Southeast Alaska Hydrography

Getting National Hydrography Data - NHD - into OpenStreetMap

The current coastline in OpenStreetMap is lacking in detail for much of Alaska, particularly the very coastal, Southeast Alaska.

Jaggedy coastlines

Myriad Islands - as they appeared in OSM June 2019

I’d like to use National Hydrography Data to improve the entirety of Southeast Alaska in OpenStreetMap. Here is a side-by-side comparison map that shows current OpenStreetMap data (as of 2019-06-07) with NHD data.

OSM / NHD Comparison

The coastline has been my particular interest ever since I started editing the map.

Before/after of coastline around Sitka area

Before and after photos of Sitka, AK coastline photos from ~2013

The current data covers lakes and streams so I hope to include that as well during this import process.

There’s a history of importing NHD into OpenStreetMap, but for Alaska’s coastline it seems untouched by any National Hydrography Data. Recent improvements to Alaska’s hydrography data make now a better time than ever to import data. The Alaska Hydrography Technical Working Group has taken initiative to streamline updating the data for Alaska and making it easily accessible. I had come across hydrology data before and this is a big improvement over previous data for Alaska.

OpenStreetMap’s wiki page on National Hydrography Dataset ultimately discourages imports but I think as far as coastline it will be a huge improvement. It also seems that the data for Alaska is quite good and missing from the map for the most part, so it won’t be a hassle to add features. I aim to use this data to improve much of my surrounding area and I know a few mappers in my area who are highly supportive of this project. I plan on discussing the project with the OSM-imports mailing list.

I will post a diary entry with an update on the project.