Source code for pygmt.src.grdvolume

grdvolume - Calculate grid volume and area constrained by a contour.
import pandas as pd
from pygmt.clib import Session
from pygmt.exceptions import GMTInvalidInput
from pygmt.helpers import (

[docs]@fmt_docstring @use_alias( C="contour", R="region", S="unit", V="verbose", ) @kwargs_to_strings(C="sequence", R="sequence") def grdvolume(grid, output_type="pandas", outfile=None, **kwargs): r""" Determine the volume between the surface of a grid and a plane. Read a 2-D grid file and calculate the volume contained below the surface and above the plane specified by the given contour (or zero if not given) and return the contour, area, volume, and maximum mean height (volume/area). Alternatively, a range of contours can be specified to return the volume and area inside the contour for all contour values. Full option list at :gmt-docs:`grdvolume.html` {aliases} Parameters ---------- grid : str or xarray.DataArray The file name of the input grid or the grid loaded as a DataArray. output_type : str Determine the format the output data will be returned in [Default is ``pandas``]: - ``numpy`` - :class:`numpy.ndarray` - ``pandas``- :class:`pandas.DataFrame` - ``file`` - ASCII file (requires ``outfile``) outfile : str The file name for the output ASCII file. contour : str or int or float or list *cval*\|\ *low/high/delta*\|\ **r**\ *low/high*\|\ **r**\ *cval*. Find area, volume and mean height (volume/area) inside and above the *cval* contour. Alternatively, search using all contours from *low* to *high* in steps of *delta*. [Default returns area, volume and mean height of the entire grid]. The area is measured in the plane of the contour. Adding the **r** prefix computes the volume below the grid surface and above the planes defined by *low* and *high*, or below *cval* and grid's minimum. Note that this is an *outside* volume whilst the other forms compute an *inside* (below the surface) area volume. Use this form to compute for example the volume of water between two contours. If no *contour* is given then there is no contour and the entire grid area, volume and the mean height is returned and *cval* will be reported as 0. {R} {V} Returns ------- ret : pandas.DataFrame or numpy.ndarray or None Return type depends on ``outfile`` and ``output_type``: - None if ``outfile`` is set (output will be stored in file set by ``outfile``) - :class:`pandas.DataFrame` or :class:`numpy.ndarray` if ``outfile`` is not set (depends on ``output_type`` [Default is class:`pandas.DataFrame`]) """ if output_type not in ["numpy", "pandas", "file"]: raise GMTInvalidInput( """Must specify format as either numpy, pandas, or file.""" ) if output_type == "file" and outfile is None: raise GMTInvalidInput("""Must specify outfile for ASCII output.""") with GMTTempFile() as tmpfile: with Session() as lib: file_context = lib.virtualfile_from_data(check_kind="raster", data=grid) with file_context as infile: if outfile is None: outfile = arg_str = " ".join([infile, build_arg_string(kwargs), "->" + outfile]) lib.call_module("grdvolume", arg_str) # Read temporary csv output to a pandas table if outfile == # if user did not set outfile, return pd.DataFrame result = pd.read_csv(, sep="\t", header=None, comment=">") elif outfile != # return None if outfile set, output in outfile result = None if output_type == "numpy": result = result.to_numpy() return result