you are over to the right, and howmany tenths of the way up you are.Supposeyou are 5 /10ths to the r ight and 3/10ths up,th en y ou insert these t o m ake a six-digitnumber,suchas: 82 GRIDSQUARE1181

5/10TOTHE "R IGHT" ->

POSITION115813

81

3/10"UP"

ThisisjustasummaryofhowweusetheMilita ry Grid Refe rence Sys tem. For more in fo rmation abou t how it is de rived and its worldwide app li ca tion , see FM 21-26 , Map Reading.4-7



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WORLD GEOGRAPHIC REFERENCESYSTEM(GEOREF)

This is a w orldw ide position reference 15 belts lettered A to M beginning at th esystem used p rim arily by th e U .S .A ir F orc e. S ou th P ole. T hu s y ou have 2 88 q ua dra ng le sIt uses geographic longitude-latitude in de- each identified by tw o le tters. Each quadgrees and m in ute s w ith a sim plified schem e rangle is subdiv ided in to o ne-d egree sq ua re sof reference. The world is divided in 15 and m arked A to Q. T hus four letters willb an ds of lo ng itu de , le tte re d A t o Z (w ith I id entify a 1 q ua dra ng le , for e x am p leBGMQ.and 0 omi t ted ). La titude is also d ivided in to Furtherdeta ils are in FM21-26 .

TheGEOREFsystemisusedforairnavigation and global reference. It uses degrees and minutes but records them by let ters andnumbers star ting from the 180 meridian andtheSouthPole.A B C P g F G H J K L M . N P Q . R S T U V W X Y Z

Origir

SCALEAND DISTANCEA m ap is draw n to scale. T he scale ispr inted at the bottom andtopof themapl ikethis: 1:50,000. It m eans t ha t 1 foot on th emap equals 50,000feet ontheground. At theb ot to m of th e m ap , y ou 'll see also one ormore bar scales. Topographic maps used bythe Army generally have bar scales in threedifferent units.

Here's how to use the bar scale tom easure distance on th e ground. Take ap iece of p ap er and m ark o n it t he d is ta nc ebetween twopoints onthem ap.

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Then pu t th is paper, with the two marks on it, n ex t to a b ar scale and read on th e b arscale what the distance represents. For moredetails,seeFM21-26,chapter4.

ELEVATIONAND RELIEFHowhighisthehillandwhat'sitsshape?Elevationistheheightaboveareferenceplane,usually mean (average) sea level. Relief is thec onfig ura tio n of t he te rra in . Of th e m an yways to show relief, t he m o st c om m o n w ayis by c on to ur lines. A c on to ur line is anim aginary line on th e ground c on ne ctin gall p oin ts of equal elev atio n. T he spacing andarrangementofcontoursshowthevariousshapes of the h ills and s teepness of s lopes.

Descriptions and i llus trat ions of s lopes andshapes such asvalley,waterbasin,ridge,spur,saddle, depression, cut and fills, andcliff, areshowninFM21-26,chapter6.Alsodescribedand illustra ted are other m ethods ofd ep ic tin g relief suc h a s h a c hu r es , sh ad e drelief, and form l ines .

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DIRECTIONANDLOCATIONHow to find yourlocat ion onamapwasdescribed on apreviouspage.Azimuth isreadin degrees from north . The compass, like a

c ircle, is d iv ided in to 360 degrees . North is 0 or 360 ;eastis90;southis180;andwestis270.\N

To p lo t (o r measure ) the azimuth on a mapy ou will use a p ro tr ac to r. T ec hn iq ue s arecoveredingreatdetailinFM21-26.

