Lab Exercise 4

Government 1008: Introduction to Geographic Information Systems LAB EXERCISE 4: “Got Database? Will Query” Objectives:
 Creatinggeodatabases
 Joiningattributetables
 Attributeandlocationbasedqueries
 Spatialjoins
 Creatingspatialandattributedata
 EstimatedTime:4‐5hours
1.0 Problem: Using database techniques to query and reason with your data Inthislabexerciseyouwillinvestigatetherelationshipsbetweenpopulationdensity,housing
valueandhazardousmaterialsandoilspills(orcrashesorTRIsites).Youwilllearntocombine
multipledatatablesandlayersfromvarioussourcesinmakingqueriesandgeneratingstatistics.
Recallwhatyoufoundinpreviouslabexercisesaboutspills,EnvironmentalJusticeblockgroups,
etc.in(Cambridgeor)otherpartsofMassachusettsandusethatknowledgeingeneratingyour
spatialquestions.
Data used in this part of the lab exercise Datainthemassgisfolderinlab4.gdb 1.0 Geodatabases Tomanageyourownspatialdatabase,youcancreateageodatabase1.Ageodatabaseisa
collectionofgeographicdatasetsofvariousformats.InArcGISageodatabaseisacollectionof
geographicdatasetsofvarioustypesheldinacommonfilesystemfolder,aMicrosoftAccess
database,oramultiuserrelationaldatabase(suchasOracle,MicrosoftSQLServer,orIBMDB2).
Thegeodatabasecancontainthreeprimarydatasettypes:
 Featureclasses
 Rasterdatasets
 Tables
Afilegeodatabase2(*.gdb)offersallthefunctionalityofageodatabase,butitisstoredinafile
structure,whereas,withapersonalgeodatabase(*.mdb)yourdatawillbestoredinaMicrosoft
Accessreadabledatabase(whichyoucanaccessfromoutsideofArcGISinMicrosoftAccessfor
non‐spatialqueries).
1.1 Adding Fields to Tables
Inordertoaddafieldtoatable,threeconditionsmustbemet:
 Youmusthave“write”accesstothedata(soitshouldbeinyourU:driveordesktop)
 YoushouldnotbecurrentlyeditingthedatainArcMaporArcCatalog
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http://www.esri.com/software/arcgis/geodatabase, http://resources.arcgis.com/en/help/main/10.2/index.html (search for
geodatabase)
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Refer to Appendix A to see how lab4.gdb was created
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 Nootherusersorapplicationsshouldbeaccessingthedata.
Ifanyoftheseconditionsarenotmet,the“AddField”optionwillbegrayedoutoritwillnotwork.
Tobeabletoeditaspatialdatafile,therefore,youmustcopyittothedesktoporafolderwhere
youhavepermissiontosavedata.
1. Openanewmapdocument 2. Copylab4.gdbfromthemassgisfolderusingArcCatalogtoyourdesktopifyouareona
labmachine.RemembertocopythefolderbacktoyourU:drivewhenyouaredonewith
thissession. 3. Add
thedata(ordragitfromArcCatalog)for
townsCENSUS2010TOWNS_POLYfromyour
lab4.gdb(nottheoneintheT:drive)inArcMap
4. Opentheattributetableforthe
CENSUS2010TOWNS_POLY(right‐clickinTOCand
thenselectOpenAttributeTable).
5. Inthetable,clickontheTable
Options
iconatthetopright
cornerofthetablewindow.Select
“AddFields”.
6. IntheAddfielddialog,enter
“DENSITY90”intotheNamespace,
“Double”intotheTypespace,settheAliasandDefaultifyouwantto.Click“OK.”Youcan
seethatthenewfieldappearsinthelastcolumn(ontheextremeright)ofthetable.
