Query ImageServer to get DEM elevation value returns RGB values only

RussCoffey — Wed, 12 Jan 2011 20:17:06 GMT

I have a Silverlight 4 app that queries an ArcServer 10 ImageServer to retrieve an elevation value from a DEM for a user-specified point.

The app. worked at first. After a month of sitting untouched, it now returns RGB values instead of an elevation value, as shown below. The value for "value" used to come back as something like 2452.5 but now it looks like the stretched grayscale display color.

[INDENT][INDENT]{
"objectId" : 0,
"name" : "Pixel",
"value" : "94, 94, 94",
"location" :
{
"x" : 755500,
"y" : 26500020,
"spatialReference" : {
"wkid" : 3421
}
}, "properties" : null,
"catalogItems" : null,
"catalogItemVisibilities" : []
}[/INDENT][/INDENT]
The Image Service is based on a LayerFile that points to a single-band raster in SDE 10 which contains elevation values. Querying the LayerFile in ArcMap (with the Identify tool, for example) returns elevation values properly.

Here is the C# code for the query:
[INDENT][INDENT]ImageServiceIdentifyTask zFind = new ImageServiceIdentifyTask();
zFind.ExecuteCompleted += zFind_ExecuteCompleted;
zFind.Failed += zFind_Failed;
ImageServiceIdentifyParameters qParams = new ImageServiceIdentifyParameters();
qParams.Geometry = e.MapPoint;
zFind.Url = "http://arcserverdev/ArcGIS/rest/services/ETS/SoNev_DEM/ImageServer";
zFind.ExecuteAsync(qParams);[/INDENT][/INDENT]
Any suggestions on how to get it to return the elevation value?

Thanks for any help.

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Query ImageServer to get DEM elevation value returns RGB values only