exercise 4 - creating and editing spatial data

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  • CreatingandEditingSpatialData

    SpatialDataOneoftheveryimportantthingsthatanArcMapuserhastolearnishowtocreateandeditspatialdata.But,itisalsoasimportantastolearntheconceptofspatialdata.RememberthatinArcMap,ausercanmakeuseoftwotypesofdata,thespatialandthenonspatial.Nonspatialdataaredatathatisnotgeographicalintegrated,whichmeanthatinusingsuchkindofdatayouhavetoperformsomeoperations.Spatialdataontheotherhand,isalreadyapartofagraphicalrepresentationofanarea.Spatialdatacanbeintegratedintoaline/polyline,point,orpolygon.Withthatinformation,wheneverauserwillclickanyfeaturewithinamap(withtheuseofIdentify)ArcMapwillbeabletodisplayaddedinformationasincludedwithinthespatialdata.Spatialdataisalsotermedasgeospatialdataorgeographicinformation.Includedinthedataaregeographiclocationsoffeaturesandboundaries,coordinates,andtopology.MostlyspatialdataaretheoneneededforGISprocessing.

    DataAcquisitionsAcquiringspatialdatacanbedoneinmanyways.Thereiswhatwecalledasdigitizing,itistheprocesswhereaprintedmaphastobecapturedusingaphotoscannerandtheimagethatitproducedistracewithinArcMap.Anotheronestillwiththeuseofsketchingmethod,willbefromaerialphotographandtraceaswellwithinArcMap.Also,wecanacquirespatialdatabyactuallydoingasurvey.SurveyscanbedoneusingtheTotalStationorusingtheGlobalPositioningSystem(GPS).DatafromtheTotalStationortheGPSstillneedstobeprocessedinorderforittobeusedwithinArcMap.ThedatathathasbeengatheredwillthenbemanipulatedinorderforittobealignedwithanycoordinatesystemsandonanyexistingArcInfospatialdata.

    GISLaboratoryExercise4CreatingandEditingSpatialDataObjectives:Inthisexercise,youwill:

    - AlignanacquiredaerialphotousingGeoreferencing- CreatingandEditingspatialdatafromaerialphotograph- ImportingspatialdatafromCADfile

    UsingGeoreferencingtoalignanaerialphotograph

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  • Acquiringaspatialdatacanbedoneinmanyways.Withtheexistenceoftheinternet,wecanbeabletoacquireabundantsourcesofthesedata.Forthisportionoftheexercise,wewillutilizeanaerialphotoobtainedfromGoogleEarthprogram.

    o RunArcCatalog.

    o Makesurethatthefileextensionisvisible.Hint:ClickCustomizemenuandthenselectArcCatalogOptions.

    o ClicktheGeneraltabifnecessary,andmakesurethatFolderConnections(alwaysshown),Toolboxes,andReturntolastlocationwhenArcCatalogstartsuparetheonlyboxesthatshowsthechecksign.ThenclickOK.

    o VerifyLearnGIS2folderappearsonyourFolderConnections.Ifnot,thenyouhavetoaddLearnGIS2folder.

    o ExpandLearnGIS2andselectCreatingandEditingSpatialDatafolder.

    1. Whatarethefilesanditscorrespondingtypecontainedinthisfolder?________________________________________________________________________

    o ExpandCreatingandEditingSpatialDatafolder,rightclickonSRP_01.jpg,andselectPropertiesfromthepopupmenu.

    2. DoesthisRasterDatasetcontainanyspatialreference?____________________

    o ClosethePropertiesdialogboxandclickonthePreviewtab.

    3. DescribethecontentofSRP_01.jpg.________________________________________________________________________

    o CloseArcCatalogandrunArcMap.

    o InArcMap,clickFilemenuandselectOpen.LocateCebuCitySRP.mxdmapdocumentin..\LearnGIS2\CreatingandEditingSpatialDatafolderandclickOpen.