7. Alsoaddfieldscalled“DENSITY00,”“DENSITY10,”“DENSITYCH90”and“DENSITYCH00”
FIELD TYPES
Text: textual data, letters and/or numbers
Short Integer: integer numbers values between +/-32,767
Long Integer: integer numbers values between +/-2.16 billion
Float: real numbers (positive numbers) to a decimal precision of 7 places (7 significant digits)
(this field type is also referred to as Single)
Double: real numbers (positive numbers) to a decimal precision of 15 places (15 significant digits)
Date: stores dates (and or times); in geodatabases, this field can store the date and the time
BLOB: stores references to Binary Large OBjects like video, audio, word files, or other binary data
PRECISION: For numeric data, precision is the total number of digits allowed (Left and Right of decimal point)
SCALE: Number of allowable digits to the Right of the decimal point and only for Float and Double field types
Youshouldhavenewfields,“DENSITY00,”“DENSITY90,”“DENSITY10”“DENSITYCH90_00”and
“DENSITYCH00_10”.
Note:ToseevariablecharacteristicsfortheothervariablesintheTownsattributetable,right
clickonlayerintheTOC.Thenselect“Properties”andclickthe“Fields”tab.
1.2 Calculating new field values Nowfillthenewfieldswithdata:
8. InArcMap,gotomainmenuCustomizeandthenToolbars
andcheckEditor.
9. Ontheeditortoolbar,selectthe
“Editor”pulldownmenuandclickon
“StartEditing.”
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10. Duringtheeditingofatableitiscommontoselecta
singleoranumberofrecordsbymistake.They
instantlybecomehighlighted.Toclearthisselection,
clickonthe iconinthetoolstoolbarortable
toolbar.
11. Leftclickonthe“DENSITY90”field(column)heading
inthetabletohighlightit.
12. Thenright‐clickoncolumnheading.Scrolldownthe
menuthatappearsandselect“Field
Calculator”togetanewwindow.
13. IntheFieldCalculatorwindow
entertheformulaforcalculating
density:doubleclick[POP1990]on
the“Fields,”clickortype“/”andthendoubleclick[SQ_MILES]onthe“Fields.”
Notethatyoucantypebutyouneedtobecarefultotypeexactlythenamesofthefields
includingbrackets.
14. ClickonOK.Thevaluesfor“DENSITY90”(inpopulation
persquaremiles)willnowappearonthetable.
15. RepeatthetwopreviousstepsforDENSITY00,
DENSITY10byusingtheappropriatepopulationfields.
16. CalculateDENSITYCH90_00(whichisthedifference
betweenDENSITY00andDENSITY90)and
DENSITYCH00_10(difference
between2010and2000).
17. Onceyouhavecreatedthenew
variablessaveyourworkby
clickingonEditorandthen“Save
Edits.”
18. Youcanalsoperformstatisticaloperationsonthefield.
Highlightforexamplethecolumn“DENSITY10”inthetable,
rightclickonitandselectStatistics.Thisbringsupthestatistics
windowthatprovidesstatisticslikemeanandstandard
deviationforthefield.
1.3 Attribute Queries Wecannowquerythenewfieldsthathavebeencreated.Forexampleyoumightwanttoselectall
townsthathave“DENSITYCH90_00”lessthan0orinotherwordsalltownswheredensity
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decreasedbetween1990and2000.Youcanperformattributequeriesthroughthegeographic
datavieworthroughtheattributetable.Asthetableandthemapwindowaredynamicallylinked,
yourselectionresultsshouldbevisibleinbothplaces.
19. Toaccesstheattributequerydialog,clickonthe SelectbyAttributesiconatthetopof
theTableorgotothemainmenuSelection,andclick
“SelectbyAttributes.”
20. A“SelectbyAttributes”windowwillappear–thisisarelationalquerybyexample(RQBE)
whereyoucanconstructaquerywithoutneedingtoknowtheunderlyingStructuredQuery
Language(SQL).NotethatsomeSQLisalsovisibleasin“SELECT*FROM
CENSUS2010TOWNS_POLY”
21. Underfields,scrolldownto“DENSITYCH”anddoubleclickonit.Thenclickon“<”andthen
enter0.ClickApplyandthenclosetheSelectbyAttributeswindow.
