Mapping

Chapter TopicsMaking Accurate Map ProjectionsLatitudeLongitudeGreat CirclesMap ScaleContoursSlopeRemote SensingGIS

Making Accurate Map Projections

Distortion

Round surface on a flat paper

Mercator,gnomic,conic most common

LatitudeThere is an imaginary line of latitude halfway between the North Pole and the South Pole called the equator. There are other lines of latitude that are north and south of the equator. They are parallel lines which are equal in distance apart at all points. They run east-west around the globe. Parallels measure distance north or south of the equator in degrees.

LongitudeThere are also imaginary lines of longitude that help us measure distance east and west. Each line of longitude, or meridian, runs from the North Pole to the South Pole. Mapmakers needed a place to begin, so they created the Prime Meridian as this starting point. Meridians are the farthest apart at the equator, and they are closer together at the poles.

Latitude and Longitude

Measured in degrees.

Latitude 0-90 North or South

Longitude 0-180 East and West

Broken down further into minutes and seconds

Example: 12º 32’ 8” N

Great CirclesShortest distance on a round surface in an arc.

Map ScaleGraphic

Verbal

Representative fraction

Example 1:5000

One inch on the map is equal to 5000 inches in the real world.

Contour LinesConnects areas of similar elevation.

Contour interval

Index Contours

Make 3D models from 2D lines.

SlopeRise in elevation over the run the distance.

Rise / Run

Geographic Information SystemsGIS

Introduction Computer tool: geographic map + tabular data

Integrate: Database, Mapping, Analysis

Create maps which convey information

Countries w/ Population>100 million

What is GISPowerful computer mapping/analysis system

Easily make/update maps

Analyze locations & Present info as maps to:

Integrate maps & info from variety of sources

Make decisions about resources, planning, site selection, demographics

How GIS worksLinks map features to tables of attributes

Access the attributes for any map feature

Locate any feature from its attributes

Manage sets of features & attributes as themes

Basic Features

Create maps

Make queries, what if scenarios

Summarize and analyze data

Integrate information

Remote Sensing

HistoryCivil War: balloon photography

WWI & II: military air reconnaissance

1940: aerial photos for peacetime use (surveying, mapping , soil survey)

1960: digital computer, improved sensors, quantitative pattern recognition software

Improved computers, increased spectral bands & sensor capability, satellite speed, wide range of altitudes/resolutions lead to large quantity of info

Defined

Use of airborne sensors (mainly satellite)

which measure electromagnetic radiation of objects

to monitor, analyze & extract info about earth features and the environment

ImportanceLarge changes are happening

Observe location & extent of human activity and land cover

Monitor rates of change

Make global evaluations

Link to GIS

Why use RS (vs ground survey)

Large regional view

Complete area (spatial) coverage

Temporal change: snapshots over time

Cost effective

OtherCan provide 3d view

Detect characteristics not visible to eye

Uses: land, air, water, space Vegetation: forests, crops , range lands

Soils/Geology: terrain, minerals, faults

Water resources, Marine environment

Environment: ozone, pollution, habitat

Natural disaster: flood, fire, volcano

People: urbanization, population growth

Regional planning, Weather, Global Climate

Cartography mapping, Surveying

Military

Remote Sensing Examples

Cape Canaveral Landsat 7

Oakland Landsat 7

Change: Aral Sea

Change: same area, #3 is change

Change: urban growth D.C.Dark=no change, bright=development since 1973

Landsat TM

Sediment Model

DEM: digital elevation model

3D: stereo pairs

Flood extent impossible by ground survey, green veg

Landsat TM

Floods: Missouri river

Junction w/ Grand riverJunction w/ Grand river

2=B 4=G 5=R Bare soil, plowed land are red, vegetation (hi near infrared-4) is green, water is dark blue.

19931992

Landsat TM

El Nino sea temptop: normalmiddle: el ninobottom: change

Environment: Ozone

Global: snow (microwave)

Global: Vegetation avhrr, coarse, desertification

Deforest: Amazon change, near road

Forest change: U.S.

2=B 4=G 5=R wide range, conifers are dark green, soil or cultivated land is reddish, snow is light blue. Land use policy led to less clearcuts.

19951984

Landsat tm

Olympic natl forest

RS+GIS, Quantify Habitat loss

Hazards: gulf war oil fire Landsat TM

Crater Lower Amazon in Bolivia

1988 scene, not visited until 1998 cause so inaccessible

1988 scene, not visited until 1998 cause so inaccessible

Landsat 1988, inaccessible so no visit until 1999

Volcanoes: Mt St Helens

False vs True: Mt St Helens

1=B 2=G 3=R true2=B 4=G 5=R wide range

Landsat tm May 1992

Scale problem

whaleswhales

QuickTime™ and aCinepak decompressor

are needed to see this picture.