Join location from another layer pivot tablePresentation Transcript
O IN L J IA AT SP Spatial Join Calculating Number of Physician per Population 2 GIS in Health and Planning 2 01 1/ 2012 Spring3/ Rutgers University by Wansoo Im, Ph.D.
Download census tract 2000 file-www.state.nj.us/dep/gisDownload Municipal boundaries-https://njgin.state.nj.us“doctor point location layer” (downlaod from Sakai )Census tract map/Municipality boundaries=>Add All Maps in Arc GIS
CENSUS TRACT : OPEN ATTRIBUTE TABLEIn order to see what kind of information it has
DOCTOR LOCATION LAYER : OPEN ATTRIBUTE TABLEIn order to see what kind of information it has
HOW TO JOIN LOCATIONAL DATA WITH DATA FROMANOTHER LAYER?Based on the location, we will join doctor’s location into Census tract layer.
JOIN DOCTOR POINTS WITH CENSUS DATA LAYER
CLICK “DATA FROM ANOTHER LAYER BASED ONSPATIAL LOCATION”
SELECT “THE LAYER(CENSUS TRACT)” WHICH YOUWANT TO JOIN WITH DOCTOR LOCATION
SET THE DIRECTORY(LOCATION TO SAVE YOURSHAPEFILE) -> CLICK “SHAPEFILE”
OPEN ATTRIBUTE TABLE TO CHECK IF NEWLAYER(DOCTOR CTR) IS SUCCESSFULLY JOINTBy opening attribute table, you can check if data from 2 original layers(doctor points/census tract information) are included into a newly-created shapefiles.
LOOK THROUGH DATA
EXCEL – PIVOT TABLEObjectives :We are going to export data from maps into dbf.(dbf. File includes the information of table, therefore, all shapefiles including data in the table have dbf. file)Open dbf. File in ExcelBy using Pivot table, we will calculate the number of doctors by each census tract(the number of doctors belonging to each census tract)
OPEN ATTRIBUTE TABLE OF DOC_CTR LAYERClick the menu icon to export data from table.
EXPORT DATA “DBF. FORMAT FILE”
WHY WE EXPORT DATA FROM TABLE?(DBF. FORMAT) Originally Doc_CTR shapefile already has one dbf.file, however, if we start to open it in the excel and modify, we can possibly affect the original map data as the table is directly linked to a map. Therefore, we would like to export data from the original table so as to create new dbf. File(so to speak, “copy” dbf. file). In this way, we can adjust data(by using a new dbf. File) in Excel regardless of affecting original data in the map.
OPEN -> CLICK “ALL FILES”-> CLICK “DBF FILE”
OPEN IN EXCEL
WE CAN USE EXCEL FOR DATA CALCULATION!
THE NUMBER OF DOCTORS WITHIN EACH OF CENSUSTRACT.Number of doctors in each of census tract.How do we calculate?
USE UNIQUE ID TO JOIN “INDIVIDUAL DOCTOR LOCATION” WITHIN CENSUS TRACT – “KEY” FIELD OR “STFID” (CENSUS TRACT ID)Why can’t we use Tract field? – Tract id is within County (Aggregate scale)
CLICK “INSERT” -> PIVOT TABLE
CLICK “PIVOT TABLE”
THEN YOU WILL SEE THIS TABLE ;
DRAG “STFID” INTO ROW LABELS
DRAG “STFID” INTO VALUES
COPY THE TABLE
PASTE “VALUE” INTO NEW “SHEET”Counting Case depending on variable that you chose.In this case, Fivot Table counts the number of doctors depending on the Census Tract Area(Assigned by unique ID).
CLEAN THE DATA – FIRST ROW SHOULD INDICATETHE NAME OF FIELD
CLEAN THE DATA – DELETE LAST ROW ; TOTALNUMBER
CHANGE “SHEET” NAME INTO DATAName that you can rememberNo space/No special characters(Arc GIS cannot recognize)
SAVE EXCEL FILE AND CLOSE ITBEFORE JOINING IN ARC GIS PROGRAM
CENSUS TRACT LAYER- OPEN ATTRIBUTE BEFOREJOINING DATA
JOIN THE TABLE
JOIN ATTRIBUTE FROM A TABLE
SELECT THE FIELD TO JOIN “STFID”(UNIQUE CENSUS TRACT ID)
CLICK EXCEL FILE YOU SAVED
CLICK THE “SHEET” THAT YOU SAVED NEW DATA(NO.DOCTORS BY CENSUS TRACT)
SELECT THE FIELD(STFID) FROM “DATA SHEET”
CHECK ATTRIBUTE TABLE TO MAKE SURE IF TABLE ISJOINT WELLThere are some null data because this census tract is statewide while doctor location is located only within Middlesex county.
CALCULATE THE NUMBER OF DOCTORS PERPOPULATION WITHIN CENSUS TRACTThe number of doctorThe number of populationLet’s calculate doctors per population.
ADD A NEW FIELD
ADD FIELD10 digit/3decimal
CREATE NEW FIELD (FOR DOCTORS/POPULATION)->RIGHT CLICK TO DO “FIELD CALCULATING”
FIELD CALCULATORBut you will have 0 if denominator(total population2000=0) is 0Select the data which population 2000 is more than 0Use Field Calculator to use formula (number of doctors/population*100)
2 WAYS FOR SELECTION1. Select by Attribute select the layer “census 2000”, and select the field “population2000” put formulaPop2000>0 ->click apply2. Sorting Ascending in Attribute TableOpen Attribute table, sort the data regarding population 2000, and select data which is more than 0 in population 2000 field.
EX1) SELECTION BY SORTING POPULATION
EX2) SELECTION BY MENU (SELECTING BYATTRIBUTE)Make sure if Population(denominator) is 0 not
RATE CALCULATION– WHY 1000? INSTEAD 100?
IF THERE’S NULL DATA => ERROR!!!Population should be over 0 ANDNumber of doctors shouldn’t be null dataTherefore, number of doctor is more than 0 and calculate it again(Assume that if there’s doctor, population is over 0)
YOU WILL GET NO.DOCTORS PER POPULATIONPERCENTAGE IN NEW FIELD YOU CREATED.
GO TO SYMBOLOGY AND MAP IT OUT!The number of doctors per population
EXPORT MIDDLESEX MUNICIPALITY FROM CENSUSTRACT
SELECT MUNICIPAL OF MIDDLESEX COUNTY
EXPORT MIDDLESEX COUNTY CENSUS TRACTField : Double click “County”Click “Unique valueCounty= Middlesex county
CHANGE DECIMAL DEGEE IN LEGEND-> CLICK “LABEL” AND “FORMAT LABEL” CHANGE DECIMALDEGREE.
EXPORT MUNICIPAL BOUNDARY SHAPEFILE.County = Middle sex