Spatial correlation mapping

LongNguyen031017 · March 20, 2022, 5:30am

Hi everyone,
I would like to ask if there are any possible ways to calculate the spatial correlation in GMT6?
Thanks,

thwbecker · March 20, 2022, 3:28pm

That’s not much information here as to what the objectives are, but I have a GMT -4- code that computes the cross (or auto) correlation on moving caps for two GMT/Netcdf files,

github.com

geodynamics/hc/blob/master/grdgrd2correlation.c

/* 


read in two grid files and compute the correlation of points within a
certain radius around each location

this assumes spherical grids by default, but see switch

grdgrd2correlation: usage:
	grdgrd2correlation file1.grd file2.grd [radius, 500 km] [remove_lin, 0] [only_print_stat, 1] [is_global, 1] [lin_reg_mode, 2]

grdgrd2correlation: output:
	lon lat correlation slope number_of_points diff_from_global


for regional grids, this assumes 0...360 convention


*/
#include "hc_ggrd.h"

This file has been truncated. show original

Check the Makefile for how to compile - no documentation, but should work to first order. Attached are two fields and theircorrt.pdf (153.3 KB) 1000 km correlation.

LongNguyen031017 · March 21, 2022, 12:48am

Hello,
Sorry for not posting a clear description. You’re right, what I want is to compute the autocorrelation between two variables. I think I also learn something from your idea. But I would like to ask which program you use for computing autocorrelation?. It not look like GMT.
Thank you.