Convert between pixel/geo values with a gdal geotransform

geotransform.py

"""
Where transform is a geotransform array, e.g.
>>> from osgeo import gdal
>>> src = gdal.Open('example.tiff')
>>> transform = src.GetGeoTransform()
>>> (-82.254, 3.0858676207514586e-05, 0.0, 41.3163, 0.0, -3.086680761099182e-05)
>>> # [x origin (left), pixel width, x skew, y origin (top), y skew, y pixel height (negative because counting from top of image)]
"""
def px2geo(geotransform, coord):
    '''Convert pixel coordinates to projected geographic coordinates.'''
    mx, my = coord
    px = mx * geotransform[1] + geotransform[0]
    py = my * geotransform[5] + geotransform[3]
    return px, py

def geo2px(geotransform, point):
    '''Convert geographic coordinates to pixel values.'''
    x_origin, y_origin = transform[0], transform[3]
    width, height = transform[1], -transform[5]
    px = int((point[0] - x_origin) / width)
    py = int((y_origin - point[1] ) / height)
    return px, py