Coverage for stems/gis/convert.py : 92%

""" GIS variable conversion library 

Functions here are convenient ways of going from various representations 

of GIS information used in this stack (e.g., WKT) to the following 

representations: 

* Coordinate Reference System 

* :py:class:`rasterio.crs.CRS` 

* Geotransform 

* :py:class:`affine.Affine` 

* Bounding Box 

* :py:class:`rasterio.coords.BoundingBox` 

* Bounds 

* :py:class:`shapely.geom.Polygon` 

""" 

from functools import singledispatch 

import logging 

from affine import Affine 

import numpy as np 

from osgeo import osr 

from rasterio.coords import BoundingBox 

from rasterio.crs import CRS 

from rasterio.errors import CRSError 

import shapely.geometry 

from ..utils import (find_subclasses, 

register_multi_singledispatch) 

logger = logging.getLogger() 

LIST_TYPE = (tuple, list, np.ndarray, ) 

# XARRAY_TYPE = (xr.Dataset, xr.DataArray) 

GEOM_TYPE = find_subclasses(shapely.geometry.base.BaseGeometry) 

# ============================================================================ 

# Affine geotransform 

@singledispatch 

def to_transform(value, from_gdal=False): 

""" Convert input into an :py:class:`affine.Affine` transform 

Parameters 

---------- 

value : Affine or iterable 

6 numbers representing affine transform 

from_gdal : bool, optional 

If `value` is a tuple or list, specifies if transform 

is GDAL variety (True) or rasterio/affine (False) 

Returns 

------- 

affine.Affine 

Affine transform 

""" 

raise _CANT_CONVERT(value) 

@to_transform.register(Affine) 

def _to_transform_affine(value, from_gdal=False): 

return value 

@register_multi_singledispatch(to_transform, LIST_TYPE) 

def _to_transform_iter(value, from_gdal=False): 

if from_gdal: 

return Affine.from_gdal(*value[:6]) 

else: 

return Affine(*value[:6]) 

@to_transform.register(str) 

def _to_transform_str(value, from_gdal=False, sep=','): 

return _to_transform_iter([float(v) for v in value.split(sep)]) 

# ============================================================================ 

# CRS 

# TODO: Dispatch function for Cartopy 

@singledispatch 

def to_crs(value): 

""" Convert a CRS representation to a :py:class:`rasterio.crs.CRS` 

Parameters 

---------- 

value : str, int, dict, or osr.SpatialReference 

Coordinate reference system as WKT, Proj.4 string, EPSG code, 

rasterio-compatible proj4 attributes in a dict, or OSR definition 

Returns 

------- 

rasterio.crs.CRS 

CRS 

""" 

raise _CANT_CONVERT(value) 

@to_crs.register(CRS) 

def _to_crs_crs(value): 

return value 

@to_crs.register(str) 

def _to_crs_str(value): 

# After rasterio=1.0.14 WKT is backbone so try it first 

try: 

crs_ = CRS.from_wkt(value) 

crs_.is_valid 

except CRSError as err: 

logger.debug('Could not parse CRS as WKT', err) 

try: 

crs_ = CRS.from_string(value) 

crs_.is_valid 

except CRSError as err: 

logger.debug('Could not parse CRS as Proj4', err) 

raise CRSError('Could not interpret CRS input as ' 

'either WKT or Proj4') 

return crs_ 

@to_crs.register(int) 

def _to_crs_epsg(value): 

return CRS.from_epsg(value) 

@to_crs.register(dict) 

def _to_crs_dict(value): 

return CRS(value) 

@to_crs.register(osr.SpatialReference) 

def _to_crs_osr(value): 

return CRS.from_wkt(value.ExportToWkt()) 

# ============================================================================ 

# BoundingBox 

@singledispatch 

def to_bounds(value): 

""" Convert input to a :py:class:`rasterio.coords.BoundingBox` 

Parameters 

---------- 

value : iterable, or Polygon 

Input containing some geographic information 

Returns 

------- 

BoundingBox 

Bounding box (left, bottom, right, top). Also described as 

(minx, miny, maxx, maxy) 

""" 

raise _CANT_CONVERT(value) 

@to_bounds.register(BoundingBox) 

def _to_bounds_bounds(value): 

return value 

@register_multi_singledispatch(to_bounds, LIST_TYPE) 

def _to_bounds_iter(value): 

return BoundingBox(*value) 

@register_multi_singledispatch(to_bounds, GEOM_TYPE) 

def _to_bounds_geom(value): 

return BoundingBox(*value.bounds) 

# ============================================================================ 

# Polygon 

@singledispatch 

def to_bbox(value): 

""" Convert input a bounding box :py:class:`shapely.geometry.Polygon` 

Parameters 

---------- 

value : BoundingBox 

Object representing a bounding box, or an xarray object with coords 

we can use to calculate one from 

Returns 

------- 

shapely.geometry.Polygon 

BoundingBox as a polygon 

""" 

raise _CANT_CONVERT(value) 

@register_multi_singledispatch(to_bbox, GEOM_TYPE) 

def _to_bbox_geom(value): 

return _to_bbox_bounds(BoundingBox(*value.bounds)) 

@to_bbox.register(BoundingBox) 

def _to_bbox_bounds(value): 

return shapely.geometry.box(*value) 

# ============================================================================ 

# UTILITIES 

def _CANT_CONVERT(obj): 

return TypeError(f"Don't know how to convert this type: {type(obj)}")