warplib.py 文件源码

def parse_res(res, src_ds_list=None, t_srs=None):
    """Parse arbitrary input res 

    Parameters
    ----------
    res : str or gdal.Dataset or filename or float
        Arbitrary input res 
    src_ds_list : list of gdal.Dataset objects, optional
        Needed if specifying 'first' or 'last'
    t_srs : osr.SpatialReference() object 
        Projection for res calculations, optional

    Returns
    -------
    res : float 
        Output resolution
        None if source resolution should be preserved
    """
    #Default to using first t_srs for res calculations
    #Assumes src_ds_list is not None
    t_srs = parse_srs(t_srs, src_ds_list)

    #Valid strings
    res_str_list = ['first', 'last', 'min', 'max', 'mean', 'med']

    #Compute output resolution in t_srs
    if res in res_str_list and src_ds_list is not None:
        #Returns min, max, mean, med
        res_stats = geolib.get_res_stats(src_ds_list, t_srs=t_srs)
        if res == 'first':
            res = geolib.get_res(src_ds_list[0], t_srs=t_srs, square=True)[0]
        elif res == 'last':
            res = geolib.get_res(src_ds_list[-1], t_srs=t_srs, square=True)[0]
        elif res == 'min':
            res = res_stats[0]
        elif res == 'max':
            res = res_stats[1]
        elif res == 'mean':
            res = res_stats[2]
        elif res == 'med':
            res = res_stats[3]
    elif res == 'source':
        res = None
    elif isinstance(res, gdal.Dataset):
        res = geolib.get_res(res, t_srs=t_srs, square=True)[0]
    elif isinstance(res, str) and os.path.exists(res): 
        res = geolib.get_res(gdal.Open(res), t_srs=t_srs, square=True)[0]
    else:
        res = float(res)
    return res