gis for applied economics · gis for applied economics juan carlos muñoz-mora univeristat pompeu...

GISforAppliedEconomicsJuanCarlosMuñoz-MoraUniveristatPompeuFabra

Nov2016

juancarlos.munoz@upf.edu

Overview

Learningbydoingapproach(½theory/applications-½practice)

Wewillreplicatepublishedpapers,yetwecanconsideruseyourownresearchaspractice

PracticeOption1:AsingleproblemsetattheendOption2:Smalltaskaftereachsession

WhyshouldwecareaboutGISinEconomics?

ItisnotnewconceptinEconomicthought!

[...]ifeconomicsprofessionhasnotablyneglectedit[geography],thisisnotbecauseeconomistshavebeen

uninterestedinthesubject,butbecausetheyhaveregardeditasintractable.

Source: .

So,what'snew?Fujita,M;Krugman,PandVenables,A.,1999

[1]NewamazingGISdatasetsavailableout

thereprovidesaoriginalsourceofvariation

Remotelysensedinformation.(DonaldsonandStoreygard,2016)

accesstoinformationdifficulttoobtainbyothermeansunusuallyhighspatialresolutionwidegeographiccoverage

Otherexamples: , , ,Michalopoulos&Papaioannou( , ), ,amongothers.

(VernonHenderson,J.;Storeygard,A.andWeil,D2012)

Hendersonetal(2012) Pinkovskiy&Sala-i-Martin(2016) Hodler&Raschky(2014)2013 2014 Alesinaetal(2016)

HistoricalMapsrecoveryold(persistent)

characteristics

Digitizedby .Hefoundanegativerelationshipbetweenthenumberofslavesexportedfromacountryandcurrenteconomicperformance.

Thenuseby ,Michalopoulos&Papaioannou( , , ), ,,etc.

Nunn(2008)

Nunn&Wantchekon(2011) 2013 2014 2015 Alsan(2015) Alesinaetal.(2016)

Geo-Codedindividual-leveldatasets

exploringgeographyandlocationasanimportantdimension

→locationpatternsofindustriesinUKOthersexamplesofgeo-codeddatasets:.

(Duranton,D.andOverman,H2005)

LSMS-ISA(WorldBank)->geo-codedhouseholdlevel6Africancountries

[2]GISmayimproveempiricalstrategystronger

reducingtheomitted-variablebias(I)

gatheringmoreinformationfromneighborhood

↑transport→↑housepricesOtherniceexamplesare:(i) sociallearninginthediffusionGhana;(ii)

directandspillovereffectsoflocalstatecapacityinColombia

Gibbons,S.andMachin,S(2005)

Conley&Udry(2010) Acemoglu,D;Garcia-Jimeno,C.andRobinson(2014)

reducingtheomitted-variablebias(II)

buildinginstruments

CurrentAfricanCountries&SlaveTradesInstrumentSlaveExport→distancesfromeachAfricancountrytothelocationswhereslavesweredemanded

Nunn(2008)

NewidentificationstrategiesSpatialRegressionDiscontinuity

CurrentAfricanCountries&SlaveTradesColonialInstitutions(Mita)→currentoutcomes

Dell(2010)

Exogenousunitofanalysis

MontalvoandReynal-Querol(2016)

[3]Providesanewdimensionstogatheringmicro-leveldata

ImproveyourdatacollectionMostcollectiondatasoftwareallowstogatherGPSlocation(e.g.ODKSurvey,

SurveyCTO,CAPI)

CrackingGeo-SpatialDatasets"Geo-spatial"data

Theterms"geo-spatial"referstoinformationthatislocatedontheearth'ssurfaceusingcoordinates.

"Geo-spatial"dataType(e.g.line,area)

Attributes(e.g.temperature,...)HowcanIrepresentthosepoints,lines,andareasonthe

surfaceoftheearth?

Location(e.g.coordinates)

GeodeticLocation

Latitude→north-southdirection,relativetotheequatorLongitude→east-westdirection,relativetoanarbitrarypoint(typicallythelocationoftheRoyalObservatoryinGreenwich-

England)

...yetearthisnotaperfectsphere,itismorelikeanoblatespheroid.

ThemathematicianCarlGausseprovedthatitismathematicallyimpossibletoproject shape(e.g.sphere),ontoaflatplanewithoutintroducingsomesortofdistortion.

R3

Whatshouldwedo?cylindricalconicalazimuthal

...weneedtochooseadistortionthatfitsyourneeds

CylindricalProjections

ItincludetheMercatorProjection,theEqual-AreaCylindricalProjection,andtheUniversalTransverseMercatorProjection.

ConicalProjections

ItincludestheAlbersEqual-Area,theLambertConformalConicProjection,andtheEquidistantProjection.

AzimuthalProjections

ItincludestheGnomonicProjection,theLambertEqual-AreaAzimuthalProjection,andtheOrthographicProjection.

CoordinateSystem(pointdirectlyontheearth'ssurface)

NotProjections

(pointonatwo-dimensionalmapthatrepresentsthesurfaceoftheearth)

UseProjections

UnprojectedCoordinateSystem

→ ( , )x0 y0

ProjectedCoordinateSystem

→ ( , )x0̂ y0̂

..stillsomethingmissingyet,wesaidthattheearthisnotaperfectsphere

Datumisamathematicalmodeloftheearthusedtodescribelocationsontheearth'ssurface.Adatumconsistsofasetofreferencepoints,oftencombinedwithamodeloftheshapeof

theearth.

Mostcommondatum:NAD27,NAD83andWGS84

"Geo-spatial"dataLocation(e.g.coordinates)

Attributes(e.g.temperature,...)HowcanIrepresentthosepoints,lines,andareasonthe

surfaceoftheearth?

Type(e.g.line,area)

VectorData

Point(lat, lon)Linestring Polygons Polygons

Rasterdata(imagesasdata)Geo-locatedmapset

Pixelcharacteristicsasmainattribute

Classified(Remotesensitivedata)

RasterData

RasterData

Polygons

Polygons

Linestring

Point

"Geo-spatial"dataGISdataformat

Gettinggeo-spatialdatasetintoafile(s)

ManyformatsavailableRasterData

DEM,geo-tiff,bandbasedfilesVectorData

Shapelife,Simplefeatures,TIGER/Line,...micro-format(WKT,GeoJSON,...)

Shapefile.shpitcontainsthegeometry(type).shx fixedsize.dbf attributes(database)

Otherfilessuchas:.prj(projections)...Samefilename,yetdifferentextensions

developedbyESRI

GIStools

C,C++andPythonbasedsolutions(objected-oriented

syntaxis)

Source:Lawhead,2013

PointArcGIS

CommercialSoftware

Pre-definedpythonpackage-ArcPy(+Model

Builder)

Memorydemanding;Windowsonly

QGISOpensourcesoftware;easytocreatemapimages;

Pre-definedpythonpackage-PyQGIScompatiblewithanyOS(evenandroid)

Moredifferences

StandalonesolutionsCompletecontroloftheunderlyingalgorithms,data,andexecution(no

blackbox)

Integrationwitotherspythonpackages

Solutionno-softwaredepending(replicationandcollaborations)

GISanalysisbeyondthebottoms

Integrationwithnewhigh-performanceenvironment(i.e.cluster,cloud)

Readyforstarting?-sampledatasets

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