Adding an ID and applying a buffer
This step aims at preprocessing a vector file containing observation points or polygons. It adds an ID column if one does not already exist, and can also apply a buffer to erode or dilate observations.
It is optional if one uses a dataset which already contains an ID column and does not which to apply a buffer to it.
The input parameters are:
- obs_path : Path of vector file containing observation points or polygons to preprocess
- export_path : Path used to export the resulting preprocessed observation points or polygons
- buffer (optional) : Length in meters of the buffer used to dilate (positive integer) or erode (negative integer) the observations. If None, no buffer is applied. Some observations may disappear completely if a negative buffer is applied.
- name_column (optional) : Name of the column used to identify observations. If the column doesn't already exists, it is added as an integer between 1 and the number of observations. The default is "id".
The output is a vector file at export_path derived from the vector file at obs_path, with up to two modifications :
- An ID attribute named after the name_column parameter is added, if not already present.
- A buffer can be applied, positive or negative
How to use
From a script
from fordead.validation.preprocess_obs import preprocess_obs preprocess_obs(obs_path = <obs_path>, export_path = <export_path>, name_column = <name_column>, buffer = <buffer>)
From the command line
fordead preprocess_obs [OPTIONS]
See detailed documentation on the site
How it works
Importing the vector file containing observations
The vector file at obs_path is imported using the geopandas package.
Adding an ID column to the vector
If name_column does not exist in the vector file, each observation is attributed an ID from 1 to the length of the GeoDataFrame object.
Functions used: attribute_id_to_obs()
Applying a buffer
If the buffer parameter is used, a buffer is applied on the observations to erode if buffer is negative, or to dilate if it is positive.
Functions used: buffer_obs()
Exporting the resulting the vector file
The modified GeoDataFrame object is exported to export_path.