22. Thetownswithadropindensityarehighlightedinboththemapaswellasthetable.
Note:Afterthequery,clickon “ClearSelection”iconifyouwanttogetridoftheselection
andmakeanewselectionquery.
23. Clickonanyfieldinthetabletohighlightitandthenclickontherightmousebutton.From
theaccompanyingmenu,youcanselectSortAscendingorSortDescending.
Beforeyouexityoumustsaveyouredits.
24. Todothis,click“Stopediting”ontheEditortoolbar.Whenyouclick
stopediting,youwillbeaskedifyouwanttosaveedits(ifyouhavenot
alreadysavedthem).Click“yes”andyoureditswillbesaved. Remember to save your lab4.mxd document. 4
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Question 1 (20 points) Answer these questions before you move on to the next section Question1a(10points):
Whichtownshadthegreatestdropinpopulationdensitybetween2000and2010(lookatthetop
10)?Whatwouldyoupredictabouthousingvaluesintownswheredensityfell?
Question1b(10points):
Whichwerethedensesttownsin2000(lookatthetop10)?Diddensityriseinthosetowns
between1990and2000(anddidthetrendholdin2010)?Whatdoyoupredictaboutcrime
trendsinthecommunitieswithasteepfall(orsteeprise)indensity?
1.5 Joining tables IfyouopentheattributefileassociatedwiththeTownslayerCENSUS2010TOWNS_POLYyouwill
noticethatitdoesnothaveanycrimerelatedvariables.However,wehaveaccesstocrimedataby
townsinMassachusettsfromtheFBIUCRdatabase(ucr_90_s_vanducr_00_s_v)andthe
documentationtellsusthatthecrimetablesandtownshaveacommonkey:TOWNS_ID.
TheTownsattributetablesharesafieldcalled“TOWN_ID”incommonwiththecrimetablesfor
1990and2000.
25. Add(drag)inthecrimetablesinlab4.gdbtoyour
TOCucr_00_s_v(2000crime)anducr_90_s_v
(1990crime)
26. Right‐clickintheTOCagainstthetable
ucr_90_s_vandthenselect“JoinsandRelates”andthen“Join…”togetanewwindow
called“JoinData.”Completethedetailsofthejoin(withucr_00_s_v)asshowninthescreen
shotthatfollows.“Whatdoyouwanttojointothislayer?”shouldbe“Joinattributes
fromatable.”ThekeyisTOWN_ID.Checkagainst“Keeponlymatchingrecords”foran
innerjoin.Click“OK.”
27. Then,rightclickontheCENSUS2010TOWNS_POLYlayerintheTOC(forwhichyouadded
newfieldsintheearliersection).Select“JoinsandRelates”andthen“Join”.Inthewindow
checkagainst“Keepallrecords”foranouterjoin.Seescreenshotsbelowforotherdetails.
NowtheattributesfromboththecrimetableswillbevisibleintheTownsattributetable
whenyouscrolltotheright.
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28. QuerythistableusingSelectbyAttributes(main
menuSelectionandthenSelectbyAttribute).For
example,thescreenshotshowsaqueryforall
locationswheremurderratesin1990werehigher
thanmurderratesin2000.
Note:JoinsarestoredintheArcMapdocumentitselfbut
arenotpermanentunlessyousavethisdataasanew
shapefileorfeatureinyourgeodatabase.(Rightclickon
thelayerandthenData,ExportData…)
29. Addthecensus2000blockgroups_polylayerin
theLab4.gdbtoyourmapdocumentandjointhe
housing_valuetabletoit.Rememberthatyou
needacommonkeyvariable.Noticethattheblock
groupsaremuchmorefinegrainedunitsthantowns.
Notethatthislayershowsblockgroupsbasedon
datafromCensus2000.
