"copy and pasted from: https://stackoverflow.com/questions/2922532/obtain-latitude-and-longitude-from-a-geotiff-file"

"obtain lat and long from tif"

from osgeo import osr, gdal

# get the existing coordinate system
ds = gdal.Open('test.tif')
old_cs= osr.SpatialReference()
old_cs.ImportFromWkt(ds.GetProjectionRef())

# create the new coordinate system
wgs84_wkt = """
GEOGCS["WGS 84",
    DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.257223563,
            AUTHORITY["EPSG","7030"]],
        AUTHORITY["EPSG","6326"]],
    PRIMEM["Greenwich",0,
        AUTHORITY["EPSG","8901"]],
    UNIT["degree",0.01745329251994328,
        AUTHORITY["EPSG","9122"]],
    AUTHORITY["EPSG","4326"]]"""
new_cs = osr.SpatialReference()
new_cs .ImportFromWkt(wgs84_wkt)

# create a transform object to convert between coordinate systems
transform = osr.CoordinateTransformation(old_cs,new_cs) 

#get the point to transform, pixel (0,0) in this case
width = ds.RasterXSize
height = ds.RasterYSize
gt = ds.GetGeoTransform()
minx = gt[0]
miny = gt[3] + width*gt[4] + height*gt[5]
maxx = gt[0] + width*gt[1] + height*gt[2]
maxy = gt[3]

#get the coordinates in lat long
latlong = transform.TransformPoint(minx,miny)
maxlatlong = transform.TransformPoint(maxx,maxy)
