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Merge pull request #361 from DanielJDufour/get-skewed-bounding-box
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improved getBoundingBox support for skewed/rotated images
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constantinius authored May 8, 2023
2 parents 7dc35ad + 89c00ca commit f15d770
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Showing 3 changed files with 50 additions and 13 deletions.
54 changes: 42 additions & 12 deletions src/geotiffimage.js
Original file line number Diff line number Diff line change
Expand Up @@ -889,21 +889,51 @@ class GeoTIFFImage {
* @returns {Array<number>} The bounding box
*/
getBoundingBox() {
const origin = this.getOrigin();
const resolution = this.getResolution();
const height = this.getHeight();
const width = this.getWidth();

if (this.fileDirectory.ModelTransformation) {
// eslint-disable-next-line no-unused-vars
const [a, b, c, d, e, f, g, h] = this.fileDirectory.ModelTransformation;

const corners = [
[0, 0],
[0, height],
[width, 0],
[width, height],
];

const projected = corners.map(([I, J]) => [
d + (a * I) + (b * J),
h + (e * I) + (f * J),
]);

const xs = projected.map((pt) => pt[0]);
const ys = projected.map((pt) => pt[1]);

return [
Math.min(...xs),
Math.min(...ys),
Math.max(...xs),
Math.max(...ys),
];
} else {
const origin = this.getOrigin();
const resolution = this.getResolution();

const x1 = origin[0];
const y1 = origin[1];
const x1 = origin[0];
const y1 = origin[1];

const x2 = x1 + (resolution[0] * this.getWidth());
const y2 = y1 + (resolution[1] * this.getHeight());
const x2 = x1 + (resolution[0] * this.getWidth());
const y2 = y1 + (resolution[1] * this.getHeight());

return [
Math.min(x1, x2),
Math.min(y1, y2),
Math.max(x1, x2),
Math.max(y1, y2),
];
return [
Math.min(x1, x2),
Math.min(y1, y2),
Math.max(x1, x2),
Math.max(y1, y2),
];
}
}
}

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2 changes: 1 addition & 1 deletion test/data/setup_data.sh
Original file line number Diff line number Diff line change
Expand Up @@ -81,7 +81,7 @@ gdal_translate -of GTiff -co NBITS=16 -ot Float32 -co TILED=YES initial.tiff flo
gdal_translate -of GTiff -co NBITS=16 -ot Float32 -co INTERLEAVE=BAND initial.tiff float_n_bit_interleave_16.tiff || true

# GDAL_METADATA support
wget https://github.com/GeoTIFF/test-data/archive/8ac198032d8b02160049ca161e8108e3d38176f3.zip -O geotiff-test-data.zip
wget https://github.com/GeoTIFF/test-data/archive/6ec42abc044a6884037c148d67a87a5d28228ce5.zip -O geotiff-test-data.zip
unzip -j -o geotiff-test-data.zip "test-data-*/files/*" -d .
rm geotiff-test-data.zip

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7 changes: 7 additions & 0 deletions test/geotiff.spec.js
Original file line number Diff line number Diff line change
Expand Up @@ -538,6 +538,13 @@ describe('Geo metadata tests', async () => {
expect(image.getGeoKeys()).to.have.property('GeographicTypeGeoKey');
expect(image.getGeoKeys().GeographicTypeGeoKey).to.equal(4326);
});

it('should be able to get the bounding box of skewed images', async () => {
const tiff = await GeoTIFF.fromSource(createSource('umbra_mount_yasur.tiff'));
const image = await tiff.getImage();
expect(image.getBoundingBox()).to.be.an('array');
expect(image.getBoundingBox()).to.be.deep.equal([336494.9320674397, 7839364.913043569, 337934.4836350695, 7840804.464611199]);
});
});

describe('GDAL_METADATA tests', async () => {
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