KML Coordinate Density Reducer

by Ben Buckman, New Leaf Digital

Purpose

Given a KML file with more coordinates than necessary, this node script will reduce the coordinates to a requested density.

Written to create maps of my bike routes in Buenos Aires.

Note: This does not actually parse any XML, it simply regex's each line to find coordinates, strips out unwanted ones, and leaves the rest of the lines intact. The algorithm is very "dumb": given a reduce parameter of 2, it keeps every other (1 out of 2) coordinates; with 5, it strips 4/5; etc.

Usage

node ./node-kml-reduce-density.js --in [PATH] --out [PATH] --reduce [NUM]

Options:
  --in      source KML file                                                   [required]
  --out     write to new KML file                                             [required]
  --reduce  Preserve 1/N coordinates. 1=all, 4=25%, 10=10%. Default 2 (50%).  [required]  [default: 2]

Adaptations

• Version that also checks the distance between points: https://gist.github.com/1709189