[mapserver-users] WCS GetCoverage request one by one pixel

[Bakker, Anton]

Hi Jukka,

Thanks for your response; do you mean to set the default resampling method in the mapfile? Setting the resampling method in the WCS request does not work (for both GET and POST requests):

POST:
<?xml version="1.0" encoding="UTF-8"?>
<wcs:GetCoverage
  xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
  xsi:schemaLocation="http://www.opengis.net/wcs/2.0
    http://schemas.opengis.net/wcs/2.0/wcsAll.xsd"
  xmlns="http://www.opengis.net/wcs/2.0"
  xmlns:wcs="http://www.opengis.net/wcs/2.0"
  xmlns:wcscrs="http://www.opengis.net/wcs/crs/1.0"
  xmlns:scal="http://www.opengis.net/wcs/scaling/1.0"
  xmlns:int="http://www.opengis.net/wcs/interpolation/1.0"
  service="WCS"
  version="2.0.1">
    <wcs:CoverageId>ahn3_05m_dsm</wcs:CoverageId>
    <wcs:DimensionTrim>
        <wcs:Dimension>x</wcs:Dimension>
        <wcs:TrimLow>196396.75</wcs:TrimLow>
        <wcs:TrimHigh>196396.75</wcs:TrimHigh>
    </wcs:DimensionTrim>
    <wcs:DimensionTrim>
        <wcs:Dimension>y</wcs:Dimension>
        <wcs:TrimLow>450031.75</wcs:TrimLow>
        <wcs:TrimHigh>450031.75</wcs:TrimHigh>
    </wcs:DimensionTrim>
    <wcs:format>image/tiff</wcs:format>
    <wcs:Extension>
        <int:Interpolation>
            <int:globalInterpolation>NEAREST</int:globalInterpolation>
        </int:Interpolation>
    </wcs:Extension>
</wcs:GetCoverage>

GET:

https://geodata.nationaalgeoregister.nl/ahn3/wcs?service=WCS&Request=GetCoverage&version=2.0.1&CoverageId=ahn3_05m_dsm&format=image/tiff&subset=x(196396.75,196396.75)&subset=y(450031.75,450031.75)&INTERPOLATION=NEAREST

Both POST and GET request fail with the same error: "msImageCreate(): Image handling error. Attempt to allocate raw image failed, out of memory."

Cheers,
Anton

________________________________
From: Rahkonen Jukka (MML) <jukka.rahkonen at maanmittauslaitos.fi<mailto:jukka.rahkonen at maanmittauslaitos.fi>>
Sent: Monday, April 6, 2020 5:26 PM
To: Bakker, Anton <Anton.Bakker at kadaster.nl<mailto:Anton.Bakker at kadaster.nl>>; mapserver-users at lists.osgeo.org<mailto:mapserver-users at lists.osgeo.org> <mapserver-users at lists.osgeo.org<mailto:mapserver-users at lists.osgeo.org>>
Subject: Re: WCS GetCoverage request one by one pixel


Hi,



Could you have a try with the default resampling "nearest"? And then also with subset having lower limit equal to upper. Now it fails, I tried already.



https://geodata.nationaalgeoregister.nl/ahn3/wcs?service=WCS&Request=GetCoverage&version=2.0.1&CoverageId=ahn3_05m_dsm&format=image/tiff&subset=x(196396.75,196396.75)&subset=y(450031.75,450031.75)



GetCoverage trim with equal low and high has at least worked in the past, see http://osgeo-org.1560.x6.nabble.com/Why-WCS-2-0-1-slice-is-not-supported-td5343277.html



It should be OK by the WCS standard because all intersected pixels should be included and in this case the intersection is a single pixel. But see also https://osgeo-org.atlassian.net/browse/GEOS-9553 and learn that Geoserver supports slicing but not trimming to one pixel.



-Jukka Rahkonen-


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