straatvark

WMS Capabilities via Rest: MinScaleDenominator MaxScaleDenominator values

Discussion created by straatvark on Jan 30, 2012
Latest reply on Feb 2, 2012 by ytang-esristaff
Hi

When I add a ArcGIS WMS service endpoint to a REST service endpoint that have Min/Max scale values set, the scale limits are available as MinScaleDenominator & MaxScaleDenominator values in the GetCapabilities response - with slightly different values.

For example, 1:600000 in the REST service becomes 1:566964.285714 in the WMS service endpoint. If I add the same WMS into ArcMap, ArcMap has the intelligence to know the 'real' scale and convert it back to 1:599999.

It seems the projection has an effect: My REST service endpoint is in spatial reference 2157, while the WMS GetCapabilities response list the following options in this order:
<CRS>CRS:84</CRS>
<CRS>EPSG:4326</CRS>
<CRS>EPSG:2157</CRS>

Now, if i have a client that should do the same calculation to get the 'real' scale, the following questions pop up:

  • Is the order of the CRS's important in the WMS GetCapabilities response?

  • How does ArcMap know that the actual spatial reference is 2157?

  • What is the calculation ArcMap do calculate 599999?

Any response would be appreciated,
regards, gert

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