Make grids from bounds¶
- class Gridlooper(gridsize, mask, gridbuffer=0, parallelizer=None, concat=False, clip=True, keep_geom_type=True, verbose=False)[source]¶
Bases:
objectRun functions in a loop cellwise based on a grid.
- Parameters:
gridsize (
int) – Size of the grid cells in units of the crs (meters, degrees).mask (
GeoDataFrame|GeoSeries|Geometry) – Geometry object to create a grid around.gridbuffer (
int) – Units to buffer each gridcell by. For edge cases. Defaults to 0.clip (
bool) – If True (default) geometries are clipped by the grid cells. If False, all geometries that intersect will be selected in each iteration.verbose (
bool) – Whether to print progress. Defaults to False.keep_geom_type (
bool) – Whether to keep only the input geometry types after clipping. Defaults to True.parallelizer (Parallel | None)
concat (bool)
Examples:¶
Get some points and some polygons.
>>> import sgis as sg >>> points = sg.read_parquet_url("https://media.githubusercontent.com/media/statisticsnorway/ssb-sgis/main/tests/testdata/points_oslo.parquet") >>> points["idx"] = points.index >>> buffered = sg.buff(points, 100) >>> buffered idx geometry 0 0 POLYGON ((263222.700 6651184.900, 263222.651 6... 1 1 POLYGON ((272556.100 6653369.500, 272556.051 6... 2 2 POLYGON ((270182.300 6653032.700, 270182.251 6... 3 3 POLYGON ((259904.800 6650339.700, 259904.751 6... 4 4 POLYGON ((272976.200 6652889.100, 272976.151 6... .. ... ... 995 995 POLYGON ((266901.700 6647844.500, 266901.651 6... 996 996 POLYGON ((261374.000 6653593.400, 261373.951 6... 997 997 POLYGON ((263642.900 6645427.000, 263642.851 6... 998 998 POLYGON ((269326.700 6650628.000, 269326.651 6... 999 999 POLYGON ((264670.300 6644239.500, 264670.251 6...
[1000 rows x 2 columns]
Instantiate a gridlooper.
>>> looper = sg.Gridlooper(gridsize=200, mask=buffered, concat=True, parallelizer=sg.Parallel(1, backend="multiprocessing"))
Run the function clean_overlay in a gridloop.
>>> results = looper.run( ... sg.clean_overlay, ... points, ... buffered, ... ) >>> results idx_1 idx_2 geometry 0 220 220 POINT (254575.200 6661631.500) 1 735 735 POINT (256337.400 6649931.700) 2 575 575 POINT (256369.200 6650413.300) 3 39 39 POINT (256142.300 6650526.300) 4 235 235 POINT (256231.300 6650720.200) ... ... ... ... 1481 711 795 POINT (272845.500 6655048.800) 1482 711 711 POINT (272845.500 6655048.800) 1483 757 757 POINT (273507.600 6652806.600) 1484 457 457 POINT (273524.400 6652979.900) 1485 284 284 POINT (273650.800 6653000.500)
[1486 rows x 3 columns]
- add_grid_id(gdf, gridsize, out_column='SSBID')[source]¶
Adds an SSB grid ID column to a GeoDataFrame of points.
The GeoDataFrame must have 25833 as crs (UTM 33 N).
- Parameters:
gdf (
GeoDataFrame) – A GeoDataFrame.gridsize (
int) – Size of the grid in meters.out_column (
str) – Name of column for the grid id.
- Return type:
GeoDataFrame- Returns:
The input GeoDataFrame with a new grid id column.
- Raises:
ValueError – If the GeoDataFrame does not have 25833 as crs.
- bounds_to_points(gdf, copy=True)[source]¶
Creates a 4-noded multipoint around the geometry in each row of a GeoDataFrame.
- Parameters:
gdf (
GeoDataFrame|GeoSeries) – The GeoDataFrame.copy (
bool) – Defaults to True.
- Return type:
GeoDataFrame|GeoSeries- Returns:
GeoDataFrame of multipoints with same length and index as ‘gdf’.
