Reference

For simple calculation, the recommended way to run NICHE is through the Niche class, as demonstrated in the Tutorials.

In the low level interface, it is possible to run the three classes Vegetation, Acidity and NutrientLevel directly using numpy arrays. This allows a greater flexibility and control over the details of the calculation,

Niche

class niche_vlaanderen.Niche(ct_acidity=None, ct_soil_mlw_class=None, ct_soil_codes=None, lnk_acidity=None, ct_seepage=None, ct_vegetation=None, ct_management=None, ct_nutrient_level=None, ct_mineralisation=None)[source]

Creates a new Niche object

A niche object can be used to predict vegetation types according to the NICHE Vlaanderen model.

The default codetables are used unless other tables are supplied to the constructor.

Parameters:

lnk_* (ct_*) – path Optionally, paths to codetables can be provided. These will override the standard codetables used by Niche.

plot(key, ax=None, fixed_scale=True)[source]

Plots the result or input of a Niche object

Creates a plot of an input layer of a Niche object or of the result of a Niche object.

Note that depending on your matplotlib environment you may still have to call the matplotlib show method to actually show the plot:

>>> myniche.plot(11)
>>> import matplotlib.pyplot as plt
>>> plt.show()
Parameters:

  • key (veg_code (1..28) or input_code) – key of the vegetation type that should be plotted, eg myniche.plot(7) or key of the input layer you want to plot eg myniche(“mhw”). If deviation was calculated with the model, this can also be plotted, by using input_code_veg_code eg mhw_14

  • ax (matplotlib.axes.Axes) – optional axis parameter. Can be specified when you want to plot different plots in one layout

  • fixed_scale (boolean (default: True)) – Use a fixed scale

Returns:

ax – Can be used to update the plot (eg change the title).

Return type:

matplotlib.axes.Axes

plot_detail(key, limit_legend=True, cmap='tab20')[source]

Detailed plot for a vegetation type key: veg_code (1..28)

key of the vegetation type that should be plotted

limit_legend: boolean

limits the legend to the types present in the figure

cmap: colormap

colormap to use for the maps. Note that 9 combinations of presence/absence are possible, so keep this in mind if changing from the default value.

read_config_file(config, overwrite_ct=False)[source]

Sets the input based on an input file, without running it

Configures a model based on a config file

Parameters:

overwrite_ct – bool (False) Allows the user to override the default codetables (after the class has been initialized).

run(full_model=True, deviation=False, strict_checks=True)[source]

Run the niche model

Runs niche Vlaanderen model. Requires that the necessary input values have been added using set_input.

Parameters:

  • full_model (bool) – Uses the full niche model. The simple model only uses mhw, mlw and soil_code as input.

  • deviation (bool) – Create the maps with the difference between the needed MHW and MLW and the actual MHW/MLW for a vegetation type.

  • strict_checks (bool) – By default running a model will fail if impossible combinations of MxW exist somewhere in the input files. By disabling strict checks models can still be run. It will still emit a warning. Note that this is provided to be backwards compatibility and it is recommended to fix the data rather than disabling this.

run_config_file(config, overwrite_ct=False)[source]

Runs Niche using a configuration file

This will configure the model, run and output as specified.

Parameters:

  • config – string path to a config file

  • overwrite_ct – boolean (False) overwrite codetables using the values specified in the configuration file.

set_input(key, value)[source]

Adds a raster or numeric value as input layer

Parameters:

  • key (string) – The type of grid that you want to assign (eg msw, soil_code, …). Possible options are listed in https://inbo.github.io/niche_vlaanderen/cli.html#id1

  • value (string / number) – Path to a file containing the grid. Can be a folder for certain grid types (eg ArcGIS rasters). Can also be a number: in that case a constant value is applied everywhere.

property table

Dataframe containing the potential area (ha) per vegetation type

write(folder, overwrite_files=False, detailed_files=False)[source]

Saves the model results to a folder

Saves the model results to a folder. Files will be written as geotiff. Vegetation files have names V1 … V28 Abiotic files are exported as well (nutrient_level.tif and acidity.tif) if they were not input files.

