[gdal-dev] WMTS gdal_translate vs RasterIO

[Rahkonen Jukka]

Hi,

I do not know either, I am not a programmer. I have used sometimes a local proxy server for capturing the http traffic. With gdal_translate the http requests are printed when the command is run with -- debug on. It would probably be good to run gdal_translate with -ovr NONE https://gdal.org/en/latest/programs/gdal_translate.html#cmdoption-gdal_translate-ovr and force it to use the full resolution image, because I quess that your code is also hitting the full resolution. Maybe gdal_translate is already hitting the same resolution, but by using -ovr it is you who makes the decision.

By reading the values it seems that you request 1073741760 pixels but for some reason GDAL believes that there are only 1073741756 pixels available. If I were a programmer, I think I would have a try with nXSize=1073741756.

May I ask why do you want to compress quite a large area of a raster into a single line of pixels? You have probably some interesting use case.

-Jukka Rahkonen-

Lähettäjä: Michał Kowalczuk <michkowalczuk at gmail.com>
Lähetetty: perjantai 30. elokuuta 2024 10.28
Vastaanottaja: Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi>
Kopio: Robert Coup <robert.coup at koordinates.com>; gdal-dev at lists.osgeo.org
Aihe: Re: [gdal-dev] WMTS gdal_translate vs RasterIO

Full GDAL log attached.
Sorry, but I do not know how to test your suggestion. GDAL logger creates some caches and I do not know which http request i should use...

Thanks, Michał

pt., 30 sie 2024 o 09:23 Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi<mailto:jukka.rahkonen at maanmittauslaitos.fi>> napisał(a):
Hi,

Capture and show the http request that your code generates and sends to the WMTS server. Does it work if you send the same request with curl or with a browser? Or does the error come before the GetTile request is generated?

-Jukka Rahkonen-

Lähettäjä: Michał Kowalczuk <michkowalczuk at gmail.com<mailto:michkowalczuk at gmail.com>>
Lähetetty: perjantai 30. elokuuta 2024 9.59
Vastaanottaja: Robert Coup <robert.coup at koordinates.com<mailto:robert.coup at koordinates.com>>
Kopio: gdal-dev at lists.osgeo.org<mailto:gdal-dev at lists.osgeo.org>; Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi<mailto:jukka.rahkonen at maanmittauslaitos.fi>>
Aihe: Re: [gdal-dev] WMTS gdal_translate vs RasterIO

Sorry for incorrect sample commands in the last message.
I fixed it. The problem stays the same, because the problem was in email not in my tested code.
gdal_translate -srcwin 0 0 1073741760 1553779 -outsize 691 1 "WMTS:https://basemap.nationalmap.gov/arcgis/rest/services/USGSHydroCached/MapServer/WMTS/1.0.0/WMTSCapabilities.xml,layer=USGSHydroCached,tilematrixset=default028mm" tile.png

GDALDatasetRasterIO(
handle_to_wmts_subdataset,
eRWFlag=GF_Read,
nXOff=0,
nYOff=0,
nXSize=1073741760,
nYSize=1553779,
pBuffer - buffer for data,
nBufXSize=691,
nBufYSize=1,
eBufType=GDT_Byte,
nBandCount=4,
panBandMap=[bIndex ,gIndex, rIndex, aIndex],
nPixelSpace=4,
nLineSpace=0,
nBandSpace=1)

Can anyone help me to understand why gdal_translate works and generates output file, where GDALRasterIO raises error:
Requested (0,0) of size 1073741760x1553779 on raster of 1073741756x1347126255?

czw., 29 sie 2024 o 12:22 Michał Kowalczuk <michkowalczuk at gmail.com<mailto:michkowalczuk at gmail.com>> napisał(a):
I see. I will double check commands, fix and return to this.

W dniu czw., 29.08.2024 o 12:20 Robert Coup <robert.coup at koordinates.com<mailto:robert.coup at koordinates.com>> napisał(a):
Hi Michał,

In addition to Jukka's key point:

  nBufXSize=1,
  nBufYSize=691,

appears to be backwards wrt:

  -outsize 691 1

Rob :)
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