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73 lines
2.3 KiB
Markdown
73 lines
2.3 KiB
Markdown
# Central Coast aerial lidar processing
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Python scripts for cleaning, classifying, and extracting survey profiles from las point clouds.
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### 1. Enter input parameters
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Input parameters are entered into excel spreadsheets, e.g. `param-files/survey-1.xlsx`. The python scripts take their input in yaml format. The spreadsheets can be converted to yaml by running:
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```
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python excel_to_yaml.py
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```
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### 2. Manipulate las data
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`las_manipulation.py` does the following to the input las file:
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- clip to beach extent
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- classify ground points (so vegetation and buildings can be removed later)
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- draw a polygon to remove swash zone interference
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Example usage:
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```
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# Process single survey at specific beach
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python las_manipulation.py param-files/survey-1-avoca.yaml
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# Process single survey at multiple beaches
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python las_manipulation.py param-files/survey-1-avoca.yaml param-files/survey-1-pearl.yaml
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# Process all surveys at specific beach
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python las_manipulation.py param-files/*avoca.yaml
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# Process all beaches for specific survey date
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python las_manipulation.py param-files/survey-1*.yaml
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```
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### 3. Check swash clipping mask
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The swash clipping mask should be checked visually to ensure it is correct.
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### 4. Export results
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`las_outputs.py` does the following, based on the outputs of `las_manipulation.py`:
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- remove swash zone
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- extract elevations from point cloud at profile locations
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- complete volume analysis based on Nielsen et al. (1992)
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- save figures of profile cross sections
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- save raster of ground surface
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Example usage:
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```
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python las_outputs.py param-files/survey-1-avoca.yaml
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```
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### 5. Generate erosion heatmaps
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`generate_heatmaps.py` creates a heatmap raster by calculating the elevation difference between the current and previous surveys.
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`generate_heatmaps.py` relies on `arcpy`, so this script must be run using the version of `python` that was installed with ArcGIS.
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Example usage:
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```
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C:/Python27/ArcGIS10.4/python generate_heatmaps.py param-files/survey-1-avoca.yaml
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```
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### 6. Export erosion heatmaps
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`plot_heatmaps.py` exports a jpg erosion heatmap at all of the beaches covered by the specified heatmap tif.
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`plot_heatmaps.py` relies on `arcpy`, so this script must be run using the version of `python` that was installed with ArcGIS.
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Example usage:
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```
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C:/Python27/ArcGIS10.4/python plot_heatmaps.py param-files/survey-1-avoca.yaml
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```
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