One of the things I'm most excited about in upcoming PostGIS 2.0
are the raster output
functions, largely created by Bborie Park. The latest one he added
ST_AsRaster
should be a welcome addition to even those who don't care about raster because it allows you to convert
regular PostGIS geometries to PostGIS raster and then use all the available export functions to output to your favorite
image format without ever leaving the database. If you want to try out PostGIS 2.0 and are on windows, you can download compiled versions for PostgreSQL 8.4-9.1
at: http://postgis.net/windows_downloads#PostGIS_2_0_0
This means that PostGIS is now both a spatial as well as a graphical database engine. To test out how I would
take advantage of these new features, I decided to create a mini ASP.NET 2.0+ app that is a PostGIS ad-hoc query viewer
for both PostGIS geometry and raster. We have it written in both VB.NET and C# and are planning to follow up very
soon with a PHP version. We'll also be putting up an online version and tutorial for people to play with who don't have PostGIS 2.0 installed so they can see what they are missing out on :).
You can also download the source code from:
http://www.postgis.us/downloads/postgis_webviewer_aspnet.zip
We'll be attending FOSS4G2011 in Denver this year, giving a tour of all the new treats in PostGIS 2.0 which will include this as well as PostGIS geometry analysis and maintenance functions/changes, 3D support types
and functions, Topology, and Tiger Geocoder. If you are attending, please attend our talk on
Friday PostGIS 2.0, the new stuff.
The Application Makeup
The application is very simplistic and is composed of 3 parts:
- JQuery for the html page UI which handles all the Ajax calls and DOM changes.
JQuery is pretty slick and the more I use it, the more I love it. If you do web development, you should
really give it a try.
- A stored function just so if I need to do more complex things like, intrusion detection,or benchmarking etc its compartmentalized.
- A server-side web handler that passes off the query to the stored function which returns back the query as a PNG file.
Check out these snapshots
I'm hoping in the very near term future to combine this with my favorite .NET reporting engine -- ActiveReports.NET which I currently use for my PostGIS based
web apps and which can take
database fields consisting of blobs of images. Being able to auto generate an image from spatial data to go in a report will be slick beyond imagination.
In the last article Minimalist Web based ASP.NET PostGIS 2.0 Spatial Geometry/Raster Viewer, we mentioned that we would provide a PHP equivalent. Well before we were able to lift our fingers, Bborie created a PHP version o the postgis handler and gave
Tracked: Aug 26, 18:13
A while back in New Additions and Promotions in PostGIS Development Team, I mentioned that the new addition to our team Bborie Park was working on image output functions for raster support, among other things. His last addition was ST_AsRaster which allo
Tracked: Aug 26, 18:50