Note:census2000blockgroups_polyandhousing_value.dbf,income_by_household.dbf
shareacommonkeycalledLOGRECNO;
30. AfterthejoinyoushouldhaveacolumntitledVL_MED_OWNintheattributetablewhich
wasthemedianvalueofowneroccupiedhousinginthatblockgroupin2000.Youcanalso
getmedianincomebyjoiningtheincome_by_household.dbftable(lookfortheattribute
orcolumnINC_MED_HS).
31. TogetCensus2010housingvalue(T101_001Medianvalueforowneroccupiedhousing)
orincome(T057_001Medianhouseholdincomein2010InflationAdjustedDollars)for
2010joinCENSUS2010BLOCKGROUPS_POLYlayerandACS0610SocialExplorerData
tablewhichshareacommonkeyGEOID10.
Optionally,youcanalsojoinCENSUS2010BLOCKGROUPS_POLYlayerwhichmapsblock
groupsin2010andthetableCEN2010_BG_SF1_POP_RACEthepopulationtablefromthe
SummaryFile1ofthe2010CensuswhichshareakeycalledLOGRECNOinthetable
CEN2010_BG_SF1_POP_RACEandLOGSF1inthelayertablefor
CENSUS2010BLOCKGROUPS_POLY.Thisgetsyoumoreonpopulationdemographics.
Note1:The“key”columnhastobeofthesametype–bothhavetobetextornumbersevenifthe
valuesarethesame.IhadtoaddanewcolumncalledGEOID10oftypetextintheACStableand
calculatethevaluestobethesameasGeo_FIPS(whichwasanumber).
Thesewereall“one‐to‐one”joins.Todo“one‐to‐many”or“many‐to‐many”joinsyouneedtouse
asimilartoolcalledRelateoraggregatethedatatoperformaone‐to‐onejoin.
Note2:ACS0610SocialExplorerDatatableinthemassgisfolderisdocumentedin
ACS06_10_blockgroupdata_socialexplorer_documentation(atextfile).Notethatallthe
variableshaveanSEprefixtoindicatethattheyarefromSocialExplorer
Remembertosaveyourlab4.mxddocument.
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Question 2 (40 points) Question2a(20points):
CreateamapforonecrimerelatedvariablefromthecrimedatabyTownsinMA.(Thisdoesnot
havetobealayoutthatincludesnortharrow,scaleetc.Attachascreenshotofthemapand
legend).Then,brieflydescribeaqueryyouusedtoassesschangeincrimeandwhatitsuggests
aboutcrimechangesbetween1990and2000.Usescreenshotstohelpyoudescribethechange.
ExplainhowthisconfirmedyourhypothesesaboutcrimeanddensitychangeinQuestion1b.
Question2c(20points)
CreateamapshowinghousingvaluesinMassachusettsin2000versus2010(createtwo
differentmaplayoutsortwodataframeswithinonelayout).Notethatinthislabexerciseyouare
notexpectedtocombinethe2000and2010data(theblockgroupboundarieswillnotmatch
acrossCensuses).Thelegendclassesshouldbecomparable–eitherthesameclassvaluesoruse
quantileclassificationsforboth.
Usethismaptodescribeinafewparagraphswhetheritconfirmsyourhypothesesaboutthe
relationshipsbetweenhousingvalueanddensitychange(inQuestion1a).(Thisdoesnothaveto
beaformallayoutthatincludesnortharrow,scaleetc.Attachascreenshotofthemapandlegend).
1.6 Spatial Queries 32. AddthefinalversionofspillsorcrashesorTRIdataset
thatyoucreatedinthepreviouslabexercisetoyour
ArcMapdocument.(OrusefromtheMassgisfolder:
cambridge_crash_2010_corr.shpor
cambridge_crash_2005_corr.shpor
EPA_TRI_AllReleases_MA2010_pr.shpor
MassDEP_AULspills_pr.shp).
