Vermont Towns Import

Goals

Add and correct town, county, and village boundaries for Vermont, USA.

Data source and approval

The data source is the BoundaryOther_BNDHASH dataset from VCGI. It is available at http://vcgi.vermont.gov/warehouse/search_tools . Source was last updated February 16, 2012.

The general license for the data is too ambiguous for OSM, so specific permission was obtained by email:

"There is no problem with taking the BNDHASH data and adding it to OSM as long as you attribute VT Center for Geographic Information and the State of VT as the source."

- David F. Brotzman, 08/07/2012

Dataset preprocessing

Original Format

Files used from the data set were Boundary_BNDHASH_region_towns.shp, Boundary_BNDHASH_region_villages.shp, and Boundary_BNDHASH_region_counties.shp

ogr2osm

Files were individually processed using ogr2osm. The specific translation files were very simple (removed all tags except name, added place, boundary, and admin_level)

JOSM-based processing

Lots of manual processing here:

• All boundaries were converted to multipolygons
• Ways were split and combined to have no overlapping or duplicated segments

Import process

All elements in a bounding box around Vermont that contain either boundary=administrative or place=* will be downloaded. Any that are covered by data in the import will be deleted.

The current borders with Canada, New York, New Hampshire, and Massachusetts will be left as-is. Where existing data for VT town borders intersect, nodes will be removed. Where new data for town borders intersect, nodes will be added. This process will be done by hand.

Note: At the Canadian border, existing OSM data and the data in this import match very well, using the same nodes in positions differing by only a few cm. At the borders with other states, the VCGI data, data available from the other state, and existing OSM data all differ.

Updates

No specific updates are planned. The source is updated infrequently and irregularly. The source has extensive metadata about changes that should make any updates very simple.