SoC 2008 - GDAL2Tiles Improvements

GDAL2Tiles creates a lighten and easy to use alternative to combination of WMS + TileCache (or ​GeoWebCache based on last year SoC jTileCache.

It allows simple conversion of existing raster maps into directory structure of tiles, which after uploading on a webserver act as a map source for online viewers. A client viewer (typically a web application) is using the same protocol as when querying dynamically generated tiles from TileCache server (protocol TMS).

This Summer of Code project will improve existing GDAL2Tiles utility done in the last year.

Main part of work is in implementation of global profiles in TMS, improvement of the quality of the render of tiles, and rewriting of HTML templates for standard viewers (based on OpenLayers, Google Maps, MS Virtual Earth, ...). All the changes will be commited to the code of GDAL2Tiles, as well as existing pending patches #2052 - (JPEG and TIFF tiles support) and #2053 (world files for tiles). This way the GDAL2Tiles utility will be ready (feature complete) for rewrite into a R/W Driver, which is done in separate SoC Project GDAL TMS Driver

Support for tiles compatible with Google Maps/MSN Virtual Earth/Yahoo Maps/…

Right now the GDAL2Tiles utility doesn't support global-profiles from standard TMS. It means static tiles are not overlayable with Google Maps. This is going to change. Support for both global-mercator (based on Google Projection EPSG:900913) and global-geodetic (based on EPSG:4326) will be implemented. Those two

GDAL2Tiles will generate tiles from supplied raster file (GeoTIFF, MrSID, ECW, ... ) with proper georeference headers. Result structure (e.g. directory with tiles, MapResource.xml containing all necessary geo-metadata and optionally an simple HTML viewerers (based on OpenLayers, Google Maps, ...), as well as KML for Google Earth SuperOverlay) can be simply published on any webserver.

Produced tiles can be used as overlay map on top of Google Map tiles or other available map sources. The simple client will allow ​presentation with overlay like this one.

OpenLayers 100% TMS support

Improvement of TMS viewer in OpenLayers.org. Patch with improvement for TMS driver would be submitted into the project OpenLayers. - Implementing parser for MapResource.xml, better support for tiles in local

New suggestions for TMS Standard

​Definition of the TMS Standard will be extended for pictures, restructured, extended with several suggestions, after discussion with community. Hopefully we will specify a new back compatible version with small changes (like replacement of ​OSGEO:41001 with EPSG:900913, extension of MapResource.xml, etc.). Such standard will be discussed and compared with OGS WMS-C.

Possible features

• Cooperation on HTTP Read driver for TMS tiles in GDAL, which will allow warping of remotely published TMS tiles, and hopefully also allow MapServer act as a WMS proxy for tiles published as static files on a webserver.

• Utility Tiles2Tiles which will convert (mostly by simple rename) tiles beetween TMS and other formats, like MSR MapCruncher, WorldWind, GeoQuadTree, Zoomify, etc.

Student info

My name is Klokan Petr Přidal, I am a postgraduate student of Cartography at Czech Technical University in Prague. Contact is on ​my website and info about my work on ​LinkedIN profile.