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Having used WMS for years now, I am wondering what extra benefits there could be if I also offered WCS for certain raster datasets eg. DEM.

I have geotiff DEMs which I have loaded into geoserver and the height value is readable by WMS-getFeatureInfo. If I displayed this as a wcs what would I gain?

thanks for any help,

Rob

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1 Answer 1

A WCS returns the data rather than a picture of the data (which a WMS does), it could be thought of as a WFS for rasters.

So you need to ask do you need to process the data or just look at it?

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Thanks. I understand what wcs does, but I´m not sure on why I should implement it instead of wms. I have already uploaded a GeoTiff DEM to geoserver. The Geotiff has a value field which contains heights. Using OpenLayers - when I use getFeatureInfo the height field is diplayed. As far as I understand, the wcs would do exactly the same, wouldn´t it. I don´t want to geoprocess anything, just read the height values. –  Robert Buckley Aug 15 '12 at 5:52
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No, what would happen if you used the WMS service is that GeoServer would squeeze and quantize the height values into the range 0-255 so it can be displayed as a greyscale bitmap; you would lose all the data you'd need to reconstruct the values, and lose actual values if your height range is > 255. With WCS, you get the actual height values as (usually) a GeoTIFF, and it would be up to your GIS to render it as a greyscale or whatever colour ramp you choose. You may be lucky with your existing DEMs if they're 1m vertical res., and never go above 255m (replace m with the unit of your choice). –  MerseyViking Aug 15 '12 at 10:49

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