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index.js
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index.js
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#!/usr/bin/env node
const ps = require('@kalisio/geo-pixel-stream')
const fs = require('fs')
const program = require('commander')
function readGeoTiff (filePath, verbose) {
let promise = new Promise(function (resolve, reject) {
let readers = ps.createReadStreams(filePath)
let blocks = []
if (verbose) {
console.log('File metadata :')
console.log(readers[0].metadata)
}
readers[0].on('data', function (data) {
let blockPoints = []
let blockLen = data.blockSize.x * data.blockSize.y
for (let i = 0; i < blockLen; i++) { blockPoints.push(data.buffer[i]) }
blocks.push(blockPoints)
})
readers[0].on('end', function () {
// Force closing underlying GDAL dataset immediately (not waiting for GC) as it might be large
readers[0]._src.close()
resolve({ blocks: blocks, metadata: readers[0].metadata })
})
})
return promise
}
function linearize (blocks, blockWidth, blocksPerRow, blockHeight, blocksPerCol, verbose) {
let points = []
if (verbose) {
console.log('Found ' + blocks.length + ' blocks of ' + blocks[0].length + ' points')
console.log('Linearize ' + blocksPerRow + ' blocks per row of width ' + blockWidth)
}
for (let row = 0; row < blockHeight * blocksPerCol; row++) {
for (let col = 0; col < blockWidth * blocksPerRow; col++) {
// let col = i % (blockWidth * blocksPerRow), row = Math.floor(i / (blockHeight * blocksPerCol))
let block = Math.floor(col / blockWidth) + Math.floor(row / blockHeight) * blocksPerRow
let colInBlock = col % blockWidth
let rowInBlock = row % blockHeight
// console.log(row, col, block, colInBlock, rowInBlock)
points[col + row * blockWidth * blocksPerRow] = blocks[block][colInBlock + rowInBlock * blockWidth]
}
}
if (verbose) {
console.log('Linearized ' + points.length + ' points.')
}
return points
}
function compressRLE (points, round, verbose) {
let output = []
let currentValue = points[0]
let currentLen = 1
if (round) {
currentValue = Math.round(currentValue)
}
for (let i = 1, len = points.length; i < len; i++) {
let value = points[i]
if (round) {
value = Math.round(value)
}
if (value === currentValue) currentLen++
else {
output.push(currentValue)
output.push(currentLen)
currentValue = value
currentLen = 1
}
}
if (verbose) {
console.log('Compressed to ' + output.length + ' points.')
}
return output
}
var gtiff2json = function (filePath, compress, round, verbose) {
let promise = new Promise(function (resolve, reject) {
readGeoTiff(filePath, verbose).then(function (data) {
return linearize(data.blocks, data.metadata.blockSize.x, Math.max(1, data.metadata.width / data.metadata.blockSize.x),
data.metadata.blockSize.y, Math.max(1, data.metadata.height / data.metadata.blockSize.y), verbose)
})
.then(function (points) {
if (!compress) {
resolve(points)
} else {
resolve(compressRLE(points, round, verbose))
}
})
.catch(function (err) {
reject(err)
})
})
return promise
}
if (require.main === module) {
program
.version(require('./package.json').version)
.usage('<file> [options]')
.option('-c, --compress', 'Output RLE compressed JSON')
.option('-r, --round', 'Round values to nearest integer when performing RLE compression')
.option('-p, --precision <precision>', 'Limit precision in JSON using the given number of digits after the decimal point', -1)
.option('-o, --output <file>', 'Output in a file instead of stdout')
.option('-v, --verbose', 'Verbose mode for debug purpose')
.parse(process.argv)
var inputFile = program.args[0]
program.precision = parseInt(program.precision)
var numberFormatter = function (key, value) {
return ((program.precision >= 0) && value.toFixed) ? Number(value.toFixed(program.precision)) : value
}
gtiff2json(inputFile, program.compress, program.round, program.verbose).then(function (points) {
if (program.output) {
fs.writeFile(program.output, JSON.stringify(points, numberFormatter), function (err) {
if (err) {
console.error('Writing output file failed : ', err)
return
}
if (program.verbose) {
console.log('Wrote ' + points.length + ' points into file.')
}
})
} else {
console.log(points)
}
})
.catch(function (err) {
console.log(err)
})
} else {
module.exports = gtiff2json
}