Notethatalltheselayershavebeenprojectedtomatch
theotherMassgislayers.
33. Gotothemainmenu“Selection”andthen“Selectby
Location.”Inthe“SelectbyLocation”windowtryout
spatialqueriesthatcouldassesspossiblespatial
relationshipsbetweenrelevantlayersandcrash(orspill)
locations.
34. Addotherlayersfromthemassgisfolderthatcouldhelp
youexplainanypatterns:forexampleEnvironmental_Justice_2010,MajorRoads
(EOT_Major_Roads),etc.
ThescreenontherightshowshowtosetupaquerytofindalltheCambridgecrashesin2010that
arewithin50mofamajorroad.
35. Youcan
switchtheselectioninthetabletoconductstatisticsfordifferentsubsets.For
exampleCalculatestatisticsformeanof2010medianhouseholdincome(!)inblockgroups
within½milefromspillsversusthoseblockgroupswhichareover½milefromit.
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NotethatACS0610SocialExplorerDatatableisdocumentedin
ACS06_10_blockgroupdata_socialexplorer_documentation(atextfile).
Statisticsonmedianhouseholdincomein2010inblockgroupswithin0.25milesofspillsversusmedianhousehold
incomein2010inblockgroupsmorethan0.25milesfromspills
1.7 Spatial Joins in ArcGIS Tofindoutthenumberofhazardousspillsorcrashesineachofthe
censusblockgroupsyouwouldcreateaspatialjoinbetweenthe
twolayers:spills/crashesandcensusblockgroups.Recall(fromLab
Ex2)thatyoucanonlydotheseoverlaysiftheybothare
georeferencedtothesamecoordinatesystem,projection,datum,
ellipsoid,etc.orifyoursoftwarewillallowprojectiononthefly.
36. Right‐clickagainst2010censusblockgroupslayerinthe
TOC,thenselect“JoinsandRelates”andthen“Joins”.Change
“Whatdoyouwanttojointothislayer?”tobe“Joindata
fromanotherlayerbasedonspatiallocation.”Saveyour
outputtothelab4folder. Ifyourdatahadvaluesthatcouldbeadded(forexampleforTRI
sitesthereleasesforallsiteswithinablockgroupcanbeadded;
foraccidentsthenumberofnon‐fatalitiesorinjurieswithina
blockgroupcanalsobeaggregated)thencheckagainstSum.
37. Whenyouopentheattributefileforthenewlayer(thatis
automaticallyaddedtoyourArcMapdisplay)youwillfindthat
ithasanewvariable“Count_”thatshowsthenumberofspills
(orcrashesorTRIsites)ineachcensusblockgroup.Wheredo
youfindmanyspills/crashes/TRIsites?(Doanattribute
querytofindsuchblockgroups).
1.8 Creating new attribute tables 38. First,addtheSpatialAnalystextension.Inthemainmenuclick
CustomizeandthenExtensionsandthenmakesureSpatial
Analystischecked. 39. Addoneofthefollowingrastersfrommassgisdependingonthe
typeofanalysisyouwouldliketoreasonabout:medianincome
in1999and2010:income99,income10;populationdensityin
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2000and2010calculatedusingblockleveldata:density00anddensity10orlowincome
childdensityin2000(notavailablein2010)calculatedusingblockgroupdata:
lichildden00.Allthedensityunitsareinpersons/sqkm.
Ifyouaddedincomeyouareaskingaboutthedifferencesinincomebetweenvarious
censusblockgroupswithdifferentnumbersofspills/crashes/releases.Thereforeyour
spatialquestionwouldbe“Aretheredifferencesinincomebetweenblockgroupswhich
havenospills(orcrashesorreleasesorTRIsites)versusthosewithspills(orcrashesor
TRIsites)?”
1.8.1 Creating a raster data set from a vector data set (Optional – future reference) 40. ClickontheConversionToolsinArcToolboxandthenToRasterandthen“Featureto
Raster”togetanewwindow.
