Hi,

I was just about to suggest to use DEBUG. GDAL does not use 
“wcs_native_format”, it is used for setting what will be written into 
DescribeCoverage.

-Jukka Rahkonen-

Lähettäjä: Carl Godkin <cgod...@gmail.com>
Lähetetty: torstai 21. lokakuuta 2021 1.50
Vastaanottaja: Rahkonen Jukka (MML) <jukka.rahko...@maanmittauslaitos.fi>
Aihe: Re: [mapserver-users] WCS Tile index question

Sorry, right after I sent that last reply to the list, I thought of turning up 
the DEBUG value in the mapfile to 5 and now I see it's not finding my .hgt 
files for some reason.

I will dig into this; maybe mapserver + GDAL don't actually needs 
wcs_native_format.

More later to the list if I sort this out.  I really appreciate the help you 
and Jeff and others on the list have given me!

carl

On Tue, Oct 19, 2021 at 5:37 PM Rahkonen Jukka (MML) 
<jukka.rahko...@maanmittauslaitos.fi<mailto:jukka.rahko...@maanmittauslaitos.fi>>
 wrote:
Hi,

Here is more accurate documentation but only in the text 
https://www.mapserver.org/ogc/wcs_server.html

“The convention is that once (wcs|ows)_extent and one of (wcs|ows)_size and 
(wcs|ows)_resolution is set in the layer metadata, all the coverage specific 
metadata will be retrieved from there. Otherwise the source image is queried 
via GDAL, if possible.”

It seems that only wcs_extent is documented in the list of metadata elements 
but this is what they do:

  *   wcs_extent defines the bounding box or your coverage -> that will go into 
DescribeCoverage
  *   wcs_size is the size of the coverage as pixels -> pixel size can be 
computed by extent and size
  *   wcs_resolution tells the pixel size explicitly -> size of the coverage in 
pixels can be computed

We have in the LAYER-METADATA:
"wcs_resolution" "0.5 0.5"
"wcs_extent"          "19970 6597278 749676 7785300"

That should be enough and Describe Coverage will have correct limits, origin, 
and offset vectors in RectifiedGrid.

-Jukka Rahkonen-


Lähettäjä: MapServer-users 
<mapserver-users-boun...@lists.osgeo.org<mailto:mapserver-users-boun...@lists.osgeo.org>>
 Puolesta Carl Godkin
Lähetetty: keskiviikko 20. lokakuuta 2021 1.17
Vastaanottaja: 
mapserver-users@lists.osgeo.org<mailto:mapserver-users@lists.osgeo.org>
Aihe: [mapserver-users] WCS Tile index question

Hi again,

I am working with Mapserver trying to set up a WCS layer based on a large 
collection of SRTM .hgt files.

Since I have many input files instead of a single file, I want to use a tile 
index.  I know how to make and use a tile index for WMS, but there's a twist 
for WCS that I don't understand.

According to this section of the docs:
 
https://mapserver.org/optimization/tileindex.html?highlight=wcs_resolution#note-for-wcs-layers
<https://mapserver.org/optimization/tileindex.html?highlight=wcs_resolution#note-for-wcs-layers>

I need to set “wcs_extent”, “wcs_size”, and “wcs_resolution” but I don't see 
where they are defined or documented.

Can you point me to documentation?  The WCS Use Cases page gives some hints so 
I think I understand wcs_extent (though it's "ows_extent" in some examples 
there so I guess these are interchangeable?)

How are the others defined?

Thank you for your help,
carl


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