points_to_raster.py

"""
Creates a raster from a point ShapeFile.
This is used in the campsite analysis to create a raster from a ShapeFile that
is generated by merging the vertices of the campsite polyline vertices and points
from a single corgrid text file.
"""
from typing import Tuple
import os
from subprocess import call, PIPE
from raster import delete_raster
from logger import Logger


def points_to_raster(gdal_grid_path: str, points_shapefile: str, z_field: str, out_raster: str, cell_size: float, buffered_extent: Tuple[float, float, float, float]) -> None:
    """
    :param gdal_grid_path: The path to the GDAL Grid executable
    :param points_raster: The path to the input points ShapeFile
    :param out_raster: The path to the output raster
    :param clip_shape_file: The path to the polygon ShapeFile to use for clipping
    :param where_clause: Feature filter for selecting which features to use for clipping
    https://gdal.org/programs/gdal_grid.html
    """

    log = Logger('Points to Raster')

    assert os.path.isfile(gdal_grid_path), f'Missing GDAL Grid executable at {gdal_grid_path}'
    assert os.path.isfile(points_shapefile), f'Missing point ShapeFile operation input at {points_shapefile}'

    # Make sure the rasters get removed before they get re-made
    delete_raster(out_raster)

    # Reset the where parameter to an empty string if no where clause is provided
    # TODO: This is giving us 64-bit rasters for some reason and a weird nodata value with nan as well. We're probably losing precision somewhere
    x_extent = f'{buffered_extent[0]} {buffered_extent[1]}'
    y_extent = f'{buffered_extent[2]} {buffered_extent[3]}'
    gdal_args = f' -a linear -zfield {z_field} -tr {cell_size} {cell_size} -txe {x_extent} -tye {y_extent} {points_shapefile} {out_raster}'
    log.debug('RUNNING GdalGrid: ' + gdal_grid_path + gdal_args)

    if ' ' in gdal_grid_path:
        gdal_grid_path = f'"{gdal_grid_path}"'

    return_val = call(gdal_grid_path + gdal_args, stdout=PIPE, shell=True)

    assert return_val == 0, f'Error creating raster from points. Input points ShapeFile {points_shapefile} and output raster {out_raster}'