[gdal-dev] MBTiles minimum zoom level definition
even.rouault at spatialys.com
Sun Apr 16 11:30:00 PDT 2017
> I’m using gdal_translate and gdaladdo to generate MBTiles following the
> documentation here <http://www.gdal.org/frmt_mbtiles.html>.
> By reading previous threads
> <https://lists.osgeo.org/pipermail/gdal-dev/2016-April/044130.html>, I’ve
> understood that gdal_translate determines the baseview zoom level based on
> the original image resolution - if I’d like a higher level of zoom, I need
> to upsample. That enabled the control of the *maximum* zoom level.
> However, I when using gdaladdo <http://www.gdal.org/gdaladdo.html> and
> inserting the levels option, I was not able to go past a certain ‘out zoom
> level’. Also in here <http://www.gdal.org/frmt_mbtiles.html>, it is
> explicitly mentioned that
> If more overview levels are specified than available, the extra ones are
> silently ignored.
> *My question is*: how can I (directly or indirectly) specify the *minimum*
> zoom level for a given image in MBTiles generation using gdal_translate?
Well as you saw, when using gdal_translate you implicitely define the maximum zoom level.
So look at the gdalinfo report on it, and it will mention this zoom level. Let's say N.
If you do "gdaladdo my.mbtiles 2 4 8 16", this will compute levels N-1, N-2, N-3, N-4.
This works until the dimension of the overview is below 128x128 if I remember well
Spatialys - Geospatial professional services
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