[gdal-dev] Retrieving 3DEP data via GDAL's WCS driver...

[Carl Godkin]

Hi Tanya,

Thanks for the suggestion.  I wondered about that too but there's only one
endpoint for "3DEP" in that WCS link so I don't know how to switch
products with WCS.  It appears from this view

https://viewer.nationalmap.gov/basic/?basemap=b1&category=ned&q=&zoom=9&bbox=-107.61108398,36.81368259,-105.38909912,38.17775097&preview=&avail=DEM
1/9 arc-second&refpoly=

that I might be near the edge of the 1/9 arc second availability but I
would have thought that the service would fill in from the next higher
resolution but I can find little in the way of documentation of this
assumption.  I have also written to the The National Map help email and I'm
hoping that someone either here or there can set me straight.

Thank you so much for the response,
carl

On Sat, Jun 13, 2020 at 6:20 PM TC Haddad <tchaddad at gmail.com> wrote:

>
> Hi Carl,
>
> Is it possible that you are just encountering the edges of the subdataset?
>
> That URL you provided in your first email had the list of indexes for the
> collection of data sets, maybe you can cross reference the shapes it was
> showing with the edges you are getting, to see if you need to switch to a
> different product when you are in certain areas:
>
>
> http://www.arcgis.com/home/webmap/viewer.html?url=https%3A%2F%2Findex.nationalmap.gov%2Farcgis%2Frest%2Fservices%2F3DEPElevationIndex%2FMapServer&source=sd
>
> Tanya
>
> On Sat, Jun 13, 2020 at 5:28 PM Carl Godkin <cgodkin at gmail.com> wrote:
>
>> Hi,
>>
>> This page https://viewer.nationalmap.gov/services/ includes a link under
>> "WCS Services" that lists a number of subdatasets.  This command
>>
>> gdalnfo "
>> https://elevation.nationalmap.gov/arcgis/services/3DEPElevation/ImageServer/WCSServer?request=GetCapabilities&service=WCS
>> "
>>
>> works fine.  I have been retrieving elevation data from the first
>> subdataset:
>>
>>   SUBDATASET_1_NAME=WCS:
>> https://elevation.nationalmap.gov:443/arcgis/services/3DEPElevation/ImageServer/WCSServer?version=2.0.1&coverage=DEP3Elevation
>>   SUBDATASET_1_DESC=DEP3Elevation
>>
>> and most of the time it works but I think I must be doing something wrong
>> since sometimes there are large missing areas.
>>
>> For instance this area (Boston) works just fine:
>>
>> gdal_translate "WCS:
>> https://elevation.nationalmap.gov:443/arcgis/services/3DEPElevation/ImageServer/WCSServer?version=2.0.1&coverage=DEP3Elevation"
>> test.tif -projwin -71.07 42.36 -71.03 42.33 -projwin_srs EPSG:4326 -tr 100
>> 100
>>
>> but this command with only a different "projwin" (in Colorado) is about
>> 75% missing:
>>
>> gdal_translate "WCS:
>> https://elevation.nationalmap.gov:443/arcgis/services/3DEPElevation/ImageServer/WCSServer?version=2.0.1&coverage=DEP3Elevation"
>> test.tif -projwin -107.03 37.28 -107 37.25 -projwin_srs EPSG:4326 -tr 100
>> 100
>>
>> Can anyone help me understand what I'm doing wrong here and how to fix
>> it?
>>
>> I am using a very recent OSGeo4W featuring GDAL 3.0.4, released
>> 2020/01/28.
>>
>> Thanks very much for your help,
>>
>> carl
>> _______________________________________________
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>
>
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