41. Tocreateanewrasterthatshowspopulationdensityandmedianincomein2010in
500x500mcellsthatwereconvertedfromtheblockleveldata(forpopulation)andblock
groupleveldata(formedianincome)seethescreenshotsthatfollow.
1.8.2 Combining rasters and vectors: Counting points in a polygon 42. ClickontheSpatialAnalysttoolsinArcToolbox,thenselectZonalfollowedbyZonal
statisticsasTabletogetanewwindowasshown.
43. LetspillsorcrashesorTRIsitesbeyourzonedatasetandthe
fieldyouareinterestedisthenumberofspillsorcrashesorsites
(Count_).Inotherwords,youwanttofindtheaverageincome
(thisisanaverageofmedianincome)foreach
site/spill/crashcategory(thenumberofspillsor
crashesorsitesvaryingfrom0tothemaximum).
ClickOKtogetanewtable. 9
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44. YoucanopenthistableinExceland
makeagraph.OrclickontheTable
options
iconandtheninthedrop
downmenuselectCreateGraphtogeta
newwindowwhereyouwantaVertical
bargraphwiththeXfieldisCOUNT_,X
labelfieldisCOUNT_(notCOUNTwhich
countsthenumberofpixelsinthe
category)andtheValuefieldisthe
(housingvalue)mean.
Thegraphappearstoindicateafallingtrend
inmeanofmedianincomeasthenumbersof
spillsinthecensusblockgroupincreasesandthenasteeprisewheretherewere15spills.
(Perhapsoutliers?PerhapshighincomebutcentrallocationsinBoston?).Savethefinalgraphthat
youcreate.
Question 3 (20 points) Writeabriefdescriptionoftheresultsofyourspatialquery(ies).Youcouldtesttheoriesand
reasonaboutafewofthesetheoriesabouttherelationshipbetweenpopulation,income,housing
values,andspills(and/orcrashes)inacensusblockgroup.
Includethescreenshotofatleastonespatialquery(Section1.6)andtwographs(usingthe
StatisticstoolasshowninSection1.6).
Discusstheimplicationsofwhatyoufind.Youcanzoomintoonelocation(likethecityof
Springfield,BostonorCambridge)orlookatoveralltrendswithinthestateoraregionwithinthe
state.RefertoyourmapinQuestion4forthisdescription.
Iwillgradethisbasedonyourcoherenceinstatingyourhypothesesaboutrelationshipsbetween
spills/crashesandothervariablesdescribingthecensusblockgroupsandtheappropriatenessof
thevisualmaterialyouattachtoanswerthequestionsyousetouttonotonthequantityof
visualsormaterialthatyouattach.
Question 4 (20 points) CreateamaplayoutwiththegraphyoucreatedinSection1.8.2,andamapofanyvariablethatis
relevanttoyourdiscussioninQuestion3.(Includelegend,title,northarrow,source,scaleinthis
map).
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APPENDIX A: Creating a File Geodatabase 1. StartupArcMapandthenArcCatalog(within
ArcMap).
2. SelectfromthemainmenuinArcCatalog:File,then
New,thenFileGeodatabase(notPersonal
Geodatabase)orrightclickintheTOCtoselectNewandthenFileGeodatabase.Rename
thisnewgeodatabasetobelab4.
Importspatialdatafilesfromthemassgisfoldertothisgeodatabaseasfollows:
3. Right‐clickagainstthegeodatabaselab4.gdbin
yourArcCatalogTOCtogetamenuasshowninthe
screenontherightwhereyoushouldfirstselect
ImportandFeatureClass(multiple).
4. Youwillgetanewwindow.Importtheshapefiles:
census2000blockgroups_poly(ashapefile
showingcensusblockgroupsinMassachusettsin
2000)andCENSUS2010TOWNS_POLYinmassgisinthegeodatabase
CENSUS2010TOWNS.gdbaswellasCENSUS2010BLOCKGROUPS_POLYinthe
geodatabaseCENSUS2010_BLK_BG_TRCT.gdbwhichhasfeaturedatafor2010block
groups,tractsandblocks.
