Create and Inspect a RegionMask¶

RegionMasks can be created using shapefiles, geometry objects or an extent objects in combination with a Boolean Numpy array, as shown below.

Import Libraries and Modules¶

In [1]:

import pathlib
import numpy as np
import matplotlib.pyplot as plt
import geokit.core.srs
import geokit.core.regionmask
import geokit.core.geom
import geokit.core.extent
from geokit.core.get_test_data import get_test_data

import pathlib import numpy as np import matplotlib.pyplot as plt import geokit.core.srs import geokit.core.regionmask import geokit.core.geom import geokit.core.extent from geokit.core.get_test_data import get_test_data

Create RegionMask From Shapefile¶

In [2]:

# Define a region-centered CRS (Aachen)
aachen_centered_srs = geokit.core.srs.centeredLAEA(6.083, 50.775)

# Load RegionMask from example shapefile
aachen_region_mask = geokit.core.regionmask.RegionMask.load(
    get_test_data(file_name="aachenShapefile.shp"),
    pixelRes=20,
    srs=aachen_centered_srs,
)

ax_handle_aachen = aachen_region_mask.drawSelf(figsize=(6, 6))

# Define a region-centered CRS (Aachen) aachen_centered_srs = geokit.core.srs.centeredLAEA(6.083, 50.775) # Load RegionMask from example shapefile aachen_region_mask = geokit.core.regionmask.RegionMask.load( get_test_data(file_name="aachenShapefile.shp"), pixelRes=20, srs=aachen_centered_srs, ) ax_handle_aachen = aachen_region_mask.drawSelf(figsize=(6, 6))

Create RegioMask from Geometry¶

In this example, a box is used, but a RegionMask can be created from any geometry object.

In [3]:

# boundary box tuple with (xmin, ymin, xmax, ymax)
srs_scale = 10**6
boundary_box_tuple = (4.035 * srs_scale, 3.07 * srs_scale, 4.07 * srs_scale, 3.105 * srs_scale)
box_upper_aachen = geokit.core.geom.box(boundary_box_tuple, srs=3035)

upper_aachen_box_region_mask = geokit.core.regionmask.RegionMask.load(
    box_upper_aachen,
    srs=3035,
    pixelRes=20,
)

ax_handle_aachen_box = upper_aachen_box_region_mask.drawSelf(figsize=(6, 6))

# boundary box tuple with (xmin, ymin, xmax, ymax) srs_scale = 10**6 boundary_box_tuple = (4.035 * srs_scale, 3.07 * srs_scale, 4.07 * srs_scale, 3.105 * srs_scale) box_upper_aachen = geokit.core.geom.box(boundary_box_tuple, srs=3035) upper_aachen_box_region_mask = geokit.core.regionmask.RegionMask.load( box_upper_aachen, srs=3035, pixelRes=20, ) ax_handle_aachen_box = upper_aachen_box_region_mask.drawSelf(figsize=(6, 6))

From Extent and Boolean Numpy Array¶

This method of creating a RegionMask is useful when the region of interest for your analysis is a Boolean raster. Specify the extent of the raster and provide the regions to be included with a value of 1 and those to be excluded with a value of 0 in the NumPy array.

In [4]:

srs_scale = 10**6
boundary_box_tuple = (4.035 * srs_scale, 3.07 * srs_scale, 4.07 * srs_scale, 3.105 * srs_scale)
extent = geokit.core.extent.Extent(boundary_box_tuple, srs=3035)
example_data = np.random.randint(2, size=(20, 25), dtype=bool)

np.random.seed(0)
# example_data = np.random.rand(20,25).astype(bool)
region_mask_from_random_mask = geokit.core.regionmask.RegionMask.fromMask(
    extent=extent,
    mask=example_data,
)

fig, axs = plt.subplots(ncols=2, figsize=(12, 6))
region_mask_from_random_mask_handle = region_mask_from_random_mask.drawSelf(ax=axs[0])
ax_handle_numpy_array = geokit.drawImage(example_data, ax=axs[1])

srs_scale = 10**6 boundary_box_tuple = (4.035 * srs_scale, 3.07 * srs_scale, 4.07 * srs_scale, 3.105 * srs_scale) extent = geokit.core.extent.Extent(boundary_box_tuple, srs=3035) example_data = np.random.randint(2, size=(20, 25), dtype=bool) np.random.seed(0) # example_data = np.random.rand(20,25).astype(bool) region_mask_from_random_mask = geokit.core.regionmask.RegionMask.fromMask( extent=extent, mask=example_data, ) fig, axs = plt.subplots(ncols=2, figsize=(12, 6)) region_mask_from_random_mask_handle = region_mask_from_random_mask.drawSelf(ax=axs[0]) ax_handle_numpy_array = geokit.drawImage(example_data, ax=axs[1])

Create a RegionMask from Geometry¶

In [5]:

## Display the RegionMask
aachen_region_mask

## Display the RegionMask aachen_region_mask

Out[5]:

In [6]:

## Display basic info
print("Extent:", aachen_region_mask.extent)
print("Pixel size:", aachen_region_mask.pixelWidth, aachen_region_mask.pixelHeight)
print("Area (m²):", aachen_region_mask.area)

## Display basic info print("Extent:", aachen_region_mask.extent) print("Pixel size:", aachen_region_mask.pixelWidth, aachen_region_mask.pixelHeight) print("Area (m²):", aachen_region_mask.area)

Extent: (-7640.00000,-31220.00000,23820.00000,19500.00000)
Pixel size: 20 20
Area (m²): 709403600