[OSM-talk] Daily coastline shapefiles

Paul Norman penorman at mac.com
Mon Feb 6 19:03:49 GMT 2012


I have started daily coastline shapefile generation on my home server. The
data is pulled from my jxapi database and processed, starting at 1 AM PST (9
AM UTC) and takes 3-5 hours to generate and upload, depending on my internet
connection.

The files will be available at
http://pnorman.dev.openstreetmap.org/coastlines/ in about an hour.

The two shapefiles are coastline_p and processed_p. If there is demand I can
include the other files generated.

coastline_p is a shapefile with points indicating where the c programs found
geometry problems, typically where a section of coastline is missing.
Yesterday there were 25 of these. Not all of these impact rendering but some
result in flooding or dry oceans on the map. This can easily be opened in
software like qgis.

processed_p is a shapefile with areas broken into 100km by 100km slices and
is suitable for rendering with mapnik. If opening this in qgis, be sure to
create a spatial index. 

Other coastline sources:
migurski's coastline extracts at http://metro.teczno.com/#coastline  These
are generated approximately every 10 days and include a manually inspected
coastline which is less likely to contain geometry errors.

tile.osm.org extracts at
http://wiki.openstreetmap.org/wiki/Coastline_error_checker#Current_Location
These are generated infrequently and include shoreline_300, a low-resolution
shoreline for low zooms. Having an updated low-zoom coastline is less
important since you shouldn't be able to see most changes.

Technical details:

The programs at http://svn.openstreetmap.org/applications/utils/coastcheck/
are used, along with a script based on doit but modified to upload via scp
and use my xapi instance for generation. The uploaded state.txt files are
from when the run started. The majority of the run is spent uploading the
shapefiles

For today, yesterday's run is at http://maps.paulnorman.ca/coastline/






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