flopy.utils.rasters module

class Raster(array, bands, crs, transform, nodataval, driver='GTiff', rio_ds=None)

Bases: object

The Raster object is used for cropping, sampling raster values, and re-sampling raster values to grids, and provides methods to plot rasters and histograms of raster digital numbers for visualization and analysis purposes.

Parameters:

• array (np.ndarray) – a three dimensional array of raster values with dimensions defined by (raster band, nrow, ncol)
• bands (tuple) – a tuple of raster bands
• crs (int, string, rasterio.crs.CRS object) – either a epsg code, a proj4 string, or a CRS object
• transform (affine.Affine object) – affine object, which is used to define geometry
• nodataval (float) – raster no data value
• rio_ds (DatasetReader object) – rasterIO dataset Reader object

Notes

Examples

>>> from flopy.utils import Raster
>>>
>>> rio = Raster.load("myraster.tif")

FLOAT32 = (<class 'float'>, <class 'float'>, <class 'numpy.float32'>, <class 'numpy.float64'>)

FLOAT64 = (<class 'numpy.float64'>,)

INT16 = (<class 'numpy.int16'>,)

INT32 = (<class 'int'>, <class 'int'>, <class 'numpy.int32'>, <class 'numpy.int64'>)

INT64 = (<class 'numpy.int64'>,)

INT8 = (<class 'numpy.int8'>,)

bands

Returns a tuple of raster bands

bounds

Returns a tuple of xmin, xmax, ymin, ymax boundaries

crop(polygon, invert=False)

Method to crop a new raster object from the current raster object

Parameters:

• polygon (list, geojson, shapely.geometry, shapefile.Shape) –

  crop method accepts any of these geometries:

  a list of (x, y) points, ex. [(x1, y1), …] geojson Polygon object shapely Polygon object shapefile Polygon shape flopy Polygon shape

• invert (bool) – Default value is False. If invert is True then the area inside the shapes will be masked out

get_array(band, masked=True)

Method to get a numpy array corresponding to the provided raster band. Nodata vals are set to np.NaN

Parameters:

• band (int) – band number from the raster
• masked (bool) – determines if nodatavals will be returned as np.nan to the user

Returns:

Return type:

np.ndarray

histogram(ax=None, **kwargs)

Method to plot a histogram of digital numbers

Parameters:

• ax (matplotlib.pyplot.axes) – optional matplotlib axes for plotting
• **kwargs – matplotlib keyword arguments see matplotlib documentation for valid arguments for histogram

Returns:

ax

Return type:

matplotlib.pyplot.axes

static load(raster)

Static method to load a raster file into the raster object

Parameters:raster (str) – Returns: Return type:Raster object

nodatavals

Returns a Tuple of values used to define no data

plot(ax=None, contour=False, **kwargs)

Method to plot raster layers or contours.

Parameters:

• ax (matplotlib.pyplot.axes) – optional matplotlib axes for plotting
• contour (bool) – flag to indicate creation of contour plot
• **kwargs – matplotlib keyword arguments see matplotlib documentation for valid arguments for plot and contour.

Returns:

ax

Return type:

matplotlib.pyplot.axes

resample_to_grid(xc, yc, band, method='nearest')

Method to resample the raster data to a user supplied grid of x, y coordinates.

x, y coordinate arrays should correspond to grid vertices

Parameters:

• xc (np.ndarray or list) – an array of x-cell centers
• yc (np.ndarray or list) – an array of y-cell centers
• band (int) – raster band to re-sample
• method (str) –

  scipy interpolation method options

  ”linear” for bi-linear interpolation “nearest” for nearest neighbor “cubic” for bi-cubic interpolation

Returns:

Return type:

np.array

sample_point(*point, band=1)

Method to get nearest raster value at a user provided point

Parameters:

• *point (point geometry representation) – accepted data types: x, y values : ex. sample_point(1, 3, band=1) tuple of x, y: ex sample_point((1, 3), band=1) shapely.geometry.Point geojson.Point flopy.geometry.Point
• band (int) – raster band to re-sample

Returns:

value

Return type:

float

sample_polygon(polygon, band, invert=False)

Method to get an unordered list of raster values that are located within a arbitrary polygon

Parameters:

• polygon (list, geojson, shapely.geometry, shapefile.Shape) –

  sample_polygon method accepts any of these geometries:

  a list of (x, y) points, ex. [(x1, y1), …] geojson Polygon object shapely Polygon object shapefile Polygon shape flopy Polygon shape

• band (int) – raster band to re-sample
• invert (bool) – Default value is False. If invert is True then the area inside the shapes will be masked out

Returns:

Return type:

np.ndarray of unordered raster values

write(name)

Method to write raster data to a .tif file

Parameters:name (str) – output raster .tif file name

xcenters

Returns a np.ndarray of raster x cell centers

ycenters

Returns a np.ndarray of raster y cell centers