[SoC] Distance Analysis for PostGIS Raster - Report Week 2 (Qing Liu)

[Pierre Racine]

Qing,

I would like you to present yourself and your project on postgis-devel. More people will certainly have something to say.

I really think we want to avoid having to produce an intermediate raster of sources. PostGIS is strong on raster/vector interaction and I really don't see why someone would prefer to provide sources as raster. The sources should come from a table of point. Now this raise a certain number of issues:

  -What if the table contains more than one point?
  -What if some of those points are outside the raster extent?
  -Another issue is: What if the raster I want to produce does not fit into the PostgreSQL maximum field size?

These are the kind or difficulties one encounters when working in a database.

Think about large tiled coverage, Delaunay triangulation,  aggregate functions and all the combinatory of "small/very large number of point" and "small/very large raster coverage". Ideally we want to provide a solution working for every limit cases.

Good reports BTW.

Pierre

> -----Original Message-----
> From: Qing Liu [mailto:liu.qing.1984 at gmail.com]
> Sent: Friday, June 01, 2012 9:02 PM
> To: soc at lists.osgeo.org
> Cc: Pierre Racine
> Subject: Distance Analysis for PostGIS Raster - Report Week 2 (Qing Liu)
> 
> Hi All,
> 
> Due to final exams week, I didn't work too much on my project this week.
> However, I read a lot documents and articles to get a better understanding of
> PostGIS Raster and raster data storage in spatial database. I will have to speed it
> up from next week.
> 
> You can find my Second weekly report here:
> http://trac.osgeo.org/postgis/wiki/PostGIS_Raster_SoC_Idea_2012/Distance_A
> nalysis_Tools#Week2Report
> 
> Have a nice weekend!
> 
> Qing