@weacast/gtiff2json

A command line utility that decodes GeoTIFF files as JSON.

This utility uses the native GDAL binding for Node.js : node-gdal.

This work is highly inspired from geotiff2json but extends it to support:

• simple JSON conversion without RLE encoding
• any block size in TIFF files (not just squares)

Installation

npm install -g @weacast/gtiff2json

Usage

As CLI

The gtiff2json CLI can be used similarly from the native OS CLI or from Node.

> grib2json --help (or node bin.js --help)
Usage: grib2json (or node bin.js) [options] <file>
  -V, --version                output the version number
  -c, --compress               Output RLE compressed JSON
  -r, --round                  Round values to nearest integer when performing RLE compression
  -p, --precision <precision>  Limit precision in JSON using the given number of digits after the decimal point (default: -1)
  -o, --output <file>          Output in a file instead of stdout
  -v, --verbose                Verbose mode for debug purpose
  -h, --help                   output usage information

As module

Here's an example that converts file.tif into a JSON array and writes it to disk as data.json:

  const geotiff2json = require('@weacast/gtiff2json')
  const fs = require('fs')
  
  geotiff2json('file.tif').then(function(data) {
    fs.writeFile('data.json', JSON.stringify(data), function(err) {
      if(err) {
        console.error('Oh no, writing failed!', err)
        return
      }
    })
  })

Here's an example that converts file.tif into an RLE value array and writes it to disk as data.json:

  const geotiff2json = require('@weacast/gtiff2json')
  const fs = require('fs')
  
  geotiff2json('file.tif', true).then(function(data) {
    fs.writeFile('data.json', JSON.stringify(data), function(err) {
      if(err) {
        console.error('Oh no, writing failed!', err)
        return
      }
      console.log('wrote ' + (data.length / 2) + ' tuples into file.')
  })

The output file's content will look similar to this:

  [
    100,10,
    132,1,
    80,5,
    ...
  ]

Note: The linebreaks and whitespace have been added for better readability, the file won't contain those to reduce size.

These values are in fact value pairs.

• The first value of each pair is the y-coordinate of the point.
• The second value of each pair is the number of times this y-coordinate is repeated.

So in the example above, the y-value 100 shall be repeated 10 times, the y-value 132 shall be repeated once and so on..

Contribute

If you find a bug or a problem or data that doesn't parse correctly, even though it should, please report an issue here.

In case you found a GeoTIFF that doesn't parse correctly, please attach a link to the file or attach it to the issue directly.

If you have improvement suggestions, feel free to fork this repository and submit a pull request.

Thank you for your help and support.