georaster

Wrapper around Georeferenced Rasters like GeoTIFF, NetCDF, JPG, and PNG that provides a standard interface. You can also create your own georaster from simple JavaScript objects.

load from url on front-end

const parseGeoraster = require("georaster");
fetch(url)
  .then(response => response.arrayBuffer() )
  .then(parseGeoraster)
  .then(georaster => {
      console.log("georaster:", georaster);
  });

load from file on back-end

const parseGeoraster = require("georaster");
fs.readFile("data/GeogToWGS84GeoKey5.tif", (error, data) => {
    parseGeoraster(data).then(georaster => {
      console.log("georaster:", georaster);
    })
});

load from File (or other Blob) on front-end

const parseGeoraster = require("georaster");
document.querySelector("input").addEventListener("change", e => {
  const file = e.target.files[0];
  parseGeoraster(file)
    .then(georaster => {
      console.log("georaster:", georaster);
    });
});

load from simple object on front-end

const parseGeoraster = require("georaster");
const values = [ [ [0, 1, 2], [0, 0, 0], [2, 1, 1] ] ];
const noDataValue = 3;
const projection = 4326;
const xmin = -40;
const ymax = 14;
const pixelWidth = 0.00001;
const pixelHeight = 0.00001;
const metadata = { noDataValue, projection, xmin, ymax, pixelWidth, pixelHeight };
const georaster = parseGeoraster(values, metadata);

load cloud optimized geotiff

This option (and File with readOnDemand, below) allows you to basically
load the pixels only when you need them versus the other options
that require you to load the whole image into memory. It will also attempt to automatically discover any available overview files.

where to clip

top is how many pixels from the top of the image to skip over before we start clipping

bottom is how many pixels from the bottom of the image to skip over before we start clipping

left is how many pixels in from the left side of the image to skip over before we start clipping

right is how many pixels in from the right side of the image to skip over before we start clipping

clipping resolution

width is how many pixels wide should be the returned image. This helps to configure the resolution.

height is how many pixels tall should be the returned image. This helps to configure the resolution.

resampling

resampleMethod is how to resample the pixels for the returned image. This value is passed on to geotiff.js‘ readRasters function and defaults to ‘bilinear’. The alternative is ‘nearest’, which is faster and better for categorical data like landcover and continous classes with smooth variation like temperature.

  const raster_url = "https://landsat-pds.s3.amazonaws.com/c1/L8/024/030/LC08_L1TP_024030_20180723_20180731_01_T1/LC08_L1TP_024030_20180723_20180731_01_T1_B1.TIF";
  parseGeoraster(raster_url).then(georaster => {
    console.log(georaster.height);
    const options = { left: 0, top: 0, right: 4000, bottom: 4000, width: 10, height: 10 };
    georaster.getValues(options).then(values => {
      console.log("clipped values are", values);
    });
  });

load from File on demand

By default, a File or ArrayBuffer will be read and parsed completely
at full resolution in a worker thread (if available) before
the promise returned by parseGeoraster() is resolved.
If less data is required (such as when the file includes overviews),
then the readOnDemand option allows reading and parsing to be deferred
until getValues() is called.

  parseGeoraster(file, { readOnDemand: true })
    .then(georaster => georaster.getValues(options))
    .then(values => ...

required properties

optional properties

functions

loading georaster package through a script tag

<script src="https://unpkg.com/georaster"></script>

You can view a simple demo of this here

Support

Post a Github issue or contact the package author, Daniel J. Dufour, at daniel.j.dufour@gmail.com