Revision as of 18:08, 24 March 2009

Vertex-level tracking of edits from MSB data

• GIS typically does not store vertex-level attributes.
• The XYZ coordinates in 2.5D line data sets may be used for uniquely identifying vertices

1. Download data from UBI (Jonathan's server space)
2. Perform pre-processing
   1. Includes concatenation of bouts
3. Uniquely identify records

   dat$id <- seq(1, nrow(dat)) (R)

4. Generate lines (using sub-bout parser)
   1. Write out PostGIS code for importing XYZ line data

      Relies on the LINESTRING geometry with 3 dimensions

   2. Create VIEWs for stationary vs moving lines
   3. Dump from PostGIS using pgsql2shp

      Maintains XYZM coordinates on vertices

5. Edit in ArcMap (Use 3rd-party vertex mass editor [ET Tools from ian-ko.com])

   Deleting individual vertices drops them and does not re-order, i.e., maintains the Z coordinate on each XY vertex. (My tests of ArcView 3 showed failure in this regard).

6. Import shapefile as PostGIS table

   Maintains XYZ coordinates

7. Dump from PostGIS; this example shows how to dump each record as an EWKT format (XYZ text)

   copy (select asewkt(line_waspn) from s56_coords) to '/tmp/coords.txt';

8. Read into R
   1. Use the stediff command to find numbers of points that were deleted.