bojko108 / dem-reader

Module for extracting elevation data from GeoTIFF files

dem-reader

This library can be used for extracting elevation data from a local GeoTIFF file.

Install

You can install it with NPM (npm install bojko108/dem-reader) or Yarn (yarn add bojko108/dem-reader) and then:

import DemReader from 'dem-reader';

Calculate elevation values

You can calculate elevation values for single points or GeoJSON geometries. Geometries are modified in place, meaning that the elevation value is appended to coordinates array as third element! Following GeoJSON geometries are supported:

• Point
• LineString
• MultiLineString

Coordinates must be either geographical or in GeoTIFF file's coordinate system. If you pass geographical coordinates, the DEM file must be in UTM35 projection (or in WGS84) as the library supports only this projection for now.

Single points

import DemReader from 'dem-reader';

const file = 'path/to/GeoTIFF/file';
const point = [42.60788543745605, 23.35463742347579];

const dem = await DemReader.fromFile(file);

const elevation = await dem.getElevationForPoint(point, 'EPSG:4326');
// elevation is: 812.4079 meters

GeoJSON geometries

Point

import DemReader from 'dem-reader';

const file = 'path/to/GeoTIFF/file';
const point = {
  type: 'Point',
  coordinates: [23.237647338683313, 42.658865111793808]
};

const dem = await DemReader.fromFile(file);

await dem.calculateElevationForGeometry(point, 'EPSG:4326');
// point is now:
// {
//   type: 'Point',
//   coordinates: [23.237647338683313, 42.658865111793808, 664.9458]
// }

LineString

import DemReader from 'dem-reader';

const file = 'path/to/GeoTIFF/file';
const line = {
  type: 'LineString',
  coordinates: [...]
};

const dem = await DemReader.fromFile(file);

await dem.calculateElevationForGeometry(line, 'EPSG:4326');
// line now has elevation values

MultiLineString

import DemReader from 'dem-reader';

const file = 'path/to/GeoTIFF/file';
const multiLine = {
  type: 'MultiLineString',
  coordinates: [...]
};

const dem = await DemReader.fromFile(file);

await dem.calculateElevationForGeometry(multiLine, 'EPSG:4326');
// multiLine now has elevation values

Dependencies

• geotiffjs
• transformations

License

dem-reader is MIT License @ bojko108