[Qgis-user] QField
Neumann, Andreas
a.neumann at carto.net
Thu Sep 22 01:06:33 PDT 2016
Hi Matthias,
Oh - thanks for the hint. So probably Reginald is just missing the
pyramids in the geopackage - to be created, f.e. with gdaladdo.
Andreas
On 2016-09-22 09:56, Matthias Kuhn wrote:
> QField does not (yet) support tiff with jpeg compression.
>
> See:
> http://www.qfield.org/docs/project-management/dataformat.html#raster-data
>
> GeoPackage worked quite nice in our experience and can also be built in different resolutions (same page further down).
>
> Matthias
>
> On 09/22/2016 09:37 AM, Neumann, Andreas wrote: Hi Reginald,
>
> You can use the JPEG compression inside Geotiff. Note that this can be
> specified separately for both the full resolution and the pyramids. You
> can also select the compression factor to decrease the file size in
> trade off with quality.
>
> See
> also http://www.gdal.org/frmt_gtiff.html and http://www.gdal.org/gdaladdo.html for
> details.
>
> I believe that modern QGIS versions have these options exposed in the
> GUI, but probably not as default.
>
> So maybe there is room for potential to get a smaller size Geotiff.
>
> Greetings,
> Andreas
>
> On 2016-09-22 09:32, Reginald Carlier wrote:
>
> Thanks Andreas,
>
> Creating a Geotiff with pyramids did the trick. The only disadvantage
> is that it created a file of about 1.7 GB (the original was 90 MB).
>
> Now I am ready to test the app J.
>
> Regards,
>
> *Van:*Neumann, Andreas [mailto:a.neumann at carto.net]
> *Verzonden:* woensdag 21 september 2016 16:19
> *Aan:* Reginald Carlier
> *Onderwerp:* Re: [Qgis-user] QField
>
> Hi Reginald,
>
> Did you create pyramids in the gpkg rasters?
>
> Generally, Geotiff should be well supported - definitely more tested
> than gpkg rasters. I had a 1GB geotiff on qfield (on SD-Card) and it
> displays fast. I haven't tested vrt files with geotiffs - if it works
> as well?
>
> Andreas
>
> On 2016-09-21 15:44, Reginald Carlier wrote:
>
> Hi Erwan,
>
> You can look in the list of last week where I posted a couple of
> questions about qfield and was pointed to the right website for
> documentation.
>
> I succeeded to publish a map on my phone but the aereal photo
> which was published as a gpkg file doesn't render. When I use the
> raster.gpkg on my desktop it renders but very slow.
>
> The gpkg file was created from a 90 MB jp2 file.
>
> Regards,
>
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