    YourcurrentviewistheSRPAreawhichisaviewbookmark.Currently,SRP(SouthRoadProperties)doesnotexistonthismap.ItisourobjectivetocreatethemapoftheSRP.Since

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  • theonlywaywecandothatistomakeuseofareferencemapwhichisanaerialphotoofthearea.

    o FromCatalog,locateSRP_01.jpganddragdropittotheDataFrame.

    o OntheCreatePyramidsforSRP_01.jpg(4000x2604)dialogbox,clickonYes.(IfadialogboxrelatedtoSpatialReferencewillappear,justclickOK).

    o ZoomtoFullExtent.

    4. Describewhathappened.Whatisthescaleofthemap?Canyouseetheimageandthe

    mapclearly?________________________________________________________________________________________________________________________________________________________________________________________________________________________

    o ZoomtoSRP_01.jpglayer.Hint:RightclickSRP_01.jpgandthenclickZoomToLayer.

    o UsingthemousescrollortheZoomOuttool,zoomouttheDataFrameuntilyoureachtheapproximatescalevalueofthefullextentview.

    5. Describetheactuallocationoftheimagewithrespecttothemap.________________________________________________________________________________________________________________________________________________

    o ClicktheFullExtentzoomtoolagain.

    o ClicktheCustomizemenuthenselectToolbarsandverifythatGeoreferencingischecked.

    o TheGeoreferencingtoolbar willappear.Dockittothetoolbararea.

    SinceGeoreferencingtoolwillworkonRasterandimportableformats,whatwouldonlyappearontheLayerdropdownlististheSRP_01.jpg.

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  • o ClickBookmarksmenuandselectSRPArea.

    o ClicktheGeoreferencingdropdownmenuandclickFitToDisplay.

    o ClickBookmarksmenuagainandselectRightMostPoint.Locateayellowcoloredcircleontheimagesimilartowhatisshownbelow.

    o ZoomtoFullExtent.FromtheTableOfContents,movetheSRP_01.jpgaboveBrgysOfCebuCitylayer.

    o ClickBookmarksagainandselectLeftMostPointtoviewtheleftmostpartoftheimageasshownbelow.

    o Thistime,clicktheBookmarksmenuandclickSRPArea.Takenotethatforthisexercisereferencepointsareheldoutforyoutomakesurethatyouwillbeabletoeasilylocateit.

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  • o PlacetheSRP_01.jpgbelowBrgysOfCebuCitylayeronceagain.

    o SetthetransparencyofBrgysOfCebuCityto75%.Hint:RightclickonBrgysOfCebuCitylayerandclickProperties.ClicktheDisplaytabontheLayerPropertiesdialogboxandtype75ontheTransparentfield.

    o ClickBookmarksmenuandselectLeftMostPoint.Besurethattheyellowdotontheimagewillbevisible,ifnecessaryzoominsomemore.

    o OntheGeoreferencingtool,uncheckAutoAdjust(clicktheGeoreferencingdropdownmenu)andthenclicktheAddControlPointsbutton .Clickonthecenteroftheyellowdotandsettheotherendpointofthelineatanintersectingroadjustaboveit.Verifyyourresultthroughthefollowinggraphic.

    o NowclicktheBookmarkmenuagainandselectRightMostPoint.o Clickonthecenteroftheyellowdotandsettheotherendpointofthelineatthetipofa

    polygonshapeasshownbelow.

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  • Thefirstprotrudingpolygononthisarea.

    o ClicktheGeoreferencingdropdownmenuandclickUpdateDisplay.Note:IncaseyouwillhavesomemistakesinusingtheAddControlPoints,justopentheLink

    TabledialogboxbyclickingtheViewLinkTable .OntheLinkTabledialogbox,youmaydeleteanyexistinglinksthatyouhavecreated.

    6. WhathappenedtotheimageontheDataFrame(UsethePantool toexaminethemap)?________________________________________________________________________

    o ClickUpdateGeoreferencingintheGeoreferencingtool.SaveyourmapasMyCebuCitySRPinyour..\MyGISOutputsfolder.

    o RemovetheGeoreferencingtoolfromyourtoolbar.Hint:RightclickontheemptyareaofthetoolbarforthepopupmenutoappearanduncheckGeoreferencing.

