# Source code for climada.util.lines_polys_handler

```
"""
This file is part of CLIMADA.
Copyright (C) 2017 ETH Zurich, CLIMADA contributors listed in AUTHORS.
CLIMADA is free software: you can redistribute it and/or modify it under the
terms of the GNU Lesser General Public License as published by the Free
Software Foundation, version 3.
CLIMADA is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with CLIMADA. If not, see <https://www.gnu.org/licenses/>.
"""
import logging
import copy
from enum import Enum
import cartopy.crs as ccrs
import geopandas as gpd
import numpy as np
import pandas as pd
import pyproj
import scipy as sp
import shapely as sh
import shapely.geometry as shgeom
from climada.engine import ImpactCalc
from climada.util import coordinates as u_coord
LOGGER = logging.getLogger(__name__)
[docs]class DisaggMethod(Enum):
"""
Disaggregation Method for the ... function
DIV : the geometry's distributed to equal parts over all its interpolated points
FIX : the geometry's value is replicated over all its interpolated points
"""
DIV = 'div'
FIX = 'fix'
[docs]class AggMethod(Enum):
"""
Aggregation Method for the aggregate_impact_mat function
SUM : the impact is summed over all points in the polygon/line
"""
SUM = 'sum'
[docs]def calc_geom_impact(
exp, impf_set, haz, res, to_meters=False, disagg_met=DisaggMethod.DIV,
disagg_val=None, agg_met=AggMethod.SUM):
"""
Compute impact for exposure with (multi-)polygons and/or (multi-)lines.
Lat/Lon values in exp.gdf are ignored, only exp.gdf.geometry is considered.
The geometries are first disaggregated to points. Polygons: grid with
resolution res*res. Lines: points along the line separated by distance res.
The impact per point is then re-aggregated for each geometry.
Parameters
----------
exp : Exposures
The exposure instance with exp.gdf.geometry containing (multi-)polygons
and/or (multi-)lines
impf_set : ImpactFuncSet
The set of impact functions.
haz : Hazard
The hazard instance.
res : float
Resolution of the disaggregation grid (polygon) or line (lines).
to_meters : bool, optional
If True, res is interpreted as meters, and geometries are projected to
an equal area projection for disaggregation. The exposures are
then projected back to the original projections before impact
calculation. The default is False.
disagg_met : DisaggMethod
Disaggregation method of the shapes's original value onto its inter-
polated points. 'DIV': Divide the value evenly over all the new points;
'FIX': Replicate the value onto all the new points. Default is 'DIV'.
Works in combination with the kwarg 'disagg_val'.
disagg_val: float, optional
Specifies what number should be taken as the value, which
is to be disaggregated according to the method provided in disagg_met.
None: The shape's value is taken from the exp.gdf.value column.
float: This given number will be disaggregated according to the method.
In case exp.gdf.value column exists, original values in there will be
ignored.
The default is None.
agg_met : AggMethod
Aggregation method of the point impacts into impact for respective
parent-geometry.
If 'SUM', the impact is summed over all points in each geometry.
The default is 'SUM'.
Returns
-------
Impact
Impact object with the impact per geometry (rows of exp.gdf). Contains
two additional attributes 'geom_exp' and 'coord_exp', the first one
being the origninal line or polygon geometries for which impact was
computed.
See Also
--------
exp_geom_to_pnt: disaggregate exposures
"""
# disaggregate exposure
exp_pnt = exp_geom_to_pnt(
exp=exp, res=res,
to_meters=to_meters, disagg_met=disagg_met,
disagg_val=disagg_val
)
exp_pnt.assign_centroids(haz)
# compute point impact
calc = ImpactCalc(exp_pnt, impf_set, haz)
impact_pnt = calc.impact(save_mat=True, assign_centroids=False)
# re-aggregate impact to original exposure geometry
impact_agg = impact_pnt_agg(impact_pnt, exp_pnt.gdf, agg_met)
return impact_agg
[docs]def impact_pnt_agg(impact_pnt, exp_pnt_gdf, agg_met):
"""
Aggregate the impact per geometry.
The output Impact object contains an extra attribute 'geom_exp'
containing the geometries.