Examples:¶
>>> import sgis as sg >>> from shapely.geometry import MultiPoint, Point >>> gdf = sg.to_gdf([MultiPoint([(0, 0), (1, 1)]), Point(0, 0)]) >>> gdf geometry 0 MULTIPOINT (0.00000 0.00000, 1.00000 1.00000) 1 POINT (0.00000 0.00000)
>>> sg.bounds_to_points(gdf) geometry 0 MULTIPOINT (1.00000 0.00000, 1.00000 1.00000, ... 1 MULTIPOINT (0.00000 0.00000)
- bounds_to_polygon(gdf, copy=True)[source]¶
Creates a box around the geometry in each row of a GeoDataFrame.
- Parameters:
gdf (
GeoDataFrame|GeoSeries) – The GeoDataFrame.copy (
bool) – Defaults to True.
- Return type:
GeoDataFrame|GeoSeries- Returns:
GeoDataFrame of box polygons with length and index of ‘gdf’.
Examples:¶
>>> import sgis as sg >>> gdf = sg.to_gdf([MultiPoint([(0, 0), (1, 1)]), Point(0, 0)]) >>> gdf geometry 0 MULTIPOINT (0.00000 0.00000, 1.00000 1.00000) 1 POINT (0.00000 0.00000)
>>> sg.bounds_to_polygon(gdf) geometry 0 POLYGON ((1.00000 0.00000, 1.00000 1.00000, 0.... 1 POLYGON ((0.00000 0.00000, 0.00000 0.00000, 0....
- get_total_bounds(*geometries, strict=False)[source]¶
Get a combined total bounds of multiple geometry objects.
- Return type:
tuple[float,float,float,float]- Parameters:
geometries (GeoDataFrame | GeoSeries | Geometry)
strict (bool)
- gridloop(func, gridsize, mask, gridbuffer=0, clip=True, keep_geom_type=True, verbose=False, args=None, kwargs=None, parallelizer=None)[source]¶
Runs a function in a loop cellwise based on a grid.
Creates grid from a mask, and runs the function for each cell with all GeoDataFrame keyword arguments clipped to the cell extent.
- Parameters:
func (
Callable) – Function to run cellwise.mask (
GeoDataFrame|GeoSeries|Geometry) – Geometry object to create a grid around.gridsize (
int) – Size of the grid cells in units of the crs (meters, degrees).gridbuffer (
int) – Units to buffer each gridcell by. For edge cases. Defaults to 0.clip (
bool) – If True (default) geometries are clipped by the grid cells. If False, all geometries that intersect will be selected in each iteration.verbose (
bool) – Whether to print progress. Defaults to False.keep_geom_type (
bool) – Whether to keep only the input geometry types after clipping. Defaults to True.args (
tuple|None) – Positional arguments to pass to the function. Arguments of type GeoDataFrame or GeoSeries will be clipped by the grid cells in a loop.kwargs (
dict|None) – Keyword arguments to pass to the function. Arguments of type GeoDataFrame or GeoSeries will be clipped by the grid cells in a loop.parallelizer (
Parallel|None) – Optional instance of sgis.Parallel, to run the function in parallel.
- Return type:
list[Any]- Returns:
List of results with the same length as number of grid cells.
- Raises:
TypeError – If args or kwargs has a wrong type
Examples:¶
Get some points and some polygons.
>>> import sgis as sg >>> points = sg.read_parquet_url("https://media.githubusercontent.com/media/statisticsnorway/ssb-sgis/main/tests/testdata/points_oslo.parquet") >>> points["idx"] = points.index >>> buffered = sg.buff(points, 100) >>> buffered idx geometry 0 0 POLYGON ((263222.700 6651184.900, 263222.651 6... 1 1 POLYGON ((272556.100 6653369.500, 272556.051 6... 2 2 POLYGON ((270182.300 6653032.700, 270182.251 6... 3 3 POLYGON ((259904.800 6650339.700, 259904.751 6... 4 4 POLYGON ((272976.200 6652889.100, 272976.151 6... .. ... ... 995 995 POLYGON ((266901.700 6647844.500, 266901.651 6... 996 996 POLYGON ((261374.000 6653593.400, 261373.951 6... 997 997 POLYGON ((263642.900 6645427.000, 263642.851 6... 998 998 POLYGON ((269326.700 6650628.000, 269326.651 6... 999 999 POLYGON ((264670.300 6644239.500, 264670.251 6...
[1000 rows x 2 columns]
Run the function clean_overlay where the data is clipped to a grid of 1000x1000 meters. Args are the first two arguments of clean_overlay, kwargs are additional keyword arguments.
>>> resultslist = sg.gridloop( ... func=sg.clean_overlay, ... mask=buffered, ... gridsize=1000, ... args=(points, buffered), ... kwargs={"how": "intersection"} ... ) >>> type(resultslist) list
>>> results = pd.concat(resultslist, ignore_index=True) >>> results idx_1 idx_2 geometry 0 220 220 POINT (254575.200 6661631.500) 1 735 735 POINT (256337.400 6649931.700) 2 575 575 POINT (256369.200 6650413.300) 3 39 39 POINT (256142.300 6650526.300) 4 235 235 POINT (256231.300 6650720.200) ... ... ... ... 1481 711 795 POINT (272845.500 6655048.800) 1482 711 711 POINT (272845.500 6655048.800) 1483 757 757 POINT (273507.600 6652806.600) 1484 457 457 POINT (273524.400 6652979.900) 1485 284 284 POINT (273650.800 6653000.500)
[1486 rows x 3 columns]
- make_grid(obj, gridsize, *, crs=None, clip_to_bounds=False)[source]¶
Create a polygon grid around geometries.
Creates a GeoDataFrame of grid cells of a given size around the bounds of a given GeoDataFrame. The corners are rounded to the nearest integer.
- Parameters:
obj (
GeoDataFrame|GeoSeries|Geometry|tuple) – GeoDataFrame, GeoSeries, shapely geometry or bounding box (an iterable with four values (minx, miny, maxx, maxy)).gridsize (
int|float) – Length of the grid cell walls.crs (
CRS|None) – Coordinate reference system if ‘obj’ is not GeoDataFrame or GeoSeries.clip_to_bounds (
bool) – Whether to clip the grid to the total bounds of the geometries. Defaults to False.
- Return type:
GeoDataFrame- Returns:
GeoDataFrame with grid polygons.
- Raises:
ValueError – crs can only be None if obj is GeoDataFrame/GeoSeries.
- make_grid_from_bbox(minx, miny, maxx, maxy, *_, gridsize, crs)[source]¶
Creates a polygon grid from a bounding box.
Creates a GeoDataFrame of grid cells of a given size within the given maxumum and mimimum x and y values.
- Parameters:
minx (
int|float) – Minumum x coordinate.miny (
int|float) – Minumum y coordinate.maxx (
int|float) – Maximum x coordinate.maxy (
int|float) – Maximum y coordinate.gridsize (
int|float) – Length of the grid walls.crs (
CRS|int|str) – Coordinate reference system.
- Return type:
GeoDataFrame- Returns:
GeoDataFrame with grid geometries.
- make_ssb_grid(gdf, gridsize=1000, add=1)[source]¶
Creates a polygon grid around a GeoDataFrame with an SSB id column.
Creates a grid that follows the grids produced by Statistics Norway. The GeoDataFrame must have 25833 as crs (UTM 33 N).
Courtesy https://gis.stackexchange.com/questions/269243/creating-polygon-grid-using-geopandas
- Parameters:
gdf (
GeoDataFrame|GeoSeries) – A GeoDataFrame.gridsize (
int) – Size of the grid in meters.add (
int|float) – Number of grid cells to add on each side, to make sure all data is covered by the grid.
- Return type:
GeoDataFrame- Returns:
GeoDataFrame with grid geometries and a column ‘SSBID’.
- Raises:
ValueError – If the GeoDataFrame does not have 25833 as crs.
TypeError – if gdf has wrong type.