Regarding the updates to OSM by 4 Trimet interns, in 4 counties around Portland, Oregon...<br><br>Our updated workflow is still in testing, but we have found this to work, albeit, slowly.<br><br>Using ArcMap 10, we are creating reference geodatabases in which to organize and store our jurisdictional data.<br>
- Includes most recent streets & trails data from RLIS for Washington, Multnomah, Clark, and Clackamas County.<br>- Projected in WGS 1984 to match OSM's exported data.<br>- Attribute fields for streets and trails are deleted or edited to match OSM tags. The attribute conversion maps are not yet finalized.<br>
<br>County datasets are created<br>- Streets & trails inside or within 1 km of the county boundary <br>- 10 foot buffers are created around streets and trails per county. Buffered trails & streets are merged.<br>
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County data is converted to OSM format<br>- Using an ogr-to-osm Java-based script, we convert county streets and trails to .osm<br>- In JOSM, several attribute fields have to be edited since ArcMap limits field characters and several OSM tags have lengthy keys.<br>
<br>Download OSM data<br>- Nightly, we download West Coast data from Geofabrik.<br>- The data is broken up into the counties and sub-county portions (5 - 15M sizes) by Osmosis. This allows quicker upload into ArcMap (5 - 10 min)<br>
<br>Create a "diff" file (difference) - includes only OSM highway lines that are over 10 feet from jurisdictional data.<br>- In ArcMap 10, with OSM Editor extension, we load a sub-county area and symbolize lines.<br>
- Select by location all OSM highway lines that are within the 10 foot buffered jurisdictional data. Invert selection, and export as our "diff" file.<br>- Convert to osm using ogr-to-osm script<br>- As errors are resolved, the problem features are deleted from the diff file to track our process<br>
<br>Load files in JOSM, in order from top to bottom:<br>- area OSM data<br>- jurisdictional streets data<br>- jurisdictional trails data<br>- diff file<br>- gpx version of diff file (better control of symbology but unable to edit gpx)<br>
- aerials<br><br>Edit in JOSM<br>- using bright symbology, the diff file highlights OSM data that needs to be checked.<br>- we use aerials, OSM tags, and common sense to see if OSM or jurisdictional data is correct.<br><br>
If feature exists in OSM but is incorrect, either in tags, directionality, or geometry:<br>- make sure to maintain OSM tags while adding jurisdictional tags (copy/paste from OSM to jurisdictional, then copy/paste all tags from jurisdictional to OSM)<br>
- check geometry and alignment based on jurisdictional data and aerials<br>- Delete edited feature from Diff file<br> <br>If feature doesn't exist in OSM: <br>- copy/paste feature from jurisdictional data to Area OSM layer.<br>
- Merge node(s) as needed to connect the updated feature with the surrounding features. Check against aerials.<br>- Delete edited feature from Diff layer.<br><br>If jurisdictional data is incorrect, we will track the local IDs of the features and provide feedback to the jurisdiction who maintains the data.<br>
<br>--<br>PJ Houser<br>Trimet<br>
GIS intern, 503-962-5711 (office)<br>