Parameters
----------
impact_pnt : Impact
Impact object with impact per exposure point (lines of exp_pnt)
exp_pnt_gdf : gpd.GeoDataFrame
Geodataframe of an exposures featuring a multi-index. First level indicating
membership of original geometries, second level the disaggregated points.
The exposure is obtained for instance with the disaggregation method
exp_geom_to_pnt().
agg_met : AggMethod
Aggregation method of the point impacts into impact for respective
parent-geometry.
If 'SUM', the impact is summed over all points in each geometry.
The default is 'SUM'.
Returns
-------
impact_agg : Impact
Impact object with the impact per original geometry. Original geometry
additionally stored in attribute 'geom_exp'; coord_exp contains only
representative points (lat/lon) of those geometries.
See also
--------
exp_geom_to_pnt: exposures disaggregation method
"""
# aggregate impact
mat_agg = _aggregate_impact_mat(impact_pnt, exp_pnt_gdf, agg_met)
# write to impact obj
impact_agg = set_imp_mat(impact_pnt, mat_agg)
# add exposure representation points as coordinates
repr_pnts = gpd.GeoSeries(
exp_pnt_gdf['geometry_orig'][:,0].apply(
lambda x: x.representative_point()))
impact_agg.coord_exp = np.array([repr_pnts.y, repr_pnts.x]).transpose()
# Add original geometries for plotting
impact_agg.geom_exp = exp_pnt_gdf.xs(0, level=1)\
.set_geometry('geometry_orig')\
.geometry.rename('geometry')
return impact_agg
def _aggregate_impact_mat(imp_pnt, gdf_pnt, agg_met):
"""
Aggregate point impact matrix given the geodataframe of disaggregated
geometries.
Parameters
----------
imp_pnt : Impact
Impact object with impact per point (rows of gdf_pnt)
gdf_pnt : gpd.GeoDataFrame
Exposures geodataframe with a multi-index, as obtained from disaggregation
method exp_geom_to_pnt(). First level indicating
membership of original geometries, second level the disaggregated points
agg_met : AggMethod
Aggregation method of the point impacts into impact for respective
parent-geometry.
If 'SUM', the impact is summed over all points in each geometry.
The default is 'SUM'.
Returns
-------
sparse.csr_matrix
matrix of shape #events x #original geometries with impacts.
"""
col_geom = gdf_pnt.index.get_level_values(level=0)
# Converts string multi-index level 0 to integer index
col_geom = np.sort(np.unique(col_geom, return_inverse=True)[1])
row_pnt = np.arange(len(col_geom))
if agg_met is AggMethod.SUM:
mask = np.ones(len(col_geom))
else:
raise NotImplementedError(
f'The available aggregation methods are {AggMethod._member_names_}') # pylint: disable=no-member, protected-access
csr_mask = sp.sparse.csr_matrix(
(mask, (row_pnt, col_geom)),
shape=(len(row_pnt), len(np.unique(col_geom)))
)
return imp_pnt.imp_mat.dot(csr_mask)
[docs]def calc_grid_impact(
exp, impf_set, haz, grid, disagg_met=DisaggMethod.DIV, disagg_val=None,
agg_met=AggMethod.SUM):
"""
Compute impact for exposure with (multi-)polygons and/or (multi-)lines.
Lat/Lon values in exp.gdf are ignored, only exp.gdf.geometry is considered.
The geometries are first disaggregated to points. Polygons: grid with
resolution res*res. Lines: points along the line separated by distance res.
The impact per point is then re-aggregated for each geometry.
Parameters
----------
exp : Exposures
The exposure instance with exp.gdf.geometry containing (multi-)polygons
and/or (multi-)lines
impf_set : ImpactFuncSet
The set of impact functions.
haz : Hazard
The hazard instance.
grid : np.array()
Grid on which to disaggregate the exposures. Provided as two
vectors [x_grid, y_grid].
disagg_met : DisaggMethod
Disaggregation method of the shapes's original value onto its inter-
polated points. 'DIV': Divide the value evenly over all the new points;
'FIX': Replicate the value onto all the new points. Default is 'DIV'.
