Grid Derivatives

Demonstrate calculation of various grid derivatives.

  1. TMI Grid
  2. DERIVATIVE_X
  3. DERIVATIVE_Y
  4. DERIVATIVE_Z
  5. DERIVATIVE_XY
  6. DERIVATIVE_XYZ
  7. TILT_ANGLE

TMI Grid

This is Total Magnetic Intensity (TMI) data from the Black Hills Norite in South Australia.

Reference: https://doi.org/10.1071/ASEG2016ab115


In [1]:
import geosoft.gxpy.gx as gx
import geosoft.gxpy.utility as gxu
import geosoft.gxpy.grid as gxgrd
import geosoft.gxpy.grid_utility as gxgrdu

from IPython.display import Image

gxc = gx.GXpy()
gxu.check_version('9.4.0b0')

# get the sample data from github
url = 'https://github.com/GeosoftInc/gxpy/raw/master/examples/data/'
grid = 'bhn_tmi_250m.grd'
gxu.url_retrieve(url + grid)
gxu.url_retrieve(url + grid + '.gi')
gxu.url_retrieve(url + grid + '.xml')

grd = gxgrd.Grid.open(grid)
Image(grd.image_file(shade=True, pix_width=500))


Out[1]:

DERIVATIVE_X


In [2]:
gdx = gxgrdu.derivative(grd, gxgrdu.DERIVATIVE_X)
Image(gdx.image_file(shade=True, pix_width=500))


Out[2]:

DERIVATIVE_Y


In [3]:
gdy = gxgrdu.derivative(grd, gxgrdu.DERIVATIVE_Y)
Image(gdy.image_file(shade=True, pix_width=500))


Out[3]:

DERIVATIVE_Z


In [4]:
gdz = gxgrdu.derivative(grd, gxgrdu.DERIVATIVE_Z)
Image(gdz.image_file(shade=True, pix_width=500))


Out[4]:

Z derivative using space-domain convolution:


In [5]:
gdz = gxgrdu.derivative(grd, gxgrdu.DERIVATIVE_Z, fft=False)
Image(gdz.image_file(shade=True, pix_width=500))


Out[5]:

DERIVATIVE_XY


In [6]:
gdxy = gxgrdu.derivative(grd, gxgrdu.DERIVATIVE_XY)
Image(gdxy.image_file(shade=True, pix_width=500))


Out[6]:

DERIVATIVE_XYZ


In [7]:
gdxyz = gxgrdu.derivative(grd, gxgrdu.DERIVATIVE_XYZ)
Image(gdxyz.image_file(shade=True, pix_width=500))


Out[7]:

TILT_ANGLE


In [8]:
gdt = gxgrdu.derivative(grd, gxgrdu.TILT_ANGLE)
Image(gdt.image_file(shade=True, pix_width=500))


Out[8]: