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<p>Hi,</p>
<p>There is a gis stackexchange question open regarding this which
has some good inputs to consider.</p>
<p><a class="moz-txt-link-freetext" href="https://gis.stackexchange.com/questions/309379/choosing-raster-format-for-qfield">https://gis.stackexchange.com/questions/309379/choosing-raster-format-for-qfield</a></p>
<p>There is also some information in the QField documentation
regarding this topic (although that could benefit from some
improvements from your findings, there's an edit on github link at
the bottom of the page ;) )</p>
<p><a class="moz-txt-link-freetext" href="https://www.qfield.org/docs/project-management/dataformat.html#raster-data">https://www.qfield.org/docs/project-management/dataformat.html#raster-data</a></p>
<p>Best regards</p>
<p>Matthias<br>
</p>
<div class="moz-cite-prefix">On 3/24/19 9:37 PM, Bernd Vogelgesang
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:ad625585-d408-b3e3-b843-a9957bcd9b66@gmx.de">Hi,
<br>
<br>
I need an aerial basemap for my QField-project to be able to
locate
<br>
positions. As QField has not the ability to navigate to a point or
<br>
indicate the direction of movement, provided only with a
topographic
<br>
basemap, I'm stumbling through the forest and have a hard time
finding
<br>
the positions.
<br>
<br>
The project area is huge, around 400 square kilometers! I have a
Mrsid
<br>
file of the area of 1.6 GB with 20 centimeter resolution,
<br>
transformed with gdal_translate to tiff is 42.5 GB,
<br>
compressed with gdal_transform with jped-compression 50% 968 MB,
<br>
resampled to 40cm resolution and 50% jpeg has 295 MB
<br>
<br>
I used the QField sync plugin to generate a baselayer in
gpgk-format
<br>
from this ,which has 540 MB with 40 cm resolution.
<br>
<br>
Unfortunately, on the tablet, the baselayer is loading so slow,
that it
<br>
is impossible to work with it. Each redraw takes around 10 seconds
in
<br>
the small scale, rising to infinity in higher scales.
<br>
<br>
I wonder if there are other approaches recommendable, for example
<br>
splitting the image into separate layers for bigger regions, which
I
<br>
could then turn on and off, or if I should prepare the image apart
from
<br>
using the plugins converter to gpkg.
<br>
<br>
Due to the enourmous amount of time needed to process the image on
the
<br>
PC, a trial-and-error approach seems not to be feasable, so I ask
you if
<br>
someone can recommend an approach for such a huge beast.
<br>
<br>
<br>
Thanx in advance,
<br>
<br>
Bernd
<br>
<br>
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<div class="moz-signature"> <span style="text-align: left;
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font-size: 10pt">Matthias Kuhn</span><br>
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