[mapserver-users] WCS layer units question...

[Rahkonen Jukka (MML)]

Hi,

Sorry, I thought that our service is open. This should work https://demo.mapserver.org/cgi-bin/wcs?SERVICE=wcs&VERSION=2.0.0&REQUEST=DescribeCoverage&COVERAGEID=modis

The default value of uom is documented in https://www.mapserver.org/ogc/wcs_server.html
“If no specific or default value is given, the output is dependent on the metadata key. The UOM, for example will be set to ‘W.m-2.Sr-1’”

WCS metadata keywords, including “{band_name}_band_uom” work for us. I am sure that you will make it to work as well but if you won’t, show us your mapfile.

-Jukka Rahkonen-


Lähettäjä: MapServer-users <mapserver-users-bounces at lists.osgeo.org> Puolesta Carl Godkin
Lähetetty: keskiviikko 12. tammikuuta 2022 17.13
Vastaanottaja: Mapserver-Users (mapserver-users at lists.osgeo.org) <mapserver-users at lists.osgeo.org>
Aihe: Re: [mapserver-users] WCS layer units question...

Thanks for the reply, Jukka.

I found "wcs_band_uom" in the docs but I can't seem to make the value I put into my map file appear in the DescribeCoverage output.  (The link you sent doesn't work for me.)

I do see this though:

<swe:field name="band">
<swe:Quantity>
<swe:nilValues/>
<swe:uom code="W.m-2.Sr-1"/>
<swe:constraint>
<swe:AllowedValues>
<swe:interval>-3.4028e+38 3.4028e+38</swe:interval>
<swe:significantFigures>12</swe:significantFigures>
</swe:AllowedValues>
</swe:constraint>
</swe:Quantity>
</swe:field>

The "swe:uom code" would seem to be what I want to affect.  For some reason I see the value "watts per square meter per steradian" which appears nowhere in my map file so I wonder if it's some sort of default baked into the code or something.  (I had seen that before but hadn't bothered to try to figure out what it was until just now.  That's weird.)

Thanks for your help,

carl



On Tue, Jan 11, 2022 at 11:57 PM Rahkonen Jukka (MML) <jukka.rahkonen at maanmittauslaitos.fi<mailto:jukka.rahkonen at maanmittauslaitos.fi>> wrote:
Hi,

WCS users are supposed to read the metadata with DescribeCoverage, for example https://avoin-visukuva.nls.fi/ortokuvat-ja-korkeusmallit/wcs/v1?service=WCS&version=2.0.1&request=DescribeCoverage&coverageID=ortokuva_vari
The units can be configured in the mapfile with “wcs_band_uom”. I do not know if it is possible to configure the outputformat to write uom also into the TIFF. That is something that GDAL should do.

-Jukka Rahkonen-



Lähettäjä: MapServer-users <mapserver-users-bounces at lists.osgeo.org<mailto:mapserver-users-bounces at lists.osgeo.org>> Puolesta Carl Godkin
Lähetetty: keskiviikko 12. tammikuuta 2022 3.58
Vastaanottaja: Mapserver-Users (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>>
Aihe: [mapserver-users] WCS layer units question...

Hi,

I have a local WCS & WMS server.

I am trying to figure out if I can somehow define the Z units of a terrain layer I'm serving.

The single band from the individual GeoTIFF files providing the terrain data looks like this (from gdalinfo):

Band 1 Block=512x512 Type=Float32, ColorInterp=Gray
  Description = Layer_1
  NoData Value=-999999
  Unit Type: m     <===================================== units are meters
  Metadata:
    LAYER_TYPE=athematic
    RepresentationType=ATHEMATIC

but when I download a GeoTIFF using a WCS GetCoverage request on this layer, the GeoTIFF's single band just looks like this:

Band 1 Block=571x3 Type=Float32, ColorInterp=Gray

without "Unit Type."

I also tried using
   UNITS Meters
in my LAYER definition in my map file (copying an example I found among the case studies on the web site) but it didn't seem to have any effect.

Is there some way to define and retrieve the Z units for a WCS server?

Thanks very much.

carl
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