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Problem: ArcIMS services are displayed in wrong coordinate space in ArcMap if map units are incorrect

Description

The MAPUNITS tag in ArcXML describes the map units of the data. The default value for this tag in ArcIMS Author and ArcExplorer Java (AEJ) is decimal degrees, even if the data is projected and has a projection file.

If the Map units for a service are not manually set to be the same as the data's coordinate system units, the ArcIMS layer will not be displayed in the correct coordinate space in ArcMap.

For example: An ArcIMS service uses data that has been projected in Lambert. The data's actual map units are meters, but the MAUPUNITS tag in the service axl file is set to decimal degrees by default. The service will not work correctly in ArcGIS.

Cause

Neither ArcIMS Author nor ArcExplorer Java automatically sets the MAPUNITS based on the projection file.

ArcGIS assumes the spatial reference for a service with map units of decimal degrees is Geographic.

Solution or Workaround

There are two possible solutions:

  • In ArcIMS Author or ArcExplorer Java, click View, point to Scale Bar Properties, point to Map Units, and point to the units that match the data's coordinate system units.
    Save the project.
  • Open the ArcIMS service axl file in a text editor such as Notepad. Find the MAPUNITS tag (within the PROPERTIES tag of the MAP tag). Replace the units string value of decimal_degrees with feet or meters depending upon the coordinate system units of the data.