Write new dataset from 2d array in node-gdal-async

Question

I am trying to create a new dataset from a 2d array in JavaScript. However, I can't seem to find my way around the docs to do this.

To create a new dataset, I seem to have to use gdal.open in write mode to be able to write new data, but I am unsure how to update this empty raster with my real data:

const driver = gdal.drivers.get('GTiff');
const xSize = 3;
const ySize = 3;
const bandCount = 1;
const dataType = gdal.GDT_Int32;
const dataset = await gdal.openAsync('output.tif', 'w', driver, xSize, ySize, bandCount, dataType);

Now let's say I have the following 2D array of data:

// from a hdf5 file
const data = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9],
];

How would I update my dataset to have the provided data?

Answer 1

Here is the correct code snippet:

const xSize = 3;
const ySize = 3;
const bandCount = 1;
const dataType = gdal.GDT_Int32;
const dataset = await gdal.openAsync('output.tif', 'w', 'GTiff', xSize, ySize, bandCount, dataType);

const data = new Int32Array([
    1, 2, 3,
    4, 5, 6,
    7, 8, 9,
]);

const band1 = await dataset.bands.getAsync(1);
await band1.pixels.writeAsync(0, 0, xSize, ySize, data);
await dataset.flushAsync();

A few notes:

• This is the fully async code, meaning you will never block the event loop;

• gdal requires that you use TypedArrays. If you want to use multidimensional arrays, I suggest you consider using ndarray and scijs, there is also a plugin for gdal-async;

• There is no closeAsync, but if you call flushAsync you guarantee that the data will be written, even if the file won't be closed until the GC destroys the object.