Parameters:

  • folder (string) – Output folder to which files will be written. Parent directory must already exist.

  • overwrite_files (bool) – Overwrite files when saving. Note writing will fail if any of the files to be written already exists.

  • detailed_files (bool) – Save detailed information on factor affecting vegetation possibility

zonal_stats(vectors, outside=True, attribute=None, vegetation_types=None, upscale=1)[source]

Calculates zonal statistics using vectors

Parameters:

  • vectors (path to a vector source or geo-like python objects) –

    you can specify a path to a vector file eg “../test.shp”, or pass geo objects from other python functions.

    Note that the vector should be in the same coordinate system as the raster.

  • outside (bool (default: True)) – report values outside shapes as well. The area which is not covered by any shapefile will get shape_id -1.

  • attribute (string(default None):) – attribute of the vector source that will be exported along in the table.

  • vegetation_types (List | None) – optional list of vegetation types (as integer number) for which the statistics must be calculated. Calculation will happen for all niche vegetation types by default.

  • upscale (int) – upscaling factor: decrease the cell size by this factor to increase the resolution

Returns:

table

Return type:

pandas.DataFrame

Niche Delta

class niche_vlaanderen.NicheDelta(n1, n2)[source]

Class containing the difference between two niche runs

The difference can be visualized using the plot method. It is also possible to derive a table with the area’s according to each group.

See the tutorial at: Comparing Niche classes

plot(key, ax=None)[source]

Plots the difference between two classes

Parameters:

key (number) – The vegetation code (1-28)

property table

Return a summarized dataframe for a NicheDelta object

Returns:

df

Return type:

pandas.DataFrame

write(folder, overwrite_files=False)[source]

Writes the difference grids to grid files.

The differences are coded using these values:

  • 0: “not present in both models”

  • 1: “present in both models”

  • 2: “only in model 1”

  • 3: “only in model 2”

  • 4: “nodata in one model”

Parameters:

  • folder (path) – Path to which the output files will be written.

  • overwrite_files (bool) – Whether files should be overwritten on save.

Flooding

class niche_vlaanderen.Flooding(depths=None, duration=None, frequency=None, lnk_potential=None, potential=None, name='')[source]

Predict the vegetation response to (frequent) flooding

A Flooding object can be used to predict the response of vegetation to (frequent) flooding.

The code tables used can be overwritten when initializing the object. Optionally also a name can be given which is used in plots and output files.

calculate(depth_file, frequency, period, duration)[source]

Calculate a floodplain object

Parameters:

depth_file (filename) – The filename containing a classified grid with inundation dephts. The classes used must correspond to the codes in the depths.csv code table.

frequency: code

The frequency with which flooding occurs, eg T2, T50. Valid values are given in the frequency.csv code table.

period: winter|summer

period in which the flooding occurs. Must be either “summer” or “winter”

duration: code

Period with which the flooding occurs, from duration.csv

combine(niche_result)[source]

Combines a Flooding model with a Niche model

Both models must be run prior to combining them. The niche model will act as a “mask” making areas where Niche predicts a vegetation type to be not present are set to “not combinable”.

Parameters:

niche_result (Niche) – Niche model that must be run prior to running combine.

Returns:

combined

Return type:

Flooding

property table

Dataframe containing the potential area (ha) per vegetation type

write(folder, overwrite_files=False)[source]

Writes the floodplain grids to grid files.

The differences are coded using the values specified in the potential.csv table.

Parameters:

  • folder (path) – Path to which the output files will be written.

  • overwrite_files (bool) – Overwrite files when saving. Note writing will fail if any of the files to be written already exists.

Validation

class niche_vlaanderen.NicheValidation(niche, map, mapping_file=None, upscale=5, id=None)[source]

Creates a new NicheValidation object

Overlays a vegetation map with niche in order to obtain the accuracy of the model.

