Difference between revisions of "Main Page/Research/MSB/vertex-level tracking"

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#: <tt>''' copy (select asewkt(line_waspn) from s56_coords) to '/tmp/coords.txt';'''</tt>
 
#: <tt>''' copy (select asewkt(line_waspn) from s56_coords) to '/tmp/coords.txt';'''</tt>
 
# Read into R
 
# Read into R
 +
## Use the <tt>stediff </tt> command to find numbers of points that were deleted.

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.