    CreatingaSpatialDatabysketchingtheaerialphotographThegeneraltermusedforanygeographiclayerwithinanyGISsoftwareisSpatialData.InArcMap10thisisspecificallycalledaFeatureClasswhileinolderArcGIS3itiscommonlyasShapefile.

    o ClickontheCatalogtoolandlocateCebu_City_SRPgeodatabase..\LearnGIS2\CreatingandEditingSpatialDatafolder.whichisin

    o RightclickonCebu_City_SRPgeodatabaseselectNewandthenclickFeatureClass.

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  • o OntheNewFeatureClassdialogbox,typeSRP_RoadsontheNamefieldandthenselect

    LineFeaturesunderType.ClickNexttocontinue.

    o Forthecoordinatesystemselection,clickonImport.OntheBrowseforCoordinateSystemdialogboxlocateandselectBrgysOfCebuCityfeatureclasswhichislocatedin..\LearnGIS2\CreatingandEditingSpatialData\Cebu_City_SRPgeodatabasethenclickAdd.VerifythatPhilippines_Zone_IVwillappearintheNamefield.ClickNextthrice.

    o UndertheFieldNamecolumn,onthethirdrowtypeRoad_NameandsettheDataTypeasTextthenclickonFinish.

    SRP_RoadslayerisnowbeingaddedtotheTableOfContents,butthislayerisstillemptythereforewewillplacesomefeaturesintothislayer.

    o RightclickontheemptyareaofthetoolbarandenabletheEditortool.DocktheEditortoolifnecessary.AlsoenabletheSnappingtoolanddockitifnecessary.

    o ClicktheEditordropdownmenuandclickStartEditingasshownbelow.

    o TheCreateFeaturesdockingwindownowappearedontherightsideofArcMap.SelecttheSRP_RoadsandontheConstructionToolsbesuretoselectLine.

    o ZoomtotheareaneartheFortSanPedroneartheMalacaansaSugboandbegintracingthemajorroadfromthatpoint.BesurethatUseSnappingisunchecked.VerifythisinSnappingtool.

    Whiledoingthetracingyoumightwanttopanorzoomthemapwithoutlosingthetracingmode.Youcandothatbyutilizingtheshortcutkeys.Inordertopanthemapwhileintracingmode,presstheCkeyandassoonasthecursorchangesintoahandsymbolwithoutreleasingtheCkeydragthemousetowhereyouwantthemaptobefocused.

    Forthezoomingoperationwhileontracingmode,justpresstheZkeyanddragaboxaroundtheareayouwanttozoomin.Justusethemousescrollifyouwanttozoominoroutwithoutspecifyinganarea.

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  • TospecifyanendtoasegmentjustclickonitandcontinuethetracinguntilyouarriveatthelocationoftheboundarybetweenTalisayandCebuCity.Wheneveryouarriveatthatpoint,rightclickandselectFinishSketchonthepopupmenu.Theroadshouldbemoreorlesslikelythesameasthefollowing.

    o Whiletheroadishighlighted,opentheattributesbyclickingtheAttributesbuttonon

    theEditortoolbar .OntheAttributesdockablewindow,settheRoad_NamefieldasCebuSouthCoastalRoad.

    o Next,wewilltracetheSRPMambalingRoadwhichiscompletelyshownbelow.(NametheroadontheAttributeswindowasSRPMambalingRoad)

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  • o ClickontheEditordropdownmenuandclickSaveEdits,thenStopEditing.

    o SettheSRP_RoadssymbolcolortoYuccaYellow(row1,column5)anditsWidthto2.

    ThistimewearegoingtocreatetheareawhichistheentireSRP.

    o Usingwhatyoulearnincreatingnewfeatureclass,createapolygonfeatureclassandnameitasSRP_Area.Forthefields,justprovidethefollowing:

    o FieldName:Area_NameDataType:Text

    o Usingwhatyoulearnwhenyouauthoredtheroads,starteditingthefeatureclass.

    7. OnCreateFeatureswindow,doe

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