<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Oct 19, 2021 at 5:37 PM Rahkonen Jukka (MML) <<a href="mailto:jukka.rahkonen@maanmittauslaitos.fi">jukka.rahkonen@maanmittauslaitos.fi</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p class="MsoNormal"><span>Hi,<u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Here is more accurate documentation but only in the text
<a href="https://www.mapserver.org/ogc/wcs_server.html" target="_blank">https://www.mapserver.org/ogc/wcs_server.html</a><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">“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.” <u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">It seems that only wcs_extent is documented in the list of metadata elements but this is what they do:<u></u><u></u></span></p>
<ul style="margin-top:0cm" type="disc">
<li class="gmail-m_-2742205112121419395MsoListParagraph" style="margin-left:0cm"><span lang="EN-US">wcs_extent defines the bounding box or your coverage -> that will go into DescribeCoverage<u></u><u></u></span></li><li class="gmail-m_-2742205112121419395MsoListParagraph" style="margin-left:0cm"><span lang="EN-US">wcs_size is the size of the coverage as pixels -> pixel size can be computed by extent and size<u></u><u></u></span></li><li class="gmail-m_-2742205112121419395MsoListParagraph" style="margin-left:0cm"><span lang="EN-US">wcs_resolution tells the pixel size explicitly -> size of the coverage in pixels can be computed</span></li></ul></div></div></blockquote><div>Thanks a lot, Jukka. That all makes some sense as far as it goes, but I'm still not clear on a few details. I have this range of data: 24N to 50N and 125W to 66W which is 26 degrees by 59 degrees.</div><div><div><br></div><div>Since the SRTM data has 3 arc-second spacing, that's 1200 pixels per degree plus one for the extra edge so I have tried a number of things without success.</div></div><div><br></div><div>1. Is wcs_size the size FULL range of the tiles that I have? And what is the order? </div><div>2. Again, what is the order for wcs_resolution? Are the units degrees since the coordinate system of the original data is EPSG:4326?</div><div><br></div><div>I've tried all of these, one at a time, and get various errors. (1 / 1200 = 0.00083333...)</div><div><br></div><div><div style="color:rgb(0,0,0);font-size:14px;line-height:19px;white-space:pre"><div style="font-family:Consolas,"Courier New",monospace"> <span style="color:rgb(0,128,0)">#"wcs_resolution" "0.00083333 0.00083333"</span></div><div style="font-family:Consolas,"Courier New",monospace"> <span style="color:rgb(0,128,0)">#"wcs_size" "70801 31201"</span></div><div style="font-family:Consolas,"Courier New",monospace"> "wcs_size" "31201 70801"</div><div style="font-family:Consolas,"Courier New",monospace"><br></div><div style=""><font face="arial, sans-serif">In case it's helpful, here's my LAYER definition (with probably extra things I've tried based on my searching and trial & error):</font></div><div style=""><br></div><div style=""><div style="font-family:Consolas,"Courier New",monospace;line-height:19px"><div> <span style="color:rgb(121,94,38)">LAYER</span></div><div> <span style="color:rgb(0,0,255)">NAME</span> SRTM_<span style="color:rgb(9,134,88)">3</span>_arc-second_grid</div><div> <span style="color:rgb(121,94,38)">METADATA</span></div><div> "<span style="color:rgb(163,21,21)">wcs_label</span>" "SRTM - 3 arc-second grid" <span style="color:rgb(0,128,0)">### required</span></div><div> "<span style="color:rgb(163,21,21)">wcs_rangeset_name</span>" "Range 1" <span style="color:rgb(0,128,0)">### required to support DescribeCoverage request</span></div><div> "<span style="color:rgb(163,21,21)">wcs_rangeset_label</span>" "Lower 48" <span style="color:rgb(0,128,0)">### required to support DescribeCoverage request</span></div><div> "ows_extent" "-125 24 -66 50"</div><div> <span style="color:rgb(0,128,0)">#"wcs_resolution" "0.00083333 0.00083333" # 1/1200 for 3" spacing?</span></div><div> <span style="color:rgb(0,128,0)">#"wcs_size" "70801 31201" # Not sure of order</span></div><div> "wcs_size" "31201 70801"</div><div> "wcs_bandcount" "1"</div><div> "<span style="color:rgb(163,21,21)">wcs_native_format</span>" "SRTMHGT" # What should this be? I can't find examples...</div><div> "<span style="color:rgb(163,21,21)">wcs_srs</span>" "EPSG:4326"</div><div> <span style="color:rgb(121,94,38)">END</span></div><br><div> <span style="color:rgb(0,0,255)">TYPE</span> <span style="color:rgb(0,16,128)">RASTER</span> <span style="color:rgb(0,128,0)">### required</span></div><div> <span style="color:rgb(0,0,255)">STATUS</span> <span style="color:rgb(0,16,128)">ON</span></div><div> <span style="color:rgb(0,0,255)">TILEINDEX</span> "../srtm_3_hgt/srtm_3_hgt-index.shp" <span style="color:rgb(0,128,0)"># Path is relative to SHAPEPATH</span></div><div> <span style="color:rgb(0,0,255)">TILEITEM</span> "Location"</div><div> <span style="color:rgb(121,94,38)">PROJECTION</span></div><div> "init=epsg:4326"</div><div> <span style="color:rgb(121,94,38)">END</span></div><div> <span style="color:rgb(121,94,38)">END</span></div></div>
I feel like I must be close. Thanks a lot for any further pointers,</div><div style=""><br></div><div style="">carl</div></div></div><div><br></div></div></div>