Extract corner coordinates of polygon extent in PyQGIS / GDAL

Question

My goal is to extract corner coordinates (i.e. UpperLeft, UpperRight, LowerRight, LowerLeft) from polygon extent using PyQGIS or GDAL.

In ArcPy there is a handy property of an extent class (i.e. feature['SHAPE@'].extent.upperLeft), but is there something similar in PyQGIS / GDAL?

Answer 1

With PyQGIS you can use following code:

layer = iface.activeLayer()

feats = [ feat for feat in layer.getFeatures() ]

for i, feat in enumerate(feats):
    bbox = feat.geometry().boundingBox()
    xmin,ymin,xmax,ymax = bbox.toRectF().getCoords()
    print xmin, ymin, xmax, ymax

Editing Note:

layer = iface.activeLayer()

feats = [ feat for feat in layer.getFeatures() ]

for i, feat in enumerate(feats):
    bbox = feat.geometry().boundingBox()
    xmin,ymin,xmax,ymax = bbox.toRectF().getCoords()
    print xmin, ymin, xmax, ymax
    topLeft = (xmin, ymax)
    bottomRight = (xmax, ymin)

    print topLeft, bottomRight

Answer 2

from osgeo import gdal

ds = gdal.Open(fn)
ulx, width, xrot, uly, yrot, height  = ds.GetGeoTransform()
lrx = ulx + (ds.RasterXSize * width)
lry = uly + (ds.RasterYSize * height)

where: ulx and uly are the upper left corner coordinates and lrx and lry are the lower right corner coordinates.

GetGeoTransform() returns a tuple with the following elements:

1. Origin x coordinate
2. Pixel width
3. x pixel rotation
4. Origin y coordinate
5. y pixel rotation
6. Pixel height