Getting started

Installation

Python version: >=3.6. To use the full function of this package for processing raster and feature files, rasterio and pyshp are required.

To install hydro_raster from command window/terminal:

pip install hydro_raster

To install using github repo:

git clone https://github.com/mingxiaodong/hydro-raster
cd hydro-raster
pip install .

Examples of usage

A jupyter-notebook file is available to show a more detailed tutorial with outputs/plots of its codes.

  1. Read a raster file

from hydro_raster.Raster import Raster
from hydro_raster import get_sample_data
tif_file_name = get_sample_data('tif')
ras_obj = Raster(tif_file_name)

  1. Visualize a raster file

ras_obj.mapshow()
ras_obj.rankshow(breaks=[0, 10, 20, 30, 40, 50])

  1. Clip raster file

clip_extent = (340761, 341528, 554668, 555682) # left, right, bottom, top
ras_obj_cut = ras_obj.rect_clip(clip_extent) # raster can aslo be cut by a shapfile using 'clip' function
ras_obj_cut.mapshow()

  1. Rasterize polygons on a raster and return an index array with the same dimension of the raster array

shp_file_name = get_sample_data('shp')
index_array = ras_obj_cut.rasterize(shp_file_name)

  1. Change raster cell values within the polygons by adding a fixed value

ras_obj_new = ras_obj_cut.duplicate()
ras_obj_new.array[index_array] = ras_obj_cut.array[index_array]+20

  1. Show the edited raster with the shapefile polygons

import matplotlib.pyplot as plt
from hydro_raster.grid_show import plot_shape_file
fig, ax = plt.subplots(1, 2)
ras_obj_cut.mapshow(ax=ax[0])
plot_shape_file(shp_file_name, ax=ax[0], linewidth=1)
ras_obj_new.mapshow(ax=ax[1])
plot_shape_file(shp_file_name, ax=ax[1], linewidth=1)
# values can also be changed based on the attributes of each shapefile features