Works in combination with the kwarg 'disagg_val'.
disagg_val: float, optional
Specifies what number should be taken as the value, which
is to be disaggregated according to the method provided in disagg_met.
None: The shape's value is taken from the exp.gdf.value column.
float: This given number will be disaggregated according to the method.
In case exp.gdf.value column exists, original values in there will be
ignored
The default is None.
agg_met : AggMethod
Aggregation method of the point impacts into impact for respective
parent-geometry.
If 'SUM', the impact is summed over all points in each geometry.
The default is 'SUM'.
Returns
-------
Impact
Impact object with the impact per geometry (rows of exp.gdf). Contains
two additional attributes 'geom_exp' and 'coord_exp', the first one
being the origninal line or polygon geometries for which impact was
computed.
See Also
--------
exp_geom_to_pnt: disaggregate exposures
"""
# disaggregate exposure
exp_pnt = exp_geom_to_grid(
exp=exp, grid= grid, disagg_met=disagg_met,
disagg_val=disagg_val
)
exp_pnt.assign_centroids(haz)
# compute point impact
impact_pnt = ImpactCalc(exp_pnt, impf_set, haz).impact(save_mat=True, assign_centroids=False)
# re-aggregate impact to original exposure geometry
impact_agg = impact_pnt_agg(impact_pnt, exp_pnt.gdf, agg_met)
return impact_agg
[docs]def plot_eai_exp_geom(imp_geom, centered=False, figsize=(9, 13), **kwargs):
"""
Plot the average impact per exposure polygon.
Parameters
----------
imp_geom : Impact
Impact instance with imp_geom set (i.e. computed from exposures with
polygons)
centered : bool, optional
Center the plot. The default is False.
figsize : (float, float), optional
Figure size. The default is (9, 13).
**kwargs : dict
Keyword arguments for GeoDataFrame.plot()
Returns
-------
ax:
matplotlib axes instance
"""
kwargs['figsize'] = figsize
if 'legend_kwds' not in kwargs:
kwargs['legend_kwds'] = {
'label': f"Impact [{imp_geom.unit}]",
'orientation': "horizontal"
}
if 'legend' not in kwargs:
kwargs['legend'] = True
gdf_plot = gpd.GeoDataFrame(imp_geom.geom_exp)
gdf_plot['impact'] = imp_geom.eai_exp
if centered:
# pylint: disable=abstract-class-instantiated
xmin, xmax = u_coord.lon_bounds(imp_geom.coord_exp[:,1])
proj_plot = ccrs.PlateCarree(central_longitude=0.5 * (xmin + xmax))
gdf_plot = gdf_plot.to_crs(proj_plot)
return gdf_plot.plot(column = 'impact', **kwargs)
[docs]def exp_geom_to_pnt(exp, res, to_meters, disagg_met, disagg_val):
"""
Disaggregate exposures with (multi-)polygons and/or (multi-)lines
geometries to points based on a given resolution.
Parameters
----------
exp : Exposures
The exposure instance with exp.gdf.geometry containing lines or polygons
res : float
Resolution of the disaggregation grid / distance. Can also be a
tuple of [x_grid, y_grid] numpy arrays. In this case, to_meters is
ignored. This is only possible for Polygon-only exposures.
to_meters : bool
If True, res is interpreted as meters, and geometries are projected to
an equal area projection for disaggregation. The exposures are
then projected back to the original projections before impact
calculation. The default is False.
disagg_met : DisaggMethod
Disaggregation method of the shapes's original value onto its inter-
polated points. 'DIV': Divide the value evenly over all the new points;
'FIX': Replicate the value onto all the new points. Default is 'DIV'.
Works in combination with the kwarg 'disagg_val'.
disagg_val: float, optional
Specifies what number should be taken as the value, which
is to be disaggregated according to the method provided in disagg_met.
None: The shape's value is taken from the exp.gdf.value column.
float: This given number will be disaggregated according to the method.
In case exp.gdf.value column exists, original values in there will be
ignored
The default is None.
Returns
-------
exp_pnt : Exposures
Exposures with a double index geodataframe, first level indicating
membership of the original geometries of exp,
second for the point disaggregation within each geometries.
