shapefile/shp/polyline.js

An implementation of the shapefile (.shp) spatial data format.

export default function(record) {
  var i = 44, j, n = record.getInt32(36, true), m = record.getInt32(40, true), parts = new Array(n), points = new Array(m);
  for (j = 0; j < n; ++j, i += 4) parts[j] = record.getInt32(i, true);
  for (j = 0; j < m; ++j, i += 16) points[j] = [record.getFloat64(i, true), record.getFloat64(i + 8, true)];
  return n === 1
      ? {type: "LineString", coordinates: points}
      : {type: "MultiLineString", coordinates: parts.map(function(i, j) { return points.slice(i, parts[j + 1]); })};
};