Determining coordinates of corners of raster layer using PyQGIS?

How can we determine the coordinates of the corners of the raster layer?

The image opens function QgsRasterLayer.

Answer

I have just found the following snippet, it might be what you are looking for:

from osgeo import gdal, osr

bag = gdal.Open('F00574_MB_2m_MLLW_2of3.bag')  # replace it with your file
                                               # raster is projected

bag_gtrn = bag.GetGeoTransform()
bag_proj = bag.GetProjectionRef()
bag_srs = osr.SpatialReference(bag_proj)
geo_srs =bag_srs.CloneGeogCS()                 # new srs obj to go from x,y -> φ,λ
transform = osr.CoordinateTransformation( bag_srs, geo_srs)

bag_bbox_cells = (
    (0., 0.),
    (0, bag.RasterYSize),
    (bag.RasterXSize, bag.RasterYSize),

    (bag.RasterXSize, 0),
  )

geo_pts = []
for x, y in bag_bbox_cells:
    x2 = bag_gtrn[0] + bag_gtrn[1] * x + bag_gtrn[2] * y
    y2 = bag_gtrn[3] + bag_gtrn[4] * x + bag_gtrn[5] * y
    geo_pt = transform.TransformPoint(x2, y2)[:2]
    geo_pts.append(geo_pt)
    print x, y, '->', x2, y2, '->', geo_pt

The results of this code are:

# Pixel Coord ->     Proj Coords    ->    (φ,λ) coords
0.0 0.0       -> 369179.0 4775259.0 -> (-70.608087740520943, 43.118768822635147)                                
0.0 1083      -> 369179.0 4773093.0 -> (-70.607577288471774, 43.099271863165256)                               
1841 1083     -> 372861.0 4773093.0 -> (-70.56234820699548, 43.099898472783011)                               
1841 0.0      -> 372861.0 4775259.0 -> (-70.562844311963829, 43.119395856927362)