"""
if disagg_val is not None:
exp = exp.copy()
exp.gdf['value'] = disagg_val
if ((disagg_val is None) and ('value' not in exp.gdf.columns)):
raise ValueError('There is no value column in the exposure gdf to'+
' disaggregate from. Please set disagg_val explicitly.')
gdf_pnt = gdf_to_pnts(exp.gdf, res, to_meters)
# disaggregate value column
if disagg_met is DisaggMethod.DIV:
gdf_pnt = _disagg_values_div(gdf_pnt)
# set lat lon and centroids
exp_pnt = exp.copy(deep=False)
exp_pnt.set_gdf(gdf_pnt)
exp_pnt.set_lat_lon()
return exp_pnt
[docs]def exp_geom_to_grid(exp, grid, disagg_met, disagg_val):
"""
Disaggregate exposures with (multi-)polygon geometries to points based on
a pre-defined grid.
Parameters
----------
exp : Exposures
The exposure instance with exp.gdf.geometry containing polygons
grid : np.array()
Grid on which to disaggregate the exposures. Provided as two
vectors [x_grid, y_grid].
disagg_met : DisaggMethod
Disaggregation method of the shapes's original value onto its inter-
polated points. 'DIV': Divide the value evenly over all the new points;
'FIX': Replicate the value onto all the new points. Default is 'DIV'.
Works in combination with the kwarg 'disagg_val'.
disagg_val: float, optional
Specifies what number should be taken as the value, which
is to be disaggregated according to the method provided in disagg_met.
None: The shape's value is taken from the exp.gdf.value column.
float: This given number will be disaggregated according to the method.
In case exp.gdf.value column exists, original values in there will be
ignored
The default is None.
Returns
-------
exp_pnt : Exposures
Exposures with a double index geodataframe, first level indicating
membership of the original geometries of exp,
second for the point disaggregation within each geometries.
Note
----
Works with polygon geometries only. No points or lines are allowed.
"""
if disagg_val is not None:
exp = exp.copy()
exp.gdf.value = disagg_val
if ((disagg_val is None) and ('value' not in exp.gdf.columns)):
raise ValueError('There is no value column in the exposure gdf to'+
' disaggregate from. Please set disagg_val explicitly.')
gdf_pnt = gdf_to_grid(exp.gdf, grid)
# disaggregate value column
if disagg_met is DisaggMethod.DIV:
gdf_pnt = _disagg_values_div(gdf_pnt)
# set lat lon and centroids
exp_pnt = exp.copy(deep=False)
exp_pnt.set_gdf(gdf_pnt)
exp_pnt.set_lat_lon()
return exp_pnt
def _pnt_line_poly_mask(gdf):
"""
Mask for points, lines and polygons
Parameters
----------
gdf : gpd.GeoDataFrame
Feodataframe instance with gdf.geometry containing (multi)-lines or
(multi-)polygons. Points are ignored.
Returns
-------
pnt_mask, line_mask, poly_mask :
"""
pnt_mask = gdf.geometry.apply(lambda x: isinstance(x, shgeom.Point))
line_mask = gdf.geometry.apply(lambda x: isinstance(x, shgeom.LineString))
line_mask |= gdf.geometry.apply(lambda x: isinstance(x, shgeom.MultiLineString))
poly_mask = gdf.geometry.apply(lambda x: isinstance(x, shgeom.Polygon))
poly_mask |= gdf.geometry.apply(lambda x: isinstance(x, shgeom.MultiPolygon))
return pnt_mask, line_mask, poly_mask
[docs]def gdf_to_pnts(gdf, res, to_meters):
"""
Disaggregate geodataframe with (multi-)polygons geometries to points.
Parameters
----------
gdf : gpd.GeoDataFrame
Feodataframe instance with gdf.geometry containing (multi)-lines or
(multi-)polygons.
Points are ignored.
res : float
Resolution of the disaggregation grid. Can also be a tuple of
[x_grid, y_grid] numpy
arrays. In this case, to_meters is ignored.
to_meters : bool
If True, the geometries are projected to an equal area projection before
the disaggregation. res is then in meters. The exposures are then
reprojected into the original projections before the impact calculation.
Returns
-------
gdf_pnt : gpd.GeoDataFrame
with a double index, first for the geometries of exp, second for the
point disaggregation of the geometries.
