def localortho(lon, lat):
    """Create srs for local orthographic projection centered at lat, lon
    """
    local_srs = osr.SpatialReference()
    local_proj = '+proj=ortho +lat_0=%0.7f +lon_0=%0.7f +datum=WGS84 +units=m +no_defs ' % (lat, lon)
    local_srs.ImportFromProj4(local_proj)
    return local_srs
Create srs for local orthographic projection centered at lat, lon