[Qgis-user] QGIS MBTiles

[Stefan Löhr]

Hi,

thanks for your fast answer.

I opened the dataset with "spatialite-gui.exe" and it seems to be 
populated with a lot of tiles.
The minzoom and maxzoom entries in "metadata" are also present:
##########################
name    value
format    png
version    1.0.0
center    16.500071,63.322846,4
name    doete
tags    asdf
bounds    -20.999853,37.645693,53.999995,89.000000
legend    [....]
credits    asdf
maxzoom    19
type    overlay
attribution
minzoom    0
description    ad
use_constraints    asdf
##########################

The coordinates seem to be somewhat strange, but the rest looks ok.
The strange thing is:
It says maxzoom=19, but in the "tiles" table, there are only tiles up to 
zoom-level 17.
Could that be the problem?

Stefan



Am 23.11.2016 um 13:55 schrieb Even Rouault:
>
> Stefan
>
> >
>
> > when I try to add a raster layer based on a local MBTiles file in QGis
>
> > 2.14 I get this error:
>
> > "Nicht unterstütztes Datenformat: D:\Files\Testdata.mbtiles ist keine
>
> > unterstützte Rasterdatenquelle Cannot find min and max tile numbers"
>
> >
>
> > Did someone successfully use MBTiles with QGis?
>
> Yes sure.
>
> This error messages comes from the underlying GDAL MBTiles driver. 
> There is something in your dataset that it doesn't like. Either the 
> driver isn't robust to this case, either the mbtiles isn't conformant. 
> But hard to tell without access to the file.
>
> >
>
> > Where is QGIS searching for the "min and max tile numbers"? Does it have
>
> > to be in one of the metadata tables?
>
> > Or is it somehow calcluated on the fly?
>
> It looks at the metadata table for 'minzoom' and 'maxzoom' entries. If 
> not found, it then looks at the tiles table to query the min and max 
> values of zoom_level.
>
> The error could occur if the MBTiles dataset is completely empty. 
> Otherwise I'm not sure without inspecting it.
>
> Even
>
> -- 
>
> Spatialys - Geospatial professional services
>
> http://www.spatialys.com
>

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