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FM21-33

PRINCIPLESOFLAND NAVIGATION t ha t is new or p artly new to y ou , such asGreek or Russian, but you will find that withLand navigation istheab ility of asoldier alitt leconcentrationthisisnotsohardtodo.to find hiswaycross-country,determininghisd ire ctio n w ith a c om pa ss, t he s ta rs , or t h e It pay s t o learn w ha t c om m o n te rra in sun, and by terrain association, dead reckon- features are called in various languages. For ing, and m ap readin g. H ow t o do it is d e- e xa m ple , in Cen tra l A sia a m o un ta in passscribedinFM21-26,chapter5. might be shan-hou in Chinese, hotol in Mongolian, la in Nepaleseand Tibetan, pereval inANALYTICAL PHOTOGRAMMETRIC Russian, or an in Kashmiri . Ar iver would bePOSITIONING ho, gol, khola , chhu, darya, and chu in these

This invo lves the use of geometry and samelanguages.m ath em atic s t o d ete rm in e t he position of The Army has compiled a summary ofpoints on aerial photos involvingscale,paral- the characterist ics of the maps of most counlax, and relief displacement. Techniques are tries of the world, which you willfind usefuldescribedinTM30-245. inany terrain study of a foreign area. ThisisTM5-248,ForeignMaps.USEOFTHEPLANIMETER

A p lanimete r is an ins trument used tomeasure areas of i rregular shapes on maps or SECTIONZ INTERPRET IMAGERYp ho to gra ph s. T he t yp e t ha t y ou w ill use iscalled a "polar planimeter ." This instrumentis an ch ore d a t o ne e nd , a nd y ou tra ce t he AERIAL PHOTOGRAPHYarea's outl ine with the movable point on theother end. Detailed instructions are furnished Aeria l photographs are taken from air-w ith t he in stru me nt b y th e m anu fac turer. p lanes with cameras pointed a t t he g round .T he p ho to gra ph s are fre qu en tly called airFOREIGNMAPS photos. Therearemanytypesof camerasandphotos, such as high obliques, low obliques,N o t all of t he m a ps y ou w ill u se in t er- v ertic al, p an ora m ic , an d s tri p, a nd m an y difrain an aly sis w ill b e p ro du ce d b y t h e U .S . ferent scales. The in terpreta t ion techniquesGovernment. In s tudying foreign areas , you and instruments used range from very simplewill often need to uselocallyproduced maps, t o extrem ely so ph istica te d. T hese are d e-ei ther because they show details that are not scr ibed in TM 30-246,FM 21-26,chapters 8on the maps madeinthe UnitedStatesor be- and9ofFM30-245,andtheManualofPhoto-cause they a re all t ha t will be availab le in graphic Interpretation by th e A mericansomesituations. Society of Photogramm etry.

Y our biggest p rob le m in using th es e You will a lso make use of photo inter -m ap s w ill b e o ne of language. Y ou sh ou ld pretat ion "keys." These show typical exam-have some sort of table of equivalent terms ples of w hat terra in features lo ok lik e onforthelanguageyourmapisprintedin.Some- aerial photos .Theyareessentialwhenyo uaretimesthisisgiveninthe margin onan English- s tudy ing an a rea tha t cannot be checked onlanguage map of a foreign area, or placeswill t he g round. Most pho to int erpret at ion keysbe labeled in both the native language and in (PIK) are classified, for al isting of them seeEnglish. You may have to learn an a lphabet Appendix Aof FM30-10.

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HEIGHTANDDISTANCE DETERMINATIONFROMAERIAL PHOTOGRAPHYAlthough many extremely sophisticatedinst ruments have been developed to measure

distance on aerialphotography,someof themoperated automatically bycom puters,theter

rain analystwill most frequently usebasic andsimple techniques. Some of you rtools will bethe same as thoseusedin photointerpretat ionand dra fting, such as t he 2Xpocke t s te reoscope with parallax bar, tube magnif ie r wi th ameasuringbase,draftingtools,plottingtemplate, andpho tointerpreter's sliderule.

Pocket stereoscope 2X 4Xstereoscope

Carryingcase(ink,pens,maskingtape,etc.)

