Changes between Initial Version and Version 1 of PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools

Timestamp:

May 31, 2012, 1:34:21 AM (12 years ago)

Author:

qliu

Comment:

—

PostGIS_Raster_SoC_Idea_2012/Distance_Analysis_Tools

@@ +1 @@
+= PostGIS Raster SoC Idea 2012 - Distance Analysis Tools for PostGIS Raster =
+
+'''Student:''' Qing Liu
+
+'''Idea''':
+The idea for this proposed project is to add two spatial analysis functions to PostGIS Raster that 
+implement two main ways of performing distance analysis: Euclidean distance calculation and 
+cost-weighted distance calculation. 
+
+Euclidean distance function will create a distance surface representing the Euclidean distance 
+from each cell in the source layer to the starting point or the closest source (as designated by user). 
+The basic concepts of the algorithm would be using the center of the source cell to calculate 
+the distance from it to the rest cells in the raster layer or within the user-defined extent.
+
+Cost-weighted distance will create a raster layer representing the accumulative cost distance 
+for each cell to the starting point or the closest source (as designated by user). A cost raster 
+layer will be generated using one or several factor layers representing the impedance of passing 
+through each cell according to user’s criteria. User can also put weights on the input factor layers 
+to represent different levels of importance for those factors. Factors such as: elevation, slope, 
+orientation, land use / land cover type; vehicle speed, accessibility; and a binary map layer could 
+also be used as a mask for defining geographic extent or as a filter for the output cost layer. 
+The accumulative cost values will be then assigned to each cell representing the cost per unit 
+distance for moving through this cell.
+
+'''GSoC 2012 Proposal: '''
+[[BR]]
+[http://google-melange.appspot.com/gsoc/proposal/review/google/gsoc2012/kya_na/1]
+
+
+== Week 1 Report ==
+
+'''What did you get done this week?'''
+ * Compiled PostGIS 2.0 sucessfully.
+ * Loaded raster data into PostgreSQL and practiced some query by finishing the raster/vector tutorial
+ * Write an analysis of how Euclidean distance and Cost-weighted distance are computed in ArcGIS and GRASS.
+ * Setup wiki page.
+
+''' What do you plan on doing next week?'''
+ * Learn more about PostGIS Raster concepts and functions
+ * Write an analysis of how Euclidean distance and Cost-weighted distance are computed in Oracle
+ * Start to write a proposal on how adopt the concepts and algorithms in PostGIS.
+
+'''Are you blocked on anything?'''
+ * As of now I was not blocked on anything yet, but working in a spatial database is something new and challenging to me. I will need to read and reserch more about it.
+ * However, it took me some time to understand how raster coverage is stored in PostGIS, and how Raster type works.
+
+
+'''Links of Analyses:'''
+ * How Euclidean distance and Cost-weighted distance are computed in ArcGIS and GRASS[[BR]][https://docs.google.com/document/d/1G6Ge3239kCBkn5qqpa1_0PNsvM9OWewsbI-2ZtSc3Cc/edit]