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Using Washington State DNR LiDAR imagery in the iD editor

Posted by jake-low on 20 July 2021 in English (English).

Washington State’s Department of Natural Resources collects and publishes LiDAR data covering much of the state. LiDAR imagery is created by flying specially-equipped aircraft over areas of interest and using light pulses to determine the precise distance to the ground. This data is later assembled into elevation maps. You can browse the maps using the DNR LiDAR Portal interactive viewer.

The LiDAR maps are very high resolution (about 2 meters per pixel). In addition, LiDAR penetrates tree cover to reveal the shape of the ground hidden underneath. These attributes make LiDAR data a great resource for mapping streams, hiking trails, and forest roads.

LiDAR map of Clark Mountain area, showing glaciers and streams

Above: Clark Mountain area, showing glaciers and streams

Below: Paradise in Mount Rainier National Park, showing roads, parking lot and hiking trails.

LiDAR map of Paradise in Mount Rainier National Park, showing roads, parking lot and hiking trails

All of the DNR LiDAR maps are in the public domain, so it be used without worry when contributing to OSM. About one-third of the state has already been surveyed, and the DNR plans to survey the entire state.

Map showing statewide coverage of LiDAR data in Washington

Using DNR LiDAR maps in iD is very simple. The DNR runs an ArcGIS server which provides a WMS endpoint. iD can use this endpoint to display a custom imagery layer.

Launch iD ( Open the Background Settings panel on the right (shortcut: B), choose “Custom” from the Backgrounds list, and then paste this text into the box in the pop-up that appears:{height}&width={width}&srs=EPSG%3A3857&bbox={bbox}

That template string tells iD how to query the DNR’s WMS server. Click “OK” and you should see the imagery appear right away.

Screenshot of iD editor showing a LiDAR basemap

Special thanks to the following people:

  • Glassman, for making me aware of the existence of the DNR LiDAR data portal in the first place.
  • Tony Cannistra, for sharing the WMS endpoint template string shown above. I had been using a much more complex workflow involving MapProxy to proxy the WMS endpoint in a TMS-compatible form; Tony’s comment made me realize you could simply use the WMS endpoint in iD directly.
  • 1ec5, who actually added support for WMS endpoints in iD (awesome!).