API · C++ CLASSES · GCP
GCP
A ground-control point: a pixel/line in an image tied to a world coordinate. Collect several, fit a geotransform, and attach them to a dataset to georeference a raw image.
Usage
const gcps = await Module.toArray(await ds.getGCPs());
for (const gcp of gcps) {
console.log(
await gcp.getPixel(), await gcp.getLine(),
"maps to", await gcp.getX(), await gcp.getY(),
);
}Constructor
// x, y, z = world coords; pixel, line = image coords; info, id optional
const gcp = new GCP(28.85, 41.12, 0, 0, 0, "", "");
new GCP(x, y, z, pixel, line, info, id), where info and
id default to "".
Fields
| ACCESSOR | DESCRIPTION |
|---|---|
getX() · getY() · getZ() →
double
|
World coordinate; setters setX/setY/setZ(value). |
getPixel() · getLine() → double |
Image coordinate; setters setPixel/setLine(value). |
getInfo() · getId() → string |
Free-text info and id; setters setInfo/setId(value). |
Fit a geotransform
Pass an array of GCPs to
Gdal.gcpsToGeoTransform(gcps, geoTransform, approxOK), or attach them with
ds.setGCPs(gcps, projection). The examples have a full georeferencing recipe.