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Mapping Options Summary

Select the options you want and click any button to see the map(s) you've selected. Click the button to change all options back to their default values.

Map Selection
Map Appearance
Category Break Control
Results Information
Printing Tips


Step 1. Select Map(s) to create:

This section allows you to select maps to create, depending on the information available for the current request.

Locations allows you to pick which locations to map.

Measures allows you to pick which measures to map.

Other By-Variables allows you to pick values for any by-variables other than geographic locations that were part of your request.

You can pick one or more item from each list. Each unique combination of one item from each list will result in one map being created. For example, suppose you have these options presented:

Locations: Georgia, Ohio
Measures: Death Count, Rate
Age Groups: 20-24 years, 25-29 years, 30-34 years

If you picked both states, Count, and 20-24 years you'd get two maps:

1. Georgia, Death Count, 20-24 years
2. Ohio, Death Count, 20-24 years
If you picked Georgia, Death Count and Rate, 25-29 and 30-34 you'd get four maps:
1. Georgia, Death Count, 25-29 years
2. Georgia, Death Count, 30-34 years
3. Georgia, Rate, 25-29 years
4. Georgia, Rate, 30-34 years

Step 2. Control map appearance:

This section allows you to control the "look" of the map, by selecting features shown on the map.

Height in Pixels allows you to change the size of the maps returned. There is an upper limit on size that can be returned. The size ceiling is normally around a value of 1000, but may vary depending on the particular geographical region that is mapped. The width of the map is automatically determined by the mapping service.

Color Scheme allows you to select a set of colors that are used in the map.

Labels allows you to put different labels on the geographical items that are mapped. You can put the name or code of the geographical entities on the map, e.g. county names. You can also show the measure values. You can display the actual measure mapped or any other measure that was returned with your WONDER query results.

Geography Year allows you to pick the year of geography codeset and shape files to use in your maps. The values available depend on the data being mapped. Most data currently available in WONDER only has a need for one geographic codeset. Counties, which have changed over time, are available for 1980, 1990 and 2000. Consult the documentation for individual datasets for more information about how geographic codes relate to that dataset.

Zoom in to Smallest Extent allows you to focus the mapped area on the places with data. For example, if you request data only for cities or counties that are near each other, and then select to "zoom in," then the map shows the smallest surrounding area boundaries rather than showing the entire nation.

Precision allows you to change the number of decimal values that display in the legend and on labels placed on geographic items. It doesn't affect the display of measures that are whole numbers. If all measures available to be mapped are whole numbers this option is disabled.

Show Interstates allows you to turn on and off the display of interstate roads on your map.

Note: interstate roads do not appear at certain small pixel sizes set in the "Height in pixels" control.

Show Rivers allows you to turn on and off the display of rivers.

Map Title allows you to add a title that just appears on the Maps page.

New Page Each Map causes each map to start on a new page when this page is printed, which can help to keep the parts of maps together on the same page.


Step 3. Control category breaks:

This section allows you to control how many separate categories the data shows when mapped. The first part of this section offers options where the system automatically calculates where to put the category breaks. The second part of this section lets you manually enter category breaks.

You can choose one option or the other, but not both. The option used is determined by which of the following buttons is selected:

Either select these category options...    enables automatic category breaks.
...or set your own category break points    enables manual category breaks.

As you set options in this section the correct button will be selected automatically if JavaScript is enabled in your browser. By default automatic category breaks are enabled.

Automatic Category Breaks

Categories allows you to select the number of groups shown in the mapped data. For example, if you pick Four, which is the default, your map has four different colors because the geographical entities were separated into four groups.

Category Breaks Method allows you to control how the categories are defined.

Equal Interval sets the ranges for the category breaks to an equal size. For example, if the mapped data ranges from 0 to 1000, then each equal category represents data ranges of 250. Using this method it's not uncommon for a majority of the mapped geographical entities to appear in just a few categories, since data points are often not evenly spaced across the range of values.

Quantile, the default, sets each category to contain the same percentage of geographical entities. This method results in an even distribution of mapped entities across the different categories.

Manual Category Breaks

Set your own category breaks by specifying a minimum and maximum value for each category desired. If you leave any gaps in your coverage of the data ranges, so that the ranges are discontinuous, then some entities may not map to a color, but instead map to the color matching "Other" in the legend.

To make your categories continuous set the minimum of each category equal to the maximum of the previous category. The value of the minimum field isn't actually included in the category, anything greater than it is.




This page last reviewed: Friday, June 26, 2009
This information is provided as technical reference material. Please contact us at cwus@cdc.gov to request a simple text version of this document.