pygmt.blockmedian(table, outfile=None, **kwargs)[source]

Block average (x,y,z) data tables by median estimation.

Reads arbitrarily located (x,y,z) triples [or optionally weighted quadruples (x,y,z,w)] from a table and writes to the output a median position and value for every non-empty block in a grid region defined by the region and spacing arguments.

Full option list at


  • I = spacing

  • R = region

  • table (pandas.DataFrame or str) – Either a pandas dataframe with (x, y, z) or (longitude, latitude, elevation) values in the first three columns, or a file name to an ASCII data table.

  • spacing (str) – 'xinc[unit][+e|n][/yinc[unit][+e|n]]'. x_inc [and optionally y_inc] is the grid spacing.

  • region (str or list) – 'xmin/xmax/ymin/ymax[+r][+uunit]'. Specify the region of interest.

  • outfile (str) – Required if ‘table’ is a file. The file name for the output ASCII file.


output (pandas.DataFrame or None) – Return type depends on whether the outfile parameter is set:

  • pandas.DataFrame table with (x, y, z) columns if outfile is not set

  • None if outfile is set (filtered output will be stored in outfile)