GeoTIFFs to NetCDF

In this example, we demonstrates the workflow for creating a GS file from the GeoTIFF (.tif/.tiff) file format. This includes adding individual TIF files as single 2-D variables, as well as how to create a 3-D variable by stacking multiple TIF files along a specified dimension.

Additionally, this example shows how to handle Raster data that have differing x-y grids. Specifically, this example creates the following Raster datasets:

  1. Raster Dataset #1

    1a. 2-D magnetic grid, original x-y discretization (600 m cell size)

  2. Raster Dataset #2

    2a. 2-D magnetic grid, aligned to match the x-y dimensions of the resistivity layers (1000 m cell size)

    2b. 3-D resistivity grid

Dataset References:

Minsley, B.J., James, S.R., Bedrosian, P.A., Pace, M.D., Hoogenboom, B.E., and Burton, B.L., 2021, Airborne electromagnetic, magnetic, and radiometric survey of the Mississippi Alluvial Plain, November 2019 - March 2020: U.S. Geological Survey data release, https://doi.org/10.5066/P9E44CTQ.

James, S.R., and Minsley, B.J., 2021, Combined results and derivative products of hydrogeologic structure and properties from airborne electromagnetic surveys in the Mississippi Alluvial Plain: U.S. Geological Survey data release, https://doi.org/10.5066/P9382RCI.

import matplotlib.pyplot as plt
from os.path import join
import gspy
from gspy import Survey
from pprint import pprint

Convert data from GeoTIFF to NetCDF

Initialize the Survey

# Path to example files
data_path = "..//..//..//..//example_material//example_2"

# Survey metadata file
metadata = join(data_path, "data//Tempest_survey_md.yml")

# Establish the Survey
survey = Survey.from_dict(metadata)


container = survey.gs.add_container('derived_products', **dict(content = "raw and processed data",
                                                        comment = "This is a test"))

Create the First Raster Dataset Import 2-D magnetic data, discretized on 600 m x 600 m grid Define input metadata file (which contains the TIF filename linked with desired variable name)

d_supp1 = join(data_path, 'data//Tempest_raster_md.yml')

# Read data and format as Raster class object
container.gs.add(key="map", metadata_file=d_supp1)
<xarray.DataTree 'map'>
Group: /survey/derived_products/map
    Dimensions:       (x: 599, nv: 2, y: 1212)
    Coordinates:
      * x             (x) float64 5kB 2.928e+05 2.934e+05 ... 6.51e+05 6.516e+05
      * nv            (nv) int64 16B 0 1
      * y             (y) float64 10kB 1.607e+06 1.606e+06 ... 8.808e+05 8.802e+05
        spatial_ref   float64 8B 0.0
    Data variables:
        x_bnds        (x, nv) float64 10kB 2.925e+05 2.931e+05 ... 6.519e+05
        y_bnds        (y, nv) float64 19kB 1.607e+06 1.606e+06 ... 8.799e+05
        magnetic_tmi  (y, x) float64 6MB nan nan nan nan nan ... nan nan nan nan nan
    Attributes:
        comment:  <additional details or ancillary information>
        content:  gridded magnetic map


Create the Second Raster Dataset

# Import both 3-D resistivity and 2-D magnetic data, aligned onto a common 1000 m x 1000 m grid
# Define input metadata file (which contains the TIF filenames linked with desired variable names)
d_supp2 = join(data_path, 'data//Tempest_rasters_md.yml')

# Read data and format as Raster class object
container.gs.add(key="maps", metadata_file=d_supp2)
<xarray.DataTree 'maps'>
Group: /survey/derived_products/maps
    Dimensions:       (z: 5, nv: 2, x: 363, y: 770)
    Coordinates:
      * z             (z) float64 40B 0.0 5.0 10.0 15.0 20.0
      * nv            (nv) int64 16B 0 1
      * x             (x) float64 3kB 2.915e+05 2.925e+05 ... 6.525e+05 6.535e+05
      * y             (y) float64 6kB 1.648e+06 1.647e+06 ... 8.798e+05 8.788e+05
        spatial_ref   float64 8B 0.0
    Data variables:
        z_bnds        (z, nv) float64 80B -2.5 2.5 2.5 7.5 ... 12.5 17.5 17.5 22.5
        x_bnds        (x, nv) float64 6kB 2.91e+05 2.92e+05 ... 6.53e+05 6.54e+05
        y_bnds        (y, nv) float64 12kB 1.648e+06 1.647e+06 ... 8.783e+05
        resistivity   (z, y, x) float64 11MB nan nan nan nan nan ... nan nan nan nan
        magnetic_tmi  (y, x) float32 1MB nan nan nan nan nan ... nan nan nan nan nan
    Attributes:
        comment:  <additional details or ancillary information>
        content:  interpolated resistivity models (3-D depth grid) and magnetic m...


Save to NetCDF file

d_out = join(data_path, 'data//tifs.nc')
survey.gs.to_netcdf(d_out)

Reading back in the GS NetCDF file

new_survey = gspy.open_datatree(d_out)['survey']

Plotting

# Make a map-view plot of a specific data variable, using Xarray's plotter
# In this case, we slice the 3-D resistivity variable along the depth dimension
new_survey['derived_products']["maps"]['resistivity'].plot(col='z', vmax=3, cmap='jet', robust=True)

# Make a map-view plot comparing the different x-y discretization of the two magnetic variables, using Xarray's plotter
plt.figure()
ax=plt.gca()
new_survey['derived_products']["maps"]['magnetic_tmi'].plot(ax=ax, cmap='jet', robust=True)
new_survey['derived_products']["map"]['magnetic_tmi'].plot(ax=ax, cmap='Greys', cbar_kwargs={'label': ''}, robust=True)
plt.ylim([1.20556e6, 1.21476e6])
plt.xlim([3.5201e5, 3.6396e5])
plt.show()
  • z = 0.0, z = 5.0, z = 10.0, z = 15.0, z = 20.0
  • spatial_ref = 0.0

Total running time of the script: (0 minutes 0.573 seconds)

Gallery generated by Sphinx-Gallery