flopy.utils.geometry module

Container objects for working with geometric information

class Collection(geometries=())

Bases: list

The collection object is container for a group of flopy geometries

This class acts as a base class for MultiPoint, MultiLineString, and MultiPolygon classes. This class can also accept a mix of geometries and act as a stand alone container.

Parameters:geometries (list) – list of flopy.util.geometry objects

bounds

Method to calculate the bounding box of the collection

Returns: Return type:tuple (xmin, ymin, xmax, ymax)

plot(ax=None, **kwargs)

Plotting method for collection

Parameters:

• ax (matplotlib.axes object) –
• kwargs (keyword arguments) – matplotlib keyword arguments

Returns:

Return type:

matplotlib.axes object

class LineString(coordinates)

Bases: flopy.utils.geometry.Shape

bounds

has_z = False

plot(ax=None, **kwargs)

pyshp_parts

shapeType = 3

type = 'LineString'

x

y

z

class MultiLineString(linestrings=())

Bases: flopy.utils.geometry.Collection

Container for housing and describing multilinestring geometries (e.g. to be

read or written to shapefiles or other geographic data formats)

polygons : list

list of flopy.utils.geometry.LineString objects

class MultiPoint(points=())

Bases: flopy.utils.geometry.Collection

Container for housing and describing multipoint geometries (e.g. to be

read or written to shapefiles or other geographic data formats)

polygons : list

list of flopy.utils.geometry.Point objects

class MultiPolygon(polygons=())

Bases: flopy.utils.geometry.Collection

Container for housing and describing multipolygon geometries (e.g. to be

read or written to shapefiles or other geographic data formats)

polygons : list

list of flopy.utils.geometry.Polygon objects

class Point(*coordinates)

Bases: flopy.utils.geometry.Shape

bounds

has_z = False

plot(ax=None, **kwargs)

pyshp_parts

shapeType = 1

type = 'Point'

x

y

z

class Polygon(exterior, interiors=None)

Bases: flopy.utils.geometry.Shape

bounds

get_patch(**kwargs)

patch

plot(ax=None, **kwargs)

Plot the feature. :param ax: :type ax: matplotlib.pyplot axes instance :param Accepts keyword arguments to descartes.PolygonPatch. Requires the: :param descartes package (pip install descartes).:

pyshp_parts

shapeType = 5

type = 'Polygon'

class Shape(shapetype, coordinates=None, exterior=None, interiors=None)

Bases: object

Parent class for handling geo interfacing, do not instantiate directly

type : str

shapetype string

coordinates : list or tuple

list of tuple of point or linestring coordinates

exterior : list or tuple

2d list of polygon coordinates

interiors : list or tuple

2d or 3d list of polygon interiors

static from_geojson(geo_interface)

Method to load from geojson

Parameters:geo_interface (geojson, dict) – geojson compliant representation of a linestring Returns: Return type:Polygon, LineString, or Point

geojson

get_polygon_area(geom)

Calculate the area of a closed polygon

Parameters:geom (geospatial representation of polygon) –

accepted types:

vertices np.array([(x, y),….]) geojson.Polygon shapely.Polygon shapefile.Shape

Returns:area – area of polygon centroid Return type:float

get_polygon_centroid(geom)

Calculate the centroid of a closed polygon

Parameters:geom (geospatial representation of polygon) –

accepted types:

vertices np.array([(x, y),….]) geojson.Polygon shapely.Polygon shapefile.Shape

Returns:centroid – (x, y) of polygon centroid Return type:tuple

is_clockwise(*geom)

Determine if a ring is defined clockwise

Parameters:*geom (geospatial representation of polygon) –

accepted types:

vertices [(x, y),….] geojson.Polygon shapely.Polygon shapefile.Shape x and y vertices: [x1, x2, x3], [y1, y2, y3]

Returns:clockwise – True when the ring is defined clockwise, False otherwise Return type:bool

point_in_polygon(xc, yc, polygon)

Use the ray casting algorithm to determine if a point is within a polygon. Enables very fast intersection calculations!

Parameters:

• xc (np.ndarray) – 2d array of xpoints
• yc (np.ndarray) – 2d array of ypoints
• polygon (iterable (list)) – polygon vertices [(x0, y0),….(xn, yn)] note: polygon can be open or closed

Returns:

mask – True value means point is in polygon!

Return type:

np.array

project_point_onto_xc_line(line, pts, d0=0, direction='x')

Method to project points onto a cross sectional line that is defined by distance. Used for plotting MODPATH results on to a cross section!

line : list or np.ndarray

numpy array of [(x0, y0), (x1, y1)] that defines the line to project on to

pts : list or np.ndarray

numpy array of [(x, y),] points to be projected

d0 : distance offset along line of min(xl) direction : string

projection direction “x” or “y”

Returns:np.ndarray of projected [(x, y),] points

rotate(x, y, xoff, yoff, angrot_radians)

Given x and y array-like values calculate the rotation about an arbitrary origin and then return the rotated coordinates.

shape(pyshp_shpobj)

Convert a pyshp geometry object to a flopy geometry object.

Parameters:pyshp_shpobj (shapefile._Shape instance) – Returns:shape Return type:flopy.utils.geometry Polygon, Linestring, or Point

Notes

Currently only regular Polygons, LineStrings and Points (pyshp types 5, 3, 1) supported.

Examples

>>> import shapefile as sf
>>> from flopy.utils.geometry import shape
>>> sfobj = sf.Reader('shapefile.shp')
>>> flopy_geom = shape(list(sfobj.iterShapes())[0])

transform(x, y, xoff, yoff, angrot_radians, length_multiplier=1.0, inverse=False)

Given x and y array-like values calculate the translation about an arbitrary origin and then return the rotated coordinates.