GEOIMAGE

A Javascript library for generating bitmaps out of geoTIFF files.

Features

Bitmap generation

• Create RGB pictures out of RGB geoTIFF data.
• Generate pictures out of non-RGB geoTIFF data with different processing options.

Heightmap generation

• Generate heightmaps out of single-channel geoTIFF elevation data.
• The elevation data is encoded into the bitmap as Mapbox Terrain-RGB.

Data visualisation options

• color
• Transparency
• Heatmap
• Data slice
• Automatic data range
• Manual data range

Data processing functions

• setAutoRange(boolean) - set automatic range of color gradient (default true)
• setDataOpacity(boolean) - visualise data with opacity of each pixel according to its value (default false)
• setHeatMap(boolean) - generate data as a color heatmap (default true)
• setDataRange(float min, float max) - manually set gradient range (if setAutoRange is false)
• setColor(int, int, int) - generate data in specific color (if setHeatMap is false)
• setOpacity(int) - visualise data in specific opacity (if setDataOpacity is false)
• setDataClip(float low, float high) - generate data only between low and high

Return options

All methods return processed Image DataUrl

• getBitmap(url | object)
• getHeightmap(url | object)

Returns an image out of valid url pointing to a geotiff file. If the geotiff has 3 or 4 color channels, returns standard RGB or RGBA image. If the geotiff has 1 channel, data get processed according to data processing you set. Instead of url, you also have the option to provide an object containing:

rasters : array; //An array containing all raster arrays of the image. 
width : number; //Width of the image in pixels
height : number; //Height of the image in pixels

Basic example

Initialize the library

import GeoImage from 'geoimage';

const g = new GeoImage();

Get bitmap and bounds

const bitmap = await g.getBitmap('image.tif');
const bounds = g.getBoundingBox();

Get heightmap

const heightmap = await g.getHeightmap('image.tif');

Advanced example

//Import the library and initiate GeoImage object:
import GeoImage from 'geoimage';

const g = new GeoImage();

//Single-channel geotiff as a transparent heatmap with auto-rage:
g.setAutoRange(true);
g.setHeatMap(true);
g.setOpacity(120);
const firstImage = await g.getBitmap('image.tif');

//Single-channel geotiff as a transparent heatmap with manual range in meters:
g.setAutoRange(false);
g.setDataRange(0,250); //Blue at 0m, red at 250m
g.setHeatMap(true);
g.setOpacity(120);
const secondImage = await g.getBitmap('image.tif');

//Single-channel geotiff with data as transparency:
g.setAutoRange(true);
g.setHeatMap(false);
g.setDataOpacity(true);
const thirdImage = await g.getBitmap('image.tif');

//Single-channel geotiff with data slice from 350m to 360m in custom color:
g.setDataClip(350,360); //Clip data outside 350m to 360m
g.setHeatMap(false);
g.setColor(0,255,100);
const fourthImage = await g.getBitmap('image.tif');