OpenStreetMap (OSM) vs. USGS National Hydrography Dataset (NHD) coverage of rivers,
streams, canals, and other linear hydrography of Washington State
Hydrography layers
To be added soon: USGS 3DHP flowlines
Compare
Boundary layer
Selected area
Click a boundary on the map, or pick one from a list above.
OSM miles
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NHD miles
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OSM / NHD coverage
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OSM by category
NHD by category
About this map
This map compares two separately maintained hydrography datasets covering
Washington State:
OpenStreetMap (OSM) waterways — crowd-sourced line features tagged as
streams, rivers, canals, etc, extracted from the OSM planet dataset.
USGS National Hydrography Dataset (NHD) flowlines — an
authoritative, professionally maintained hydrography dataset produced by the
U.S. Geological Survey.
Note: the difference in terminology (waterways vs. flowlines) simply reflects what each
organization calls these features in its source data.
Boundary layers (counties, and USGS HUC-8 and HUC-10 watersheds) let one select an area and
compare stream mileage between the two datasets within it. Mileage statistics are
precomputed offline from these two datasets and shown in the sidebar when a boundary
is selected.