Here is the recommended workflow with GDAL2Tiles for Natural Earth and
similar world maps:
1. Download the source file from the Natural Earth website
http://www.shadedrelief.com/natural2/ data section.
2. Download also the World file and rename it the way that filename is
the same like the JPEG file and extension is .wld (i.e.
NE2_modis3.wld)
[optional step: conversion into .TIF because GDAL is quite slow on
huge JPEG files - it is better to use .tif instead of .jpg in the
workflow: gdal_translate NE2_modis3.jpg NE2_modis3.tif]
if you need KML files for Google Earth SuperOverlay and standalone web
presentation:
3. gdal2tiles.py --profile=raster --s_srs=epsg:4326 --force-kml
--url=http://web.address.com/ NE2_modis3.jpg
if you need KML files for Google Earth SuperOverlay and
web-presentation compatible with another WGS84 maps (from WMS for
example).
3. gdal2tiles.py --profile=geodetic --s_srs=epsg:4326 --force-kml
--url=http://web.address.com/ NE2_modis3.jpg
if you need Google Maps overlay web presentation:
3. gdalwarp -s_srs epsg:4326 -t_srs epsg:900913 -te -20037508.34
-20037508.34 20037508.34
20037508.34 -wo SOURCE_EXTRA=120 NE2_modis3.jpg NE2_modis3.tif
4. gdal2tiles --profile=mercator --s_srs=epsg:900913 --google-key=...
NE2_modis3.tif
I hope this tutorial will help more people...
A note:
Gdalwarp step for Google Maps presentation is reported as an issue in
MapTiler GUI and is related to gdal warping algorithm for the
world-maps into Mercator projection, all the details are here:
http://code.google.com/p/maptiler/issues/detail?id=6
Roberto: I tried exactly your workflow and I was not able to reproduce
your problems.
It would help if you upload your tiles and presentation with the
correct Google Maps API Key somewhere on the web and point me to that
location.
Klokan