Cartographic models - GIS Courses€¦ · Cartographic models Application of spatial operations...
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Cartographic models Application of spatial operations such as buffers, interpolation, reclassification, and overlay to solve problems For example, suitability analyses; see Labs 9 and 10 •Often temporally static; values don’t change during the model period •It may include a temporal component when it compares change through time (comparing vegetation in 1990 to vegetation in 2000)
Transcript of Cartographic models - GIS Courses€¦ · Cartographic models Application of spatial operations...
CartographicmodelsApplicationofspatialoperationssuchasbuffers,interpolation,reclassification,andoverlaytosolveproblemsForexample,suitabilityanalyses;seeLabs9and10
•Oftentemporallystatic;valuesdon’tchangeduringthemodelperiod
•Itmayincludeatemporalcomponentwhenitcompareschangethroughtime(comparingvegetationin1990tovegetationin2000)
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CartographicmodelingCombinegeneraldatasets,functions,andoperationsinasequencetoanswerquestions.
Examples:-wherearethebestplacestositeasolarplant?-whereisthebestwolfhabitat?-wherearethemostvulnerablecitiestooil
increasedoil-railtransport?-whereisthebestplacetobuildanewpark?
Cartographicmodeling
Questionsascriteria:“bestplaceforparks”meanswhat?
1)Nearroads…..whatdistanceisnear…500m?
2)Nearwater,samequestion…200m?
Additionalrestrictions3)Notinwetlands(howtoidentify?),
4)Notonhydricsoils(howtodefine?)
Cartographicmodeling
Stepsfromquestiontosolution
1)Identifycriteria,relativeranking
2)Quantifythresholds,values,asneeded
3)Identify,assessdataneeds,availability,
4)Listspatialoperations,sequence
5)revisitquestion/criteria,orapply
Cartographicmodeling
Cartographicmodels
Oftenrepresentedwithflowcharts;graphicallyrepresentingthespatialdata,operationsandtheirsequence
Combinationsasanadditiveprocess
DiscreteandContinuousRankings
TheBasisforRankings
ExampleWeightings–DistancetoRoads
Example–slopesuitabilityranking
WeightingsAmongLayers:Howdoyoucombinetherankingsfromvariouslayers?Therelativeweightsamongyourinputlayerswillsubstantiallyaffecttherelativesuitabilitiesyoupredict.
DeterminingWeights
•Unscaled• Commonscale• ClientorExpertSurvey(iterative)• Rankorderweights
Weightsmustbejustified
RankOrderDeterminationofWeights
20 operations 15 data layers
20 operations 15 data layers
20 operations 15 data layers
PointstoRemember:•Problemisclearlyspecified,appropriateforGIS?•Spatialandattributeaccuracyrequired?SuchDataavailable,particularlyinclusionsandmmu?•Commoncoordinatesystem/datumsforalllayers•Adequatelayerextent?•Rasterandvectordata,conversionmethods?•Whataretheprimary“branches”ofanalysis?•Howdoyoujointhesebranchesintoananalysistree(diagram)
