[gdal-dev] gdalbuildvrt & gdal2tiles.py with GeoTIFF across anti-meridian...

[Petr Pridal]

Hi Jan,

It is worth mentioning that if you render map tiles (mercator or different)
for large area from multiple input files and you are hitting issues like:

- heterogenous projections (differing srs in input files)
- alpha compositing of input files
- dateline crossing  (anti-meridian) issues
- speed issues (parallelisation on multiple CPUs)
- size of the produced PNG tiles
- tiles output in XYZ / TMS and in non-mercator grids with WMTS
compatibility
- direct MBTiles / SQLite output

you can try the MapTiler Pro command-line interface, as it solves all
mentioned problems directly. Just pass your input files directly on the
command line - without creating any VRTs in advance. MapTiler is software
powered by GDAL and used in production by many.
You can get the software as .rpm and .deb for various linux distros, use it
via Docker container as well as with native installers for Mac OS X and
Windows on your laptop - just fill the form: http://www.maptiler.com/demo/.

Disclaimer: I am the original author of GDAL2Tiles and member of the
KlokanTech.com team, who works on the MapTiler software, which is a
commercial product.

We work on the software for years now, and thanks to our customers we are
also able to support open-source GDAL as well (for example with the
significantly improved GeoPDF rendering driver powered by PDFium which is
going to be part of GDAL 2.1 - thanks to Evan's review).

In case you have extremely large dataset to render, you can also join
testers of the cluster variant of MapTiler, which is able to split the tile
rendering to tasks executed on multiple computers.
This is now being developed as part of research project done in cooperation
with Google Inc. as a partner. Google Cloud platform as well as Amazon EC2
or internal clusters or private clouds are going to be supported.

Best regards,

Petr


On Tue, Jan 5, 2016 at 4:20 PM, Jan Knepper <jan at knepper.net> wrote:

> All,
>
> Running across (an) other issue(s)...
>
> I was able to gdalwarp a .tif overlapping the anti-meridian with --config
> CENTER_LONG 180
>
> Next step was to use gdalbuildvrt to build a .vrt file in preparation for
> tiling with gdal2tiles.py.
> When trying that this message displays:
> Warning 6: gdalbuildvrt does not support heterogenous projection. Skipping
> ...
> And the skipped file is not included in the .vrt file.
>
> I tried using the --config CENTER_LONG 180 with gdalbuildvrt which gives
> the same result.
>
> Then I tried:
> gdalbuildvrt --config CENTER_LONG 180 -allow_projection_difference ...
>
> This does NOT give the previous message, but after running gdal2tiles.py
> on the .vrt the tiles that should have been generated from the .tif file in
> question appear to be missing...
> Any thing specific I should do to make this work?
>
> Something else I noticed is that it seems to be important in what order
> .tif files are submitted to gdalbuildvrt. Many if not all the .tif(s) used
> have an Alpha Channel for transparency because they are 'cut' from a .tif.
> What I see happening is that the transparent part of a *later* .tif wipes
> the non-transparent parts of *earlier* .tif(s) it overlaps. Is there an
> easy solution for this?
>
> GDAL 1.11.2, released 2015/02/10
>
> Any help/assistance would be appreciated!
>
> Thanks!
> Jan
>
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>



-- 
Petr Pridal, Ph.D.
CEO

Klokan Technologies GmbH
Hofnerstrasse 98, 6314 Unterageri, Switzerland
Tel: +41 (0)41 511 26 12
Email: info at klokantech.com
Web: http://www.klokantech.com/
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