In this lab, we will download a 2000
census tract shapefile and 2000 population data by
census tracts. After a projection is assigned to the shapefile,
the population data will be joined to the file. For our analysis, we will
calculate the population around three
Download the hospitals.zip file into your My Documents folder. Richt-click on the file and Extract To: Hospitals.
1. Click on this link to get
to the ESRI tiger data site: http://arcdata.esri.com/data/tiger2000/tiger_download.cfm
2. Select
3. Check the Census Tracts 2000 box and click the Proceed
to Download on the bottom of the screen and next, click the Download
File button.
4. Download the file as 2000tracts and extract (right-click)
it to your folder in My Documents using Enzip. Double-click
into the folder that has been created and extract this zip-file same folder (to here). Leave it
there for right now, we will project this file later.
1. Click on this link http://www.census.gov/
2. Click on American FactFinder and then Data
Sets links located on the left-hand side of the screen.
3. Census 2000 Summary File 1 (SF1) is already selected so click
on the Detailed Tables link located on the right-hand side of the
screen
4. From the dropdown menus choose for geographic type Census Tract.
Select the state
5. Select P1. Total Population and click Add. Click the Show
Result button.
6. From the Print/Download menu choose Download and in the next
screen select Microsoft Excel (.xls)
format (scroll down) and click OK.
7. Download the file as 2000tracts.zip file to you’re
my Documents folder and extract all files to: 2000poptracts.
8. Open both files in Excel.
The table dt_dec_2000sf1_u_geo contains the tract number, and the dt_dec_2000sf1_u_data1
table contains the population numbers.
9. Delete row 2 in the data file. Copy the column with the population
data (P001001).
10. Paste the column into the geo file, next to the tract column.
11. Save the geo file as 2000poptracts.xls.
1. Open ArcCatalog
and browse to your folder in MyDocuments.
2. Create a personal geodatabase named popcounts.
3. Go to the Windows My Documents folder and double-click on the popcounts.mdb
to open the database in Microsoft Access. If a security warning comes up, click
Open.
4. Now we are going to import the excel file as a table. Click
File > Get External Data > Import. Choose *.xls as files of type. Browse to your folder in My Documents
and select the 2000poptracts.xls file and import it.
5. In the import dialog check First Row Contains Column Headings, click
next and again next. Then select No primary key in the fourth step. Type in 2000poptracts in the Import to Table field.
This will be the name of your table. Click Finish and OK to the
import message.
6. Open the table to check whether the import worked.
1. Open ArcMap
and add the 2000tracts shapefile.
2. Rename the layer to 2000tracts.
3. Select this file in ArcCatalog and click on
the Metadata tab. Then select the spatial tab. The following is
listed under the Horizontal coordinate system: Geographic coordinate system
name: GCS_Aussumend_Geographic1. ArcGIS
attempts to determine the shapefile's coordinate
system based on the dataset's coordinate values. In this case, ArcGIS has determined that the shapefile
is in geographic coordinates - latitude, longitude - however, you need to
explicitly define the geographic coordinate system before you can project the
data.
4. Open the ArcToolbox.
5. Click on Data Management Tools > Projections and Transformations
> Raster and double-click Define Projection to open the
define projection dialog.
6. With this step, we are going to assign a geoid to
the data. For the Input Dataset and Feature class click on the drop-down
arrow and choose the 2000tracts layer. ArcGIS
automatically puts the assumed projection in the coordinate system box. Click
on the paper hand and click the select button on the next dialog.
Go into the Geographic Coordinate Systems >
When you define a coordinate system, you simply tell ArcGIS what projection the dataset uses and what units the coordinates are stored in. When you project a dataset, on the other hand, ArcGIS actually creates a new dataset with the coordinates transformed from the existing coordinate units, in this case, decimal degrees, to a new coordinate system, in this case, Transverse Mercator (UTM) meters. You specify the input dataset and the coordinate system to project into, and ArGIS creates the new dataset.
1.In the ArcToolbox, click Data
Management Tools > Projections and Transformations >
Feature and open the Project tool.
2. In the Input Dataset and Feature class box select the 2000tracts
layer. Click on the folder icon next to the Output Dataset and Feature class, browse to My
Documents and save the file as 2000tractsproj. Click on the paper hand next
to the output coordinate system box and click select in the menu that shows up.
Go to Projected Coordinate Systems > UTM > NAD 1983
and select NAD 1983 UTM Zone 14N.prj.
3. Click Add, OK, and OK to assign the projection.
1. Add the new 2000poptracts table
which is in the popcounts geodatabase
to the map.
2. Right-click on the 2000tractsproj layer and point to Joins and Relates
and click on Join. Base the join on TRT2000 of this layer and
choose the 2000poptracts layer and its column TRACT.
3. Click OK and Yes to indexing.
4. Open the 2000tractsproj attribute table to check out whether the join
worked. The population column (P001001) should now be visible in the
2000tractsproj table. If you are not able to open the attributes table and an
error message shows up do the following step:
4.1. Right-click on the 2000poptracts layer and point to
Data. Click on Export Data.
4.2. Save the file
in your directory as 2000poptracts2.shp.
4.3. Add the layer to your map.
4.4. We now created a new layer that incorporates our
population data in its attribute table. It is no longer only joined.
5. Map out the total population (layer properties > Symbology > Quantities > Value: P001001). Also flip
the symbols, reverse the sorting, and assign 0 decimals to the labeling of the
numbers (do right-clicks in order to get to the respective menus).
In this part, we are going to select census tracts that intersect the hospitals within a 1000 meter radius. Then we are going to have a look at the population the different hospitals are serving.
1. Add the three hospitals
we downloaded earlier to your ArcMap project.
2. Right-click on the layers data frame set and open
the properties. Go to the General tab and set the Display
Units to Meters. Click OK to the error message.
3. Go to Selection > Select by location. Choose “I want to: select
features from the following layers:” 2000tractsproj that: are
within a distance of: stjoseph of 1000
Meters. Click apply to select the tracts that
intersect within a 1 km range to
4. Open the attribute table of the 2000tractsproj layer and right-click
on the population column. Select Statistics and write down the
number of people living in the selected tracts. Clear the selection.
5. Repeat steps 3 and 4 for the other two hospitals.
We are going to create two maps. The first
is going to depict the selection of the tracts surrounding all three hospitals
within a 1000 meter radius and listing the population you wrote down earlier
for each hospital. The second map shows the selected census tracts of a
selection radius of 2000 meters and also the population numbers.
1. Map 1: In order to get a selection of all three hospitals, repeat the
selection steps while selecting all three hospitals in the "I want to:
select features from the following layers:" menu. Create an extra
textbox to put in the population each hospital is serving. Export
the map as a pdf, submit it to your public_html folder in Myfolder,
and link it to your index.html.
2. Map 2: Repeat the single selection with a selection radius of 2000 meters
and write down the population (step 4 of selecting the tracts). Then
create a layout with all tracts of all hospitals selected (as described in step
1 of creating a layout). Export the map as a pdf,
submit it to your public_html folder in Myfolder, and link it to your index.html.
Lab created by Eva Grund, October 2005.