"""
if gdf.empty:
return gdf
pnt_mask, line_mask, poly_mask = _pnt_line_poly_mask(gdf)
# Concatenating an empty dataframe with an index together with
# a dataframe with a multi-index breaks the multi-index
gdf_pnt = gpd.GeoDataFrame([])
if pnt_mask.any():
gdf_pnt_only = gdf[pnt_mask]
gdf_pnt_only['geometry_orig'] = gdf_pnt_only['geometry'].copy()
index = gdf_pnt_only.index.values
gdf_pnt_only.index = pd.MultiIndex.from_arrays([index, np.zeros(len(index))])
gdf_pnt = gpd.GeoDataFrame(pd.concat([
gdf_pnt,
gdf_pnt_only
]))
if line_mask.any():
gdf_pnt = gpd.GeoDataFrame(pd.concat([
gdf_pnt,
_line_to_pnts(gdf[line_mask], res, to_meters)
]))
if poly_mask.any():
gdf_pnt = gpd.GeoDataFrame(pd.concat([
gdf_pnt,
_poly_to_pnts(gdf[poly_mask], res, to_meters)
]))
return gdf_pnt
[docs]def gdf_to_grid(gdf, grid):
"""
Disaggregate geodataframe with (multi-)polygons geometries to points based
on a pre-defined grid.
Parameters
----------
gdf : gpd.GeoDataFrame
Geodataframe instance with gdf.geometry containing (multi-)polygons.
grid : np.array()
Grid on which to disaggregate the exposures. Provided as two vectors
[x_grid, y_grid].
Returns
-------
gdf_pnt : gpd.GeoDataFrame
with a double index, first for the geometries of exp, second for the
point disaggregation of the geometries.
Note
----
Works only with polygon geometries. No mixed inputs (with lines or points)
are allowed
Raises
------
AttributeError : if other geometry types than polygons are contained in the
dataframe
"""
if gdf.empty:
return gdf
pnt_mask, line_mask, poly_mask = _pnt_line_poly_mask(gdf)
# Concatenating an empty dataframe with an index together with
# a dataframe with a multi-index breaks the multi-index
if (line_mask.any() or pnt_mask.any()):
raise AttributeError("The dataframe contains lines and/or polygons."
"Currently only polygon dataframes can be "
"disaggregated onto a fixed grid.")
if poly_mask.any():
return _poly_to_grid(gdf[poly_mask], grid)
return gpd.GeoDataFrame([])
def _disagg_values_div(gdf_pnts):
"""
Disaggregate value column of original gdf to disaggregated point gdf by
dividing value from geometry equally on points.
Parameters
----------
gdf_pnts : gpd.GeoDataFrame
Geodataframe with a double index, first for geometries (lines, polygons),
second for the point disaggregation of the polygons. The value column is assumed
to represent values per polygon / line (first index).
Returns
-------
gdf_disagg : gpd.GeoDataFrame
The value per geometry are evenly distributed over the points per geometry.
"""
gdf_disagg = gdf_pnts.copy(deep=False)
group = gdf_pnts.groupby(axis=0, level=0)
vals = group.value.mean() / group.value.count()
vals = vals.reindex(gdf_pnts.index, level=0)
gdf_disagg['value'] = vals
return gdf_disagg
def _poly_to_pnts(gdf, res, to_meters):
"""
Disaggregate (multi-)polygons geodataframe to points.
Note: If polygon is smaller than specified resolution, a representative
point within the polygon will be chosen, nevertheless. This may lead to
inaccuracies during value assignments / disaggregations.
Parameters
----------
gdf : gpd.GeoDataFrame
Can have any CRS
res : float
Resolution (same units as gdf crs)
to_meters : bool
If True, res is interpreted as meters, and geometries are projected to
an equal area projection for disaggregation.
Returns
-------
gpd.GeoDataFrame
Geodataframe with a double index, first for polygon geometries,
second for the point disaggregation of the polygons.
