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I host some raster data on geoserver and want to access all pixel values within a given area (e.g. a geojson polygon). I can access single pixel values via WMS GetFeatureInfo but this approach is limited to a single point, not areas.

WCS seems to work for area requests but the available operations don't serve the purpose of retrieving values.

Is there a way to run a WMS/WFS/WCS like request for raster data using an area as request?

Are cql filters a way to go?

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    What is wrong with the wcs requests? That's what it is for
    – Ian Turton
    Commented Feb 22, 2017 at 18:30
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    Sunsetting requests with WCS is the way to go if want actual values from rasters
    – nmtoken
    Commented Feb 22, 2017 at 23:37
  • Ok, I'll have a look at WCS again. I suspect you mean the GetCoverage operation? (I misunderstood the description, that's why I didn't consider it. thanks for pointing it out).
    – unnic
    Commented Feb 23, 2017 at 8:42
  • I can't find any examples where WCS is used in such a way. The documentation isn't much help either: docs.geoserver.org/stable/en/user/services/wcs/…. Can you maybe provide an example?
    – unnic
    Commented Feb 23, 2017 at 9:18

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WCS is the way to go, maybe you mean that you cannot read the output from its binary form? Try using the GML version then, this is an example request returning a 2x2 grid of values in GML format:

http://demo.geo-solutions.it/geoserver/wcs?service=WCS&version=2.0.0&request=GetCoverage&coverageId=nurc:Arc_Sample&format=application/gml%2Bxml&subset=Lat(40,41)&subset=Long(40,41)

For more information about the protocol, see the official spec documents: http://www.opengeospatial.org/standards/wcs

and in particular the KVP one: https://portal.opengeospatial.org/files/09-147r3

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  • Thanks for your answer. The format isn't the problem (yet, I need to read it in JavaScript later). I can't find any good documentation/examples on how I can run a WCS request in the way I described it above. E.g: how does the subset work? How can I subset with multiple points or a geojson?
    – unnic
    Commented Feb 23, 2017 at 9:13
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    No, you cannot perform extractions by polygon or set of points, only by bounding box. No OGC protocol supports out of the box what you want to do, but you can write a new WPS process to create support for it (java coding required)
    – Andrea Aime
    Commented Feb 23, 2017 at 9:23
  • ok, then I have to find another way. If you have any hints how I could go about this let me know. Thanks for your help
    – unnic
    Commented Feb 23, 2017 at 10:27

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