5. Next,right‐clickagainstthegeodatabase
lab4.gdbinyourfoldertogetamenuwhere
youshouldselectImportandthenTable
(Multiple)togetanewwindow.Importthe
tables
ACS06_10_blockgroupdata_socialexplorer.xl
s(includespopulation,incomeandmedian
housingvaluesforblockgroupsfromAmerican
CommunitySurveyACSEstimates2006‐2010
downloadedfromSocialExplorer),
CEN2010_BG_SF1_POP_RACE.dbf(population
datafor2010fromsummaryfilesCensus
2010),housing_value.dbf(medianhousing
valuesfromCensus2000)fromthemassgis
folder,ucr_90_s_v.dbfanducr_00_s_v.dbf
fromthefolderspoliver_sf_crime_townsin
massgiswithnumbersandratesofvarious
crimesbytownsinMassachusettsfor1990and
2000.
NoteherethatIamcopyingfromthedesktop
whereIhaveacopyofmassgisinsteadoftheT:
drive.
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6. YoucanrenamethetablesandlayerswithinthegeodatabaseinArcCatalogtohelpyou
keeptrackofwhattheycontain
DataforCensus2000forMassachusettsisdocumentedat:
http://www.mass.gov/anf/research‐and‐tech/it‐serv‐and‐support/application‐serv/office‐of‐
geographic‐information‐massgis/datalayers/census2000.html
DataforCensus2010isdocumentedat:
http://www.mass.gov/anf/research‐and‐tech/it‐serv‐and‐support/application‐serv/office‐of‐
geographic‐information‐massgis/datalayers/census2010.html
Massgisalsonotesthat
The2006‐2010American Community Survey(ACS)5‐yearestimatesdataarenowavailable
fromtheCensusBureau,buthavenotbeenprocessedbyMassGIS.Tojointhesetablestothe
geographiclayers(Blocks,BlockGroupsandTracts)providedbyMassGIS,usethe
LOGACS0610fieldinthegeographyandtheLOGRECNOfieldinthe2006‐2010ACStables.
However,IsuggestthatyouuseSocialExplorerorNationalHistoricGIStodownloadthese
dataasexplainedinthenextAppendix.
Alsonotethatifyoudownload2005‐2009ACSdemographicdataitwillNOTlinktothe2010
geography.
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APPENDIX B: Census Data in Social Explorer 1. IntheHollis(HarvardLibrary)website
searchforSocialExplorerandconnectto
itthroughtheweblink.
2. Inthesocialexplorerwebsitelookforthe
MapsandTablesandthenTableslink.
Thisshouldgiveyouaccesstotablesfrom
ACS(AmericanCommunitySurveys),
DecennialCensusdatafrom1790,etc.I
downloadeddatafromACS2006‐2010by
clickingontheBeginReportlink.
3. ForthislabexerciseIselectedBlockgroup(geographic
type),intheStateofMassachusetts,addAlltheblock
groupsinMassachusettsandthenclickedonProceedto
Tables.
4. Inthenextstepselectoneormorevariables(Iselected
income,population,medianincome,povertystatusand
housingvalue).ClickonShowResultwhenyouhave
selectedallthevariablesyouneed.
5. ClickonDataDownload
inthe
nextpage.
6. Tobeabletojoinittoashapefilelateryoushould
downloadbygeographysoclickonBlockgroup
data(CSV).Alsodownloadthedatadictionary
(textfile)fordocumentationofvariables. NotethatmoreCensusdataisalsoavailableat
NHGIShttps://data2.nhgis.org/main
AnotherwaytoaccessUSACensusdataisthroughthefactfinderat
http://factfinder2.census.gov/faces/nav/jsf/pages/index.xhtml
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