Changes between Version 20 and Version 21 of PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools

Timestamp:

Jun 17, 2012, 3:34:34 PM (12 years ago)

Author:

qliu

Comment:

—

PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools

@@ -46 +46 @@
 <LI><A href=http://trac.osgeo.org/postgis/wiki/PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools#Week2Report>Week 2 Report (May 28th - June 1st)</A></LI>
 <LI><A href=http://trac.osgeo.org/postgis/wiki/PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools#Week3Report>Week 3 Report (June 4th - June 8th)</A></LI>
+<LI><A href=http://trac.osgeo.org/postgis/wiki/PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools#Week4Report>Week 4 Report (June 11th - June 15th)</A></LI>
 </UL>
 <br>
@@ -101 +102 @@
  * It seems that Oracle Sptial dosenot provide distance analysis [http://docs.oracle.com/cd/B28359_01/appdev.111/b28398/geor_operations.htm#CIHIICDF functions for GeoRaster] data. '''Please let me know if I missed it.'''[[BR]]However, by reading documents of !GeoRaster, I got a better understanding of the raster data storage in spatial database. So I feel it would be helpful for me to write an analysis to compare the concepts of raster data storage and manipulation with PostGIS Raster and Oracle Spatial !GeoRaster.
 
+#!html
+<div style='background-color: #F4F4F4; border: 1px solid gray; width:400px;' >
+<br>
+<b>Comment from Mentor:</b>
+<p>
+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.
+</p>
+<br>
+</div>
+}}}
+
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