"""
if gdf.empty:
return gdf
# Needed because gdf.explode(index_parts=True) requires numeric index
idx = gdf.index.to_list() #To restore the naming of the index
gdf_points = gdf.copy().reset_index(drop=True)
# Check if we need to reproject
if to_meters and not gdf.geometry.crs.is_projected:
gdf_points['geometry_pnt'] = gdf_points.apply(
lambda row: _interp_one_poly_m(row.geometry, res, gdf.crs), axis=1)
else:
gdf_points['geometry_pnt'] = gdf_points.apply(
lambda row: _interp_one_poly(row.geometry, res), axis=1)
gdf_points = _swap_geom_cols(
gdf_points, geom_to='geometry_orig', new_geom='geometry_pnt')
gdf_points = gdf_points.explode(index_parts=True)
gdf_points.index = gdf_points.index.set_levels(idx, level=0)
return gdf_points
def _poly_to_grid(gdf, grid):
"""
Disaggregate (multi-)polygons geodataframe to points.
Note: If polygon is smaller than specified resolution, a representative
point within the polygon will be chosen, nevertheless. This may lead to
inaccuracies during value assignments / disaggregations.
Parameters
----------
gdf : gpd.GeoDataFrame
Can have any CRS
grid : np.array()
Grid on which to disaggregate the exposures. Provided as two
vectors [x_grid, y_grid].
Returns
-------
gpd.GeoDataFrame
Geodataframe with a double index, first for polygon geometries,
second for the point disaggregation of the polygons.
"""
if gdf.empty:
return gdf
# Needed because gdf.explode(index_parts=True) requires numeric index
idx = gdf.index.to_list() #To restore the naming of the index
gdf_points = gdf.copy().reset_index(drop=True)
x_grid, y_grid = grid
gdf_points['geometry_pnt'] = gdf_points.apply(
lambda row: _interp_one_poly_grid(row.geometry, x_grid, y_grid), axis=1)
gdf_points = _swap_geom_cols(
gdf_points, geom_to='geometry_orig', new_geom='geometry_pnt')
gdf_points = gdf_points.explode(index_parts=True)
gdf_points.index = gdf_points.index.set_levels(idx, level=0)
return gdf_points
def _interp_one_poly_grid(poly, x_grid, y_grid):
"""
Disaggregate a single polygon to points on grid (does not have to be a
regular raster)
Parameters
----------
poly : shapely Polygon
Polygon
x_grid : np.array
1D array of x-coordinates of grid points.
y_grid : np.array
1D array of y-coordinates of grid points.
Returns
-------
shapely multipoint
Grid of points inside the polygon
"""
if poly.is_empty:
return shgeom.MultiPoint([])
in_geom = sh.vectorized.contains(poly, x_grid, y_grid)
if sum(in_geom.flatten()) > 1:
return shgeom.MultiPoint(list(zip(x_grid[in_geom], y_grid[in_geom])))
LOGGER.warning('Polygon smaller than resolution. Setting a representative point.')
return shgeom.MultiPoint([poly.representative_point()])
def _interp_one_poly(poly, res):
"""
Disaggregate a single polygon to points
Parameters
----------
poly : shapely Polygon
Polygon
res : float
Resolution (same units as gdf crs)
Returns
-------
shapely multipoint
Grid of points rasterizing the polygon
"""
if poly.is_empty:
return shgeom.MultiPoint([])
height, width, trafo = u_coord.pts_to_raster_meta(poly.bounds, (res, res))
x_grid, y_grid = u_coord.raster_to_meshgrid(trafo, width, height)
in_geom = sh.vectorized.contains(poly, x_grid, y_grid)
if sum(in_geom.flatten()) > 1:
return shgeom.MultiPoint(list(zip(x_grid[in_geom], y_grid[in_geom])))
LOGGER.warning('Polygon smaller than resolution. Setting a representative point.')
return shgeom.MultiPoint([poly.representative_point()])
def _interp_one_poly_m(poly, res, orig_crs):
"""
Disaggregate a single polygon to points for resolution given in meters.
Transforms coordinates into an adequate projected equal-area crs for this.
