[Freegis-list] Ideas on best FOSS options
jcz at northredoubt.com
Wed Feb 6 05:10:55 CET 2008
Artem Pavlenko wrote:
> On 4 Feb 2008, at 02:01, John Zastrow wrote:
>> I need to create an attractive set of static tiles for the USA (based on
>> shapefiles) to populate a web-server-only (e.g., small-footprint, not
>> dynamic, not a real map server) online map to embed in a java-based
>> application without internet access.
>> My first attempt used ArcGIS to render a GeoTIFF of a layout at high
>> resolution and then passed the image into gdal2tiles.py
>> (http://www.klokan.cz/projects/gdal2tiles/) (which is EXCELLENT) to
>> create a shell OpenLayers app that I can customize. This worked fine,
>> except the image quality from ArcGIS was horrible, particularly when
>> zoomed in (no anti-alias).
> I don't think your approach will work. Even if you manage to create a
> very large geotiff, re-sampling it to create low resolution tiles
> would produced anything but nice looking maps. Also, for high zoom
> levels the image size will blow your memory away. Creating good
> cartography would most certainly require per zoom level styling.
>> I'm a now trying to use mapnik (mapnik.org) to create the same image at
>> higher quality. But I am suffering deeply from an acute lack of
>> documentation which makes creating the cartography even more painful
>> (where are recipes, examples, and docs for mapnik?)
> Have a look at :
> This script generates tiles with all styles and data defined in :
>> Is there something else that I can use to create the tiles needed for
>> the OpenLayers app?
> I suggest you read OpenLayers docs.
>> Or is there an easier tool for creating a high-res,
>> high-quality georeferenced image that can be used by gdal2tiles.py? Any
>> thoughts would be greatly appreciated.
> I'm not familiar with gdal2tiles.py but as I mentioned above,
> re-sampling vector maps won't produce high-res, high-quality tiles
> (assuming this is what you're trying to achieve). You might try
> creating two layers : chop your raster data with gdal2tiles.py and
> create transparent overlay tiles using Mapnik. Also, Mapnik supports
> gdal raster directly and you can generate high quality tiles with
> raster and vector combined. see 
Ok, you lost me a little with your last note (I agree, I'd like to weave
together at least two zoom levels into a static tile set). Are you
saying that Mapnik can import the newly cut tiles and set transparency
(perhaps based on a color)? Can you elaborate on what I would do with
Mapnik's support for GDAL rasters? If  was a link it did not come
through in the email.
More information about the Freegis-list