GIS Tutorial for Health. Wilpen L. Gorr

5, you will learn how to combine multiple fields using a field calculator.

      Sort a single field

      1 In the Breast Cancer Deaths by County attribute table, right-click the CWFBF00_04 field name and click Sort Descending. This sorts the table from the largest number to the smallest number of breast cancer deaths for all females in each US county from 2000 to 2004.

      Select the counties with the highest counts of breast cancer

      Now that you have prepared the attribute table to sort by the highest number of breast cancer deaths, you can select records to isolate top cancer counties on the map.

      1 In the Breast Cancer Deaths by County table, press CTRL and click the row selectors for the first five records in descending order. Notice that the corresponding features are highlighted on the map. The areas selected as having the highest number of breast cancer deaths might not be surprising because these are some of the most populated counties in the country.

      Select the counties with the highest breast cancer rates

      A better indicator of breast cancer is the mortality rate per county.

       1 In the Breast Cancer Deaths by County attribute table, right-click the RWF00_04 field name and click Sort Descending.

      2 Press CTRL and click the row selectors for the first five records in descending order. Notice that the corresponding features highlighted on the map for the rate of breast cancer deaths for white females are much different from those for the highest count of breast cancer deaths for white females. (See facing page.)

      YOUR TURN

      Find the counties that had the highest rates of breast cancer deaths from 2000 to 2004 for black females. Clear your selections when you are finished.

      Sort multiple fields

      Sorting by the number of cancer deaths was useful for finding the counties that had the highest number of breast cancer deaths and death rates across the United States, but what if you wanted to examine the number of deaths for one state? To do this, you would need to sort the records by two fields: state and number of deaths.

       1 Right-click the STATE_NAME field and click Advanced Sorting.

      2 In the Advanced Table Sorting dialog box, click the “Sort by” arrow, select STATE_NAME, and select the Ascending option if it is not already selected. This sets up the first sort order to sort alphabetically by state.

      3 In the Advanced Table Sorting dialog box, click the “Then sort by” arrow, select CWFBF00_04, and select the Descending option. Click OK. This sets up the second sort order to sort for highest-to-lowest female deaths between 2000 and 2004.

       4 Scroll through the list until you find the records for Texas.

      5 Select the first five records for Texas. This selects the five counties that had the highest number of breast cancer deaths for all females.

       6 Close the attribute table.

      7 Click Bookmarks > Texas or zoom to Texas. The resulting map shows the locations of the five counties that had the highest number of female breast cancer deaths in Texas. (See facing page.)

      Show only selected records

      1 Open the Breast Cancer Deaths by County attribute table and click the “Show selected records” button . This shows the records for only the features selected in the map.

       2 Click the “Show all records” button to show all records again.

       3 Close the attribute table.

      Save the map document

       1 On the Menu bar, click File > Save As.

      2 Save your map document as Tutorial2-7YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.

Tutorial 2-8

      Creating a new layer of a subset of features

      Sometimes just a subset of features is needed in a map layer. For example, in this tutorial, you will create a layer that has the counties you just selected.

      1 Right-click the Breast Cancer Deaths by County layer and click Selection > Create Layer From Selected Features. This adds a new layer to the table of contents that contains just the five counties in Texas that had the highest number of breast cancer deaths.

       2 Rename the new layer Top 5 Texas Counties, Female Breast Cancer Deaths 2000-2004 and change the color fill to Mars Red.

      3 Drag the new layer below Major U.S. Cities and clear the selected features. The resulting map clearly shows the Texas counties that had the highest number of female breast cancer deaths between 2000 and 2004.

      Save the map document

       1 On the Menu bar, click File > Save As.

      2 Save your map document as Tutorial2-8YourName.mxd to your Chapter2 folder in MyExercises. Do not close ArcMap.

Tutorial 2-9

      Creating a point map based on a definition query

      Sometimes just a subset of features is needed in a map layer. Suppose you have a layer that contains all the cities in the United States, but you want to display only the cities in Texas that have a population over 600,000. To do this, you can create a definition query to filter out all the cities that have population values outside the desired range but keep those that are in Texas in the desired range.