Drafting set

Parallaxbar

Plottingtemplate

TheTerrain Analyst 'sOffice Equipm ent4-12



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PHOTOINTERPRETER'SSLIDE RULEThis slide rule wasdesignedespecially topermit rapid calculationsof(1)dimensionsofobjects on photos, (2) scale of photos when

al ti tude and focal length are known, (3) alti tude required for a desired scale with a parti cu la r focal leng th , (4 ) g round covered by any scale of photography, (5) percent of forward overlap, (6 ) g round d is tance between adjacent f light l ines, (7) exposure interval tomeet photo overlap required . You will needto be able to do the first two of these operat ions on the slide rule; the others are mainlyfo r flight p lann ing. See sec tion 3-10, page 3-63of FM 30-245for examplesof operation.PHOTOMOSAICS

Y ou w ill on ly n eed t o p re pa re u nc on trol led mosaics, that is ,mosaics that are not adjusted to exact measurements. The photos are simply overlapped by matching images and are stapled or glued together . Details aredescribedinTM5-240,chapter9.DRAFTING PRINCIPLES FOROVERLAYPREPARATION

Overlays are prepared for color separat ion by pen and ink draft ing orscribingtechniquesdescribedinTM5-240,chapter8.PHOTOGRAPHICTECHNIQUESENRECONNAISSANCE

It is often valuable to o btain groun dphotos usinghandheld cameras to gather terra in data when on reconnaissance. Thei r usefor this purpose is expla ined in TM 11 -401,TM11-401-2,FM5-36,andFM30-10.NONPHOTOGRAPHIC IMAGERY

Rad ar and infrared im agery is m os tly supplementa l t o ae rial pho to interp re ta tion.For informat ion concerning i ts use, see TM30-245,TM(C)30-245A,RemoteSensing,bythe Nationa l Academy of Sciences , and Remote Sensing for Environmental Analysis, byJ. Estesand L.Senger.

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Imagery from satellitetransmissions, described on a previous page, is of very smallscale (about 1:1,000,000 and still experimental. Its use in terrain analysisislimited toicepack reconnaissance, snow cover, andshore line measurement. For more in fo rmat io n , see th e tw o b oo ks on re m ot e sensing listedabove.

SECTION 3 . INTERPRET WRITTEN INFORMATION

WHATTOUSEIn chapter 2,wetalked aboutth e varietyof sources that you can d raw on for te rr ain information. Written sources (in contrast to maps and photographs) are especially diversesince they can be any th ing from touri st advertising to scientif ic art icles. The importantthingto remember is that you should be alert to use any source thatcan fill inpiecesof the"jigsaw puzzle" that wecall terrain. Youwillfind travel magazines such as the Na tiona lGeographic or similar periodicals from otherc ou ntrie s especially useful b ecause of t heillustrations andm apsthey contain.

HOWTO EVALUATE ITDrawing on avariety of sourcesdoes notmean you should not be crit ical of them. Onthe contrary,you should continually question

the accuracy of the wr it ten mat te r that you use w h eth er it is b oo ks , m agazine a rtic le s,brochures, or whatever. Ask yourself whatitspurpose was,and whether the author wastrying to sell something orhad apersonal "ax togr ind." Whatdo you knowabout the author?Isheanau thority inhisfield orsomeone whojust v is ited the area briefly in order to get a quick story? Finally, how recent is the inform atio n? If it is 10 or 20 years old, w hatchanges m ig ht have o cc urre d in t he m ean time?



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WHATTODOWITHITThere sire several ways to handle information from written sources:1. If youfind i t tobeunreliableandn otw orth keep ing, you shou ld m ake a no te ofthe source (on a 3x5 card or in a no tebook)with your opinion of i t soyou will notwastetimeonitagain.2. If you find w orthw hile in fo rm ationin i t, you should make note s on the ca rd orin y ou r n ote bo ok . You can eith er ex tractda ta then and there, o r you can wri te downthekindofd ataforfuture reference.3. Instead of an in term ed iate file ofnotes, you can copy the da ta tha t you mightneed d irectly on to a map overlay or photograph. R em em ber t o show in th e m argin,or by a symbol of some kind, where th einformation came from.


1978 US Army Terrain analysis, part 1 36p.pdf

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