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<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">No, I am not sure because I do not program myself. Reading this document
<a href="https://gdal.org/user/multithreading.html">https://gdal.org/user/multithreading.html</a> makes me feel that it is possible to do some things in parallel, but the programmer must know how to do it right.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">-Jukka Rahkonen-<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">Lähettäjä:</span></b><span lang="EN-US"> Javier Jimenez Shaw <j1@jimenezshaw.com>
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<b>Lähetetty:</b> keskiviikko 29. toukokuuta 2024 10.41<br>
<b>Vastaanottaja:</b> Rahkonen Jukka <jukka.rahkonen@maanmittauslaitos.fi><br>
<b>Kopio:</b> Micha³ Kowalczuk <michkowalczuk@gmail.com>; gdal-dev@lists.osgeo.org<br>
<b>Aihe:</b> Re: [gdal-dev] GDAL WMTS get tiles no documentation<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">On Wed, 29 May 2024 at 08:59, Rahkonen Jukka via gdal-dev <</span><a href="mailto:gdal-dev@lists.osgeo.org"><span lang="EN-US">gdal-dev@lists.osgeo.org</span></a><span lang="EN-US">> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">When you have a RasterBand from the WMTS data source, it is abstracted and you can read the raster data just like from any other data source and raster band
</span><a href="https://gdal.org/tutorials/raster_api_tut.html#reading-raster-data" target="_blank"><span lang="EN-US">https://gdal.org/tutorials/raster_api_tut.html#reading-raster-data</span></a><span lang="EN-US"> “There are a few ways to read raster data,
but the most common is via the GDALRasterBand::RasterIO() method. This method will automatically take care of data type conversion, up/down sampling and windowing.” GDAL knows which tiles to read.<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">I do not know if the WMTS driver can do parallel tile downloads. If not, it is possible to run many RasterIO() at the same time, each reading data from a different
window like in this rasterio document </span><a href="https://rasterio.readthedocs.io/en/latest/topics/concurrency.html" target="_blank"><span lang="EN-US">https://rasterio.readthedocs.io/en/latest/topics/concurrency.html</span></a><span lang="EN-US">.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Jukka, are you sure you can run several RasterIO in parallel (on the same dataset)? in GDAL GeoTIFF you cannot: the cache may be corrupted. In that case I open several datasets over the same file. I do not know about
WMTS.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">-Jukka Rahkonen-<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span lang="EN-US">Lähettäjä:</span></b><span lang="EN-US"> gdal-dev <</span><a href="mailto:gdal-dev-bounces@lists.osgeo.org" target="_blank"><span lang="EN-US">gdal-dev-bounces@lists.osgeo.org</span></a><span lang="EN-US">>
<b>Puolesta </b>Michal Kowalczuk via gdal-dev<br>
<b>Lähetetty:</b> keskiviikko 29. toukokuuta 2024 9.08<br>
<b>Vastaanottaja:</b> </span><a href="mailto:gdal-dev@lists.osgeo.org" target="_blank"><span lang="EN-US">gdal-dev@lists.osgeo.org</span></a><span lang="EN-US"><br>
<b>Aihe:</b> [gdal-dev] GDAL WMTS get tiles no documentation<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Hi GDAL fellows<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">This is my first post on this mailing list, so I'm asking for understanding.<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">As all we know the purpose of using WMTS over WMS, I'd like to implement parallel downloading tiles from service using C API.<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">In my opinion GDAL documentation (</span><a href="https://gdal.org/drivers/raster/wmts.html" target="_blank"><span lang="EN-US">https://gdal.org/drivers/raster/wmts.html</span></a><span lang="EN-US">)
says nothing on this topic.<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">I can get capabilities from WMTS, I can open the selected subdataset but how to get tiles for given extent? I could not find any information how to do it, even
in the GDAL tests on github.<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">I am kindly asking for tips. It also can be in python. How using pure GDAL API fetch tiles to dynamically complete the displayed map. This is my goal.<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Thank you!<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Michal<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">_______________________________________________<br>
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