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Eric Fischer 2017-10-10 16:46:47 -07:00
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@ -615,3 +615,60 @@ resolutions.
* `-c` or `--tag-layer-and-zoom`: Include each feature's layer and zoom level as part of its `tippecanoe` object rather than as a FeatureCollection wrapper
* `-S` or `--stats`: Just report statistics about each tile's size and the number of features in it, as a JSON structure.
* `-f` or `--force`: Decode tiles even if polygon ring order or closure problems are detected
tippecanoe-json-tool
====================
Extracts GeoJSON features or standalone geometries as line-delimited JSON objects from a larger JSON file,
following the same extraction rules that Tippecanoe uses when parsing JSON.
tippecanoe-json-tool file.json [... file.json]
Optionally also wraps them in a FeatureCollection or GeometryCollection as appropriate.
Optionally extracts an attribute from the GeoJSON `properties` for sorting.
Optionally joins a sorted CSV of new attributes to a sorted GeoJSON file.
The reason for requiring sorting is so that it is possible to work on CSV and GeoJSON files that are larger
than can comfortably fit in memory by streaming through them in parallel, in the same way that the Unix
`join` command does. The Unix `sort` command can be used to sort large files to prepare them for joining.
### Options
* `-w` or `--wrap`: Add the FeatureCollection or GeometryCollection wrapper.
* `-e` *attribute* or `--extract=`*attribute*: Extract the named attribute
* `-c` *file.csv* or `--csv=`*file.csv*: Join properties from the named sorted CSV file, using its first column as the join key.
### Example
Join Census LEHD ([Longitudinal Employer-Household Dynamics]) employment data to a file of Census block geography
for Tippecanoe County, Indiana.
Download Census block geometry, and convert to GeoJSON:
```
$ curl -L -O https://www2.census.gov/geo/tiger/TIGER2010/TABBLOCK/2010/tl_2010_18157_tabblock10.zip
$ unzip tl_2010_18157_tabblock10.zip
$ ogr2ogr -f GeoJSON tl_2010_18157_tabblock10.json tl_2010_18157_tabblock10.shp
```
Download employment data, and fix name of join key in header
```
$ curl -L -O https://lehd.ces.census.gov/data/lodes/LODES7/in/wac/in_wac_S000_JT00_2015.csv.gz
$ gzip -dc in_wac_S000_JT00_2015.csv.gz | sed '1s/w_geocode/GEOID10/' > in_wac_S000_JT00_2015.csv
```
Sort GeoJSON block geometry so it is ordered by block ID. If you don't do this, you will get a
"GeoJSON file is out of sort" error.
```
$ tippecanoe-json-tool -e GEOID10 tl_2010_18157_tabblock10.json | LC_ALL=C sort > tl_2010_18157_tabblock10.sort.json
```
Join block geometries to employment properties:
```
$ tippecanoe-json-tool -c in_wac_S000_JT00_2015.csv tl_2010_18157_tabblock10.sort.json > blocks-wac.json
```