Parameters:

  • niche – niche_vlaanderen.Niche Niche object containing predicted variables types according to niche. The model must have run prior to the overlay

  • map –

    Path Path to a file containing the vegetation map in one of the formats supported by fiona, eg shape. must contain these attributes: * HABx: vegetation type * pHABx: proportion of the vegetation type

    different vegetation types can be supplied, eg HAB1, HAB2, … for every HABx variable a proportion must be given.

  • mapping_file –

    Path | None optional file containing the mapping between habitat (HAB) code on the vegetation map and Niche vegetation types. The default mapping is a mapping of the BWK map (biologische waarderingskaart), and is part of the package at niche_vlaanderen/system_tables/hab_nich_join.csv

    If a mapping is provided by the user, it must contain a HAB and a NICHE column. Other columns are ignored.

  • upscale – int optional upscale value that is used to increase the resolution of the niche rasters while doing the overlay. instead of using only the cell center, the comparison between the vegetation map and the niche model is done at upscale*upscale places in the cell. Defaults to 5. More details in https://inbo.github.io/niche_vlaanderen/validation.html

  • id – str (optional) field to use as id for the provided map file. This id will be used in the overlay. If no id is supplied, the shape_index (row number) of the vector file will be used, starting from 0.

joined_map()[source]

Create a geopandas dataframe with all tables joined

overlay(upscale=5)[source]

Overlays the map and the niche object

write(path, overwrite_files=False)[source]

Write the result of the validation to a folder

path: string | pathlib.Path

Output folder to which files will be written. Parent directory must already exist.

overwrite_files: bool

Overwrite files when saving. Note writing will fail if any of the files to be written already exists.

Array based functions

At the lowest level of Niche sit a number of array-based classes which calculate the actual Niche model. These require numpy arrays as an input: all handling of gis files/… is done in the Niche class.

NutrientLevel

class niche_vlaanderen.NutrientLevel(ct_lnk_soil_nutrient_level=None, ct_management=None, ct_mineralisation=None, ct_soil_code=None, ct_nutrient_level=None)[source]

Class to calculate the NutrientLevel

The used codetables can be overwritten by using the corresponding ct_* arguments.

calculate(soil_code, msw, nitrogen_atmospheric, nitrogen_animal, nitrogen_fertilizer, management, inundation)[source]

Calculates the Nutrient level

Calculates the nutrient level based on a number of numpy arrays.

Parameters:

  • soil_code (numpy.array) – Array containing the soil codes. Values must be present in the soil_code table. -99 is used as no data value.

  • msw (numpy.array) – Array containing the mean spring waterlevel. numpy.nan is used as no data value

  • nitrogen_atmospheric (numpy.array) – Array containing the atmospheric deposition of Nitrogen. numpy.nan is used as no data value

  • nitrogen_animal (numpy.array) – Array containing the animal contribution of Nitrogen.numpy.nan is used as no data value

  • nitrogen_fertilizer (numpy.array) – Array containing the fertilizer contribution of Nitrogen.numpy.nan is used as no data value

  • management (numpy.array) – Array containing the management.

  • inundation – Array containing the inundation values.

Acidity

class niche_vlaanderen.Acidity(ct_acidity=None, ct_soil_mlw_class=None, ct_soil_codes=None, lnk_acidity=None, ct_seepage=None)[source]

Class to calculate the Acidity

The used codetables can be overwritten by using the corresponding ct_* arguments.

calculate(soil_class, mlw, inundation, seepage, minerality, rainwater)[source]

Parameters:

soil_class: numpy.array

Array containing the soil codes. Values must be present in the soil_code table. -99 is used as no data value.

mlw: numpy.array

Array containing the mean lowest waterlevel.

inundation: numpy.array

Array containing rate of inundation. https://inbo.github.io/niche_vlaanderen/invoer.html#overstroming-trofie-inundation-nutrient

seepage: numpy.array

Array containing the flux of groundwater at the location https://inbo.github.io/niche_vlaanderen/invoer.html#overstroming-trofie-inundation-nutrient

minerality: numpy.array

Array noting whether the groundwater is rich(1) or poor in minerals https://inbo.github.io/niche_vlaanderen/invoer.html#mineraalrijkdom-minerality

rainwater: numpy.array (optional)