Parameters
----------
poly : shapely Polygon
Polygon
res : float
Resolution in meters
orig_crs: pyproj.CRS
CRS of the polygon
Returns
-------
shapely multipoint
Grid of points rasterizing the polygon
"""
if poly.is_empty:
return shgeom.MultiPoint([])
m_crs = _get_equalarea_proj(poly)
poly_m = reproject_poly(poly, orig_crs, m_crs)
height, width, trafo = u_coord.pts_to_raster_meta(poly_m.bounds, (res, res))
x_grid, y_grid = u_coord.raster_to_meshgrid(trafo, width, height)
in_geom = sh.vectorized.contains(poly_m, x_grid, y_grid)
if sum(in_geom.flatten()) > 1:
x_poly, y_poly = reproject_grid(
x_grid[in_geom], y_grid[in_geom], m_crs, orig_crs)
return shgeom.MultiPoint(list(zip(x_poly, y_poly)))
LOGGER.warning('Polygon smaller than resolution. Setting a representative point.')
return shgeom.MultiPoint([poly.representative_point()])
def _get_equalarea_proj(poly):
"""
Find an adequate Equal Area Cylindrical projection
using a representative point as lat/lon reference.
https://proj.org/operations/projections/cea.html
"""
repr_pnt = poly.representative_point()
lon_0, lat_0 = repr_pnt.x, repr_pnt.y
return f"+proj=cea +lat_0={lat_0:.6f} +lon_0={lon_0:.6f} +units=m"
def _get_pyproj_trafo(orig_crs, dest_crs):
"""
Get pyproj projection from orig_crs to dest_crs
"""
return pyproj.Transformer.from_proj(pyproj.Proj(orig_crs),
pyproj.Proj(dest_crs),
always_xy=True)
[docs]def reproject_grid(x_grid, y_grid, orig_crs, dest_crs):
"""
Reproject a grid from one crs to another
Parameters
----------
x_grid :
x-coordinates
y_grid :
y-coordinates
orig_crs: pyproj.CRS
original CRS of the grid
dest_crs: pyproj.CRS
CRS of the grid to be reprojected to
Returns
-------
x_trafo, y_trafo :
Grid coordinates in reprojected crs
"""
project = _get_pyproj_trafo(orig_crs, dest_crs)
x_trafo, y_trafo = project.transform(x_grid, y_grid)
return x_trafo, y_trafo
[docs]def reproject_poly(poly, orig_crs, dest_crs):
"""
Reproject a polygon from one crs to another
Parameters
----------
poly : shapely Polygon
Polygon
orig_crs: pyproj.CRS
original CRS of the polygon
dest_crs: pyproj.CRS
CRS of the polygon to be reprojected to
Returns
-------
poly : shapely Polygon
Polygon in desired projection
"""
project = _get_pyproj_trafo(orig_crs, dest_crs)
return sh.ops.transform(project.transform, poly)
def _line_to_pnts(gdf_lines, res, to_meters):
"""
Convert a GeoDataFrame with LineString geometries to
Point geometries, where Points are placed at a specified distance
(in meters, if applicable) along the original LineString. Each line is
reduced to at least two points.
Parameters
----------
gdf_lines : gpd.GeoDataFrame
Geodataframe with line geometries
res : float
Resolution (distance) apart from which the generated Points
should be approximately placed.
to_meters : bool
If True, res is interpreted as meters, and geometries are projected to
an equal area projection for disaggregation.
Returns
-------
gdf_points : gpd.GeoDataFrame
Geodataframe with a double index, first for line geometries,
second for the point disaggregation of the lines (i.e. one Point
per row).
