[gdal-dev] MBTiles minimum zoom level definition

Previous Topic Next Topic
 
classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

[gdal-dev] MBTiles minimum zoom level definition

Bernardo Fabiani

Hi, list

I’m using gdal_translate and gdaladdo to generate MBTiles following the documentation here.

By reading previous threads, 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 and inserting the levels option, I was not able to go past a certain ‘out zoom level’. Also in here, 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?


_______________________________________________
gdal-dev mailing list
[hidden email]
https://lists.osgeo.org/mailman/listinfo/gdal-dev
Reply | Threaded
Open this post in threaded view
|  
Report Content as Inappropriate

Re: MBTiles minimum zoom level definition

Even Rouault-2

Bernardo,

 

>

> 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

 

Even

 

--

Spatialys - Geospatial professional services

http://www.spatialys.com


_______________________________________________
gdal-dev mailing list
[hidden email]
https://lists.osgeo.org/mailman/listinfo/gdal-dev
Loading...