Uses json-stream-reduce, a fork of tile-reduce that works on large files of line-delimited JSON data to reconstruct historical geometries (both major and minor versions) of OSM objects from JSON input that includes historical node locations.
npm install
node index.js <Line-delimited GeoJSON file with @history and nodeLocations attributes>
This will create a stream of new GeoJSON objects in one of the following formats.
| Type | Description | Recommended Use |
|---|---|---|
Distinct objects with TopoJSON encoded @history |
Each line is an individual OSM object. The histories of each object are encoded (with both minor and major version geometries) as TopoJSON for space-efficiency | Tiling & subsequent analysis with tile-reduce |
| All versions | Every version (minor and major) of every object with validSince and validUntil timestamps |
Visualizing change overtime |
| Distinct objects with full history | @history object as JSON array. Should always use TopoJSON encoding of @history object unless there is a problem with the encoding. |
Debugging |
For each of these outputs, the amount of metadata can be specified. For example, including only the deltas between versions encoded as aA, aM, and aD for attributes added, attributes modified, and attributes deleted, respectively. These options are set in the CONFIG variable in map-geom-reconstruction.js.
element-reconstruction/ includes each of the history reconstructors for each OSM element type. relation-history-builder.js is currently a stub that does not recreate any historical geometries for any relations.