See also
--------
climada.util.coordinates.compute_geodesic_lengths
"""
if gdf_lines.empty:
return gdf_lines
# Needed because gdf.explode(index_parts=True) requires numeric index
idx = gdf_lines.index.to_list() #To restore the naming of the index
gdf_points = gdf_lines.copy().reset_index(drop=True)
if to_meters:
line_lengths = u_coord.compute_geodesic_lengths(gdf_points)
else:
line_lengths = gdf_lines.length
# Add warning if lines are too short w.r.t. resolution
failing_res_check_count = len(line_lengths[line_lengths > 10*res])
if failing_res_check_count > 0:
LOGGER.warning(
"%d lines with a length < 10*resolution were found. "
"Each of these lines is disaggregate to one point. "
"Reaggregatint values will thus likely lead to overestimattion. "
"Consider chosing a smaller resolution or filter out the short lines. ",
failing_res_check_count
)
line_fractions = [
_line_fraction(length, res)
for length in line_lengths
]
gdf_points['geometry_pnt'] = [
shgeom.MultiPoint([
line.interpolate(dist, normalized=True)
for dist in fractions
])
for line, fractions in zip(gdf_points.geometry, line_fractions)
]
gdf_points = _swap_geom_cols(
gdf_points, geom_to='geometry_orig', new_geom='geometry_pnt')
gdf_points = gdf_points.explode(index_parts=True)
gdf_points.index = gdf_points.index.set_levels(idx, level=0)
return gdf_points
def _line_fraction(length, res):
"""
Compute the fraction in which to divide a line of given length at given resolution
Parameters
----------
length : float
Length of a string
res : float
Resolution (length of a string element)
Returns
-------
np.ndarray
Array of the fraction at which to divide the string of given length
into points at the chosen resolution.
"""
nb_points = _pnts_per_line(length, res)
eff_res = 1 / nb_points
start = eff_res / 2
return np.arange(start, 1, eff_res)
def _pnts_per_line(length, res):
"""Calculate number of points fitting along a line, given a certain
resolution (spacing) res between points.
Parameters
----------
length : float
res : float
Returns
--------
int
Number of points along line
"""
return int(max(np.round(length / res), 1))
def _swap_geom_cols(gdf, geom_to, new_geom):
"""
Change which column is the geometry column.
Conserves the crs of the original geometry column.
Parameters
----------
gdf : gpd.GeoDataFrame
Input geodatafram
geom_to : string
New name of the current 'geometry' column
new_geom : string
Column that should be set as the 'geometry' column. The column
new_geom is renamed to 'geometry'
Returns
-------
gdf_swap : gpd.GeoDataFrame
Copy of gdf with the new geometry column
"""
gdf_swap = gdf.rename(columns = {'geometry': geom_to})
gdf_swap.rename(columns = {new_geom: 'geometry'}, inplace=True)
gdf_swap.set_geometry('geometry', inplace=True, crs=gdf.crs)
return gdf_swap
# TODO: To be removed in a future iteration and included directly into the impact class
[docs]def set_imp_mat(impact, imp_mat):
"""
Set Impact attributes from the impact matrix. Returns a copy.
Overwrites eai_exp, at_event, aai_agg, imp_mat.
Parameters
----------
impact : Impact
Impact instance.
imp_mat : sparse.csr_matrix
matrix num_events x num_exp with impacts.
Returns
-------
imp : Impact
Copy of impact with eai_exp, at_event, aai_agg, imp_mat set.
"""
imp = copy.deepcopy(impact)
imp.eai_exp = eai_exp_from_mat(imp_mat, imp.frequency)
imp.at_event = at_event_from_mat(imp_mat)
imp.aai_agg = aai_agg_from_at_event(imp.at_event, imp.frequency)
imp.imp_mat = imp_mat
return imp
[docs]def eai_exp_from_mat(imp_mat, freq):
"""
Compute impact for each exposures from the total impact matrix
Parameters
----------
imp_mat : sparse.csr_matrix
matrix num_events x num_exp with impacts.
frequency : np.array
frequency of events
Returns
-------
eai_exp : np.array
expected impact for each exposure within a period of 1/frequency_unit
"""
freq_mat = freq.reshape(len(freq), 1)
return imp_mat.multiply(freq_mat).sum(axis=0).A1
[docs]def at_event_from_mat(imp_mat):
"""
Compute impact for each hazard event from the total impact matrix
Parameters
----------
imp_mat : sparse.csr_matrix
matrix num_events x num_exp with impacts.
Returns
-------
at_event : np.array
impact for each hazard event
"""
return np.squeeze(np.asarray(np.sum(imp_mat, axis=1)))
[docs]def aai_agg_from_at_event(at_event, freq):
"""
Aggregate impact.at_event
Parameters
----------
at_event : np.array
impact for each hazard event
frequency : np.array
frequency of event
Returns
-------
float
average impact within a period of 1/frequency_unit, aggregated
"""
return sum(at_event * freq)
```