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You can request geography-level shading on map images to show information such as income or population. This can be done in three ways, depending on what you want to show in your map.
Do this by using the basic method getThematicMap with the parameter thematicField. Use the method getThematicFields for list of available thematic field names, use the method getThematicGeographiesForExtent for a list of available geographies, and use the parameter thematicField to set the thematic field you want to use to color your map. Use the other optional parameters to define class breaks and color. See Thematic variables for descriptions of the thematic field names
Do this by using the user-defined method getThematicMap with the parameter thematicData. Use the thematicData parameter to define the relationship between geographic regions and data. Use the other optional parameters to define class breaks and color. For example, if you wanted to pair a ZIP Code with a numeric value, you could use:
thematicData
parameter:
key = 92373
value = 5
Do this by using the user-defined method getThematicMap with the parameter thematicData. Use the thematicData parameter to define the relationship between geographic regions and data . Then use KeyValue to define the relationship between data and color. For example, if you wanted to pair a ZIP Codes with a numeric values, then later set that the values to have a particular RGB color, you could use:
thematicData
parameter:
key = 92373
value = esri
key = 92374
value = not esri
key = 92371
value = not esri
colorCodeValues parameter (part of ThematicOptions
object):
key = esri
value = 255,0,0
key = not esri
value = 0,255,0
Geographic codes for thematic mapping
The parameter thematicData in the user-defined method getThematicMap requires a geographic code that includes all the geographies up to and including the most specific one desired. For example, the code for a county is 5-digits in length (e.g., 06073) because it includes a two-digit state code (e.g., 06) plus a three-digit county code (e.g., 073). The block group code is 12 digits long (e.g., 060730091034) because it includes all of the following regions:
STATE_FIPS (2 digits -- 06)
COUNTY_FIPS (3 digits -- 073)
TRACT_CODE (4 digits -- 0091)
TRACT_SUFFIX (2 digits -- 03)
BLOCK_GROUP (1 digit -- 4)
The geographic codes can be found with Query Web Service, using the method getAvailableFieldNames and the dataSource ESRI.Thematic.US.
GDT.PopulatedPlaces.US does not include leading zeros in the fields COUNTY_FIPS or STATE_FIPS (i.e., 6 instead of 06). Be sure to have the correct number of digits in any request that requires FIPS codes, e.g., user-defined method getThematicMap in Map Image Web Service.
GDT, NAVTEQ, and Tele Atlas street data is available in stylized looks to help create a customized look for your Web application. Not all styles are available with each data source and some advanced mapping functionality is not available with ExpressMap. Click a map style name to see a graphic example and metadata information. See Data sources and credits for a complete list of which data sources support which map styles.
Imagery data sources are best viewed as JPEG files
Data sources that present imagery content, such as Pixxures.DOQQ.US and NGS.Topo.US, look best when the file format is JPEG.
The PixelCoord object is a location in pixels on a map image. For example, if you have a map that is 400x400 pixels, the map's upper left pixel is the PixelCoord (0,0) and the upper right pixel is the PixelCoord (399,0).
Map Image supports English for overview data and the native language of the country for detailed data.