Array denoting whether rainwater lenses occur. https://inbo.github.io/niche_vlaanderen/invoer.html#regenlens-rainwater

Vegetation

class niche_vlaanderen.Vegetation(ct_vegetation=None, ct_soil_code=None, ct_acidity=None, ct_management=None, ct_nutrient_level=None, ct_inundation=None)[source]

Helper class to calculate vegetation based on input arrays

This class helps predicting vegetation based on a number of input arrays. On initialization the input codetables are parsed (and validated).

Note that to use grid inputs (eg raster files) it is recommended to use the Niche Class

Parameters:

ct_vegetation (filename, .csv) – optional alternative classification table Must contain the columns mentioned in the documentation: https://inbo.github.io/niche_vlaanderen/codetables.html

calculate(soil_code, mhw, mlw, nutrient_level=None, acidity=None, management=None, inundation=None, return_all=True, full_model=True)[source]

Calculate vegetation types based on input arrays

Parameters:

return_all (boolean) – A boolean (default=True) whether all grids should be returned or only grids containing data.

Returns:

  • veg (dict) – A dictionary containing the different output arrays per veg_code value. 255 is used for nodata_veg values

  • expected (int) – Expected code in veg arrays if all conditions are met

  • veg_occurrence (dict) – A dictionary containing the percentage of the area where the vegetation can occur.

calculate_deviation(soil_code, mhw, mlw)[source]

Calculates the deviation between the mhw/mlw and the reference

This function calculates the difference between the mhw and mlw and the reference values for each vegetation type.

Positive values indicate too dry values, negative values indicate too wet values.

Values of zero indicate that the vegetation type can occur based on soil type and the value under consideration (mhw or mlw)

Returns:

difference – A dictionary containing the difference between the vegetation value an the actual value. Keys are eg mhw_01 for mhw and vegetation type 01

Return type:

dict

Example

The low level api can be used to calculate single values without having to create a full grid.

>>> import numpy as np
>>> import niche_vlaanderen
>>> nutrient_level = np.array([4])
>>> acidity = np.array([3])
>>> mlw = np.array([50])
>>> mhw = np.array([10])
>>> soil_codes = np.array([14])
>>> nv = niche_vlaanderen.Vegetation()
>>> veg_predict, veg_occurrence = nv.calculate(soil_codes,mhw,mlw,nutrient_level,acidity)
>>> veg_occurrence
{1: 0.0, 2: 0.0, 3: 0.0, 4: 0.0, 5: 0.0, 6: 0.0, 7: 1.0, 8: 1.0, 9: 0.0, 10: 0.0, 11: 0.0, 12: 1.0, 13: 0.0, 14: 0.0, 15: 0.0, 16: 1.0, 17: 0.0, 18: 0.0, 19: 0.0, 20: 0.0, 21: 0.0, 22: 0.0, 23: 0.0, 24: 0.0, 25: 0.0, 26: 0.0, 27: 0.0, 28: 0.0}

The potential vegetation types that can occur (in 100% of the area, since we have only one pixel) are 7, 8, 12 and 16.

If we also use the value foor floodings, this becomes:

>>> import numpy as np
>>> import niche_vlaanderen
>>> nutrient_level = np.array([4])
>>> acidity = np.array([3])
>>> mlw = np.array([50])
>>> mhw = np.array([10])
>>> soil_codes = np.array(["L1"])
>>> nv = niche_vlaanderen.Vegetation()
>>> inundation = np.array([1])
>>> veg_predict, veg_occurrence = nv.calculate(soil_codes,mhw,mlw,nutrient_level,acidity,inundation=inundation)
>>> veg_occurrence
{7: 1.0, 12: 1.0, 16: 1.0}

Vegetation type 8 is no longer a potential vegetation type.