U.S. Census Bureau

Thematic Mapping

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The Thematic Mapping function allows the user to choose a data set and display it on a map using one of four color schemes and a solid or patterned fill. For example, you can display Age or Race data for counties in a range of colors.

When you first enter the Census 2000 Demographic Profiles database in LandView®, choose the geographic entity at which you would like to see the data displayed by clicking on the appropriate tab i.e. Counties or Census Tracts etc. In order to look at data for counties in Maryland for example, click on the Counties tab and then click the Setup A Find button. Once the Find screen appears, enter the state abbreviation in the field box labeled State and click on the Find button to the left of the screen.

With the expansion of data available in LandView 6, an appropriate data field can be selected from any of the four DP tables. In the appropriate DP table for Maryland Counties, place the cursor in either the number or the percent field box next to a data item of interest. Boxes marked with a percent sign, will be calculated based on the percentage. If you are not looking for a result based on the percentage, then click in the number field box. Once you have highlighted the appropriate field box you can then click on the Thematic Map button. If you do not select a data item, the following message will pop up-You must first click on a numeric field before performing this procedure.

Once at the Thematic Map screen, a set of four number ranges should appear. (In some instances this may not be the case.) The system determines the values of the selected data item by choosing number ranges that approximate an even distribution of records among the four or less categories. (Note that it may take the system a little time to process a large number of records.)

If you wish to change the quartile values, clicking on a number under To or From will highlight the number ranges and allow you to enter your own ranges. Click Recalculate Record Count when you are done. This will allow the system to redistribute the records. If you want to change the title, then simply click on that area of the screen and a text box will be displayed so that a change can be made.

There are four color schemes to choose from to display the map, as well as a choice of a solid or patterned fill. Once you have your display pattern and number ranges set, select Show on Map and a map will be displayed in MARPLOT®.

To cancel the thematic map, go back to LandView and click the Cancel button in the thematic map window. This will bring you back to the Census database. If you go back into MARPLOT after canceling the map in LandView, MARPLOT will return to its normal way of displaying objects.

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