Fences-slicer NPM

fences-slicer

Split large geojson file into smaller region files

install

Note: you will need node and npm installed first. The easiest way to install node.js is with nave.sh by executing [sudo] ./nave.sh usemain stable

npm install fences-slicer

usage

preparing regions file

You can feed a geojson file through the fences-regions command to sanitize and prepare the file to be used in the fences-slicer step.

$ fences-regions --inputGeojson=/etc/planet-fences/admin_level_2.geojson --outputFile=./regions.geojson

In order for input regions to show up in output regions they must meet the following requirements:

have name or name:en property
have flag property

You could provide a wanted list of names as a filter. In that case the results will all be names matching the items in the wanted list.

Regions in output will also be simplified (to 0.001).

Output regions will each have the following properties:

name_display : name to be used for display purposes
name : sanitized version of the name that can be used for filenames

standalone utility

When using fences-slicer from the command line, it expects the following config parameters in order to do its job.

Name	Description
`inputDir`	path to the directory containing geojson input files that need to be split into regions. Only `GEOJSON` files will be processed, all others will be skipped. Input files will not be modified.
`outputDir`	path to an existing directory that will contain output files after the slicer is done slicing.
`regionFile`	Geojson file containing regions to be used when slicing. Each region feature must have a `name` in properties.

The expected parameters can be specified via a config file like so:

$ fences-slicer --config=./etc/config.json

sample config file contents

{
  "inputDir": "/some/dir/planet-latest-fences",
  "outputDir": "/some/dir/planet-latest-fences-regions",
  "regionFile": "/some/geojson/file..geojson"
}

If not using a config file, or using a config file but need to override a particular parameter do this:

$ fences-slicer --inputDir=/path/different/from/config --config=./etc/config.json

dependency module

When using fences-slicer in your node.js package as dependency, you need to provide an input file and an array of regions, where each region has an output file and box. See example below.

var slicer = require('fences-slicer');

var param = {
  inputDir: '/some/dir/planet-fences/',
  inputFile: 'planet-level-2.geojson',
  outputDir: '/some/dir/to/throw/output/',
  regionFile: '/etc/my/regions.geojson'
};

slicer.extractRegions(params, function () {
  console.log('fences sliced successfully!');
});