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SpatialIntersection

Updated
globalmapper.SpatialIntersection(GM_LayerHandle_t32 aLayer1, GM_LayerHandle_t32 aLayer2, GM_SpatialOps_Params_t aParams) → GM_Error_t32

The Intersection operation creates a new layer consisting of just the overlapping regions (parts of the original features) in the two input layers, layer 1 and layer 2. New features receive attributes from both layers.

Parameters:

  • aLayer1 (GM_LayerHandle_t32) – First layer in operation

  • aLayer2 (GM_LayerHandle_t32) – Second layer in operation

  • aParams (GM_SpatialOps_Params_t) – Parameters

Returns:

Error Code

Return type:

GM_Error_t32


BEFORE

AFTER
../_images/Red_Blue_Circles.png ../_images/IntersectionAfter.png

Example

The following is an example of SpatialIntersection.

import os
import globalmapper as gm

import_dir = "Z:/GM-20069/spatial_operations_sample_data/"
# Close all layers that may be open
layers_are_open = gm.GetLoadedLayerList()
if layers_are_open:
    arr_ptr, arr_size = layers_are_open
    initial_layers = gm.GM_LayerHandle_array_frompointer(arr_ptr)
    for i in range(arr_size):
        gm.CloseLayer(initial_layers[i])

err_LoadLayerList1, array_pointer, array_size_param = gm.LoadLayerList(
    os.path.join(import_dir, "LeftBlueCircle.shp"),
    gm.GM_LoadFlags_HideAllPrompts,
)
err_LoadLayerList2, array_pointer, array_size_param = gm.LoadLayerList(
    os.path.join(import_dir, "RightRedCircle.shp"),
    gm.GM_LoadFlags_HideAllPrompts,
)

# Get handle for the loaded layers
arr_ptr, arr_size = gm.GetLoadedLayerList()
layers_array = gm.GM_LayerHandle_array_frompointer(arr_ptr)
layers_list = gm.carray_to_list(layers_array, arr_size)

### START SAMPLE
spatial_params = gm.GM_SpatialOps_Params_t()
spatial_params.mResultLayerName = "Intersection_Result"
err_SpatialIntersection = gm.SpatialIntersection(
    layers_list[0], layers_list[1], spatial_params
)

### END SAMPLE

assert (
    gm.GM_Error_None == err_LoadLayerList1
), f"LoadLayerList1: Expected {gm.GM_Error_None}, got {err_LoadLayerList1}"
assert (
    gm.GM_Error_None == err_LoadLayerList2
), f"LoadLayerList2: Expected {gm.GM_Error_None}, got {err_LoadLayerList2}"
assert (
    gm.GM_Error_None == err_SpatialIntersection
), f"SpatialIntersection: Expected {gm.GM_Error_None}, got {err_SpatialIntersection}"

assert os.path.isdir(import_dir), f"Import directory doesn't exist: {import_dir}"
assert os.path.exists(
    os.path.join(import_dir, "LeftBlueCircle.shp")
), "Sample data doesn't exist"
assert os.path.exists(
    os.path.join(import_dir, "RightRedCircle.shp")
), "Sample data doesn't exist"

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