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wld-bbox

0.0.1
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  • License CC0-1.0

Calculate a Bounding Box given a World File and Raster Size. Super High Precision.

Package Exports

  • wld-bbox
  • wld-bbox/wld-bbox.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (wld-bbox) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

wld-bbox

Calculate a Bounding Box given a World File and Raster Size.

features

  • No floating point arithmetic issues thanks to preciso

limitiations

  • doesn't support World Files with a skew (rotation around the x or y axis)

install

npm install wld-bbox

usage

const calcWorldFileBoundingBox = require("wld-bbox");

const wld = {
  xScale: "2445.9849051249894",
  ySkew: "0",
  xSkew: "0",
  yScale: "-2445.98490512499",
  xOrigin: "7699959.850241235",
  yOrigin: "1323859.6754601842"
};

const size = { height: 475, width: 968 };

const bbox = calcWorldFileBoundingBox({ wld, size });
// bbox is a super-precise bounding box in [xmin, ymin, xmax, ymax] format
// where the numbers are represented as strings for extra precision
// because of the limitations of JavaScript floating point numbers
// ex: Number("7698736.8577886725053") results in 7698736.857788673
["7698736.8577886725053", "163239.837978376445", "10066450.2459496622445", "1325082.667912746695"]

// turn off high-precision and just use quicker floating point arithmetic
const bbox = calcWorldFileBoundingBox({ wld, size, precise: false });
[7698736.857788673, 163239.83797837654, 10066450.245949663, 1325082.6679127468]

To read the data from a World File into an object, consider using wld-reader.