geowarp
Super Low-Level Raster Reprojection and Resampling Library
install
npm install -S geowarp
usage
const geowarp = require("geowarp");
const proj4 = require("proj4-fully-loaded");
const result = geowarp({
// control the level of console log output
// set debug_level to zero to turn off console logging
debug_level: 2,
// reproject from an [x, y] point in the output spatial reference system
// to an [x, y] point in the input spatial reference system
reproject: proj4("EPSG:" + 3857, "EPSG:" + in_srs).forward,
// two-dimensional array of pixel data organized by band
// usually [ r, g, b ] or [ r, g, b, a ]
// pixel data for each band is usually flattened,
// so the end of one row is immediately followed by the next row
in_data: [
[0, 123, 123, 162, ...],
[213, 41, 62, 124, ...],
[84, 52, 124, 235, ...]
],
// bounding box of input data (in_data)
// in [xmin, ymin, xmax, ymax] format
in_bbox: [ -122.51, 40.97, -122.34, 41.11 ],
// a number or string representing the spatial reference system of the input data
// could be 4326 or "EPSG:4326"
in_srs: 4326,
// how many pixels wide the input data is
in_width: 1032,
// how many pixels tall the input data is
in_height: 1015,
// bounding box of output
// this is the space that you want to paint
// in same format as in_bbox
out_bbox: [-13638811.83098057, 5028944.964938315, -13619243.951739563, 5028944.964938315],
// a number or string representing the spatial reference system of the input data
// could be 4326 or "EPSG:4326"
out_srs: 3857,
// height of the output image in pixels
out_height: 256,
// width of the output image in pixels
out_width: 256,
// method to use to sample the pixels
// current supported methods are:
// "max", "mean", "median", "min", "mode", "mode-max", "mode-mean", "mode-median", and "mode-min"
method: 'median',
// round output pixel values to closest integer
// do this if you will convert your output to a PNG or JPG
round: true,
// optional
// the lowest possible pixel value considering the bit-depth of the data
// this is used to speed up the min and mode-min resampling
// if in_data is an array of typed arrays, this will be automatically calculated
theoretical_min: 0,
// optional
// the highest possible pixel value considering the bit-depth of the data
// this is used to speed up the max and mode-max resampling
// if in_data is an array of typed arrays, this will be automatically calculated
theoretical_max: 255
});
// result.data is a 3-dimensional array of pixel values broken down by row then column the band
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