WaterPix

WaterPix is a hydrologic data-based model used to perform water balances at a pixel scale.

How to use the code

Before you start

There are two software options to run WaterPix on python:

• gdal
• arcpy

The two options are equivalent, the only difference is about the underlying library to process the geospatial data.

Requirements

• Python 2.7, preferably the Anaconda 64-bit distribution
• Python libraries:
  • scipy (https://pypi.python.org/pypi/scipy)
  • netCDF4 (https://pypi.python.org/pypi/netCDF4)
  • pandas (https://pypi.python.org/pypi/pandas)
  • rpy2 (https://pypi.python.org/pypi/rpy2)
• R 3.2.5 (https://cran.r-project.org/)
• R packages:
  • sp (https://cran.r-project.org/web/packages/sp/index.html)
  • gstat (https://cran.r-project.org/web/packages/gstat/index.html)
  • automap (https://cran.r-project.org/web/packages/automap/index.html)
• Additional:
  • gdal option
    • Python GDAL package (https://pypi.python.org/pypi/GDAL)
  • arcpy option
    • ArcMap software (http://desktop.arcgis.com/en/arcmap/)

Installation

1. Identify a folder in your computer that is recognized by python (e.g. ...\Lib\site-packages). You can check which folders are recognized by python with the following commands:

   >>> import sys
   >>> sys.path
   ['',
   'C:\\Program Files\\Anaconda2\\lib\\site-packages',
   ...

2. Download or clone the waterpix module from the online repository and place it into the folder recognized by python.
   • Download: https://github.com/gespinoza/waterpix/archive/master.zip
   • Clone: https://github.com/gespinoza/waterpix.git
3. Check that waterpix works and that all the required modules are installed.
   • gdal

     >>> from waterpix import wp_gdal
     >>> wa_gdal.__all__
     ['create_input_nc', 'run', 'output_nc_to_tiffs']

   • arcpy

     >>> from waterpix import wp_arcpy
     >>> wa_gdal.__all__
     ['create_input_nc', 'run', 'output_nc_to_tiffs']

   Note: If you get the following error:

   ImportError: No module named ...

   install the required modules, restart the python console, and repeat this step.

Example

from waterpix import wp_gdal

# Create input netcdf file
wp_gdal.create_input_nc(start_date='2010-01-01',
                        years=7,  # 2010 - 2016
                        cellsize=0.01078
                        basin_shp = r'C:\Temp\Basin_A.shp',
                        p_path = r'C:\Precipitation\chirps-v2.0_monthly_{yyyy}{mm}.tif',
                        et_path = r'C:\Evapotranspiration\L1_AET_{yyyy}{mm}.tif',
                        eto_path = r'C:\ReferenceET\ETref_mm-month-1_monthly_{yyyy}.{mm}.01.tif',
                        lai_path = r'C:\LeafAreaIndex\LAI_{yyyy}{mm}.tif',
                        swi_path = r'C:\Soil Moisture\MonthlyMean\SWI_{yyyy}{mm}.tif',
                        swio_path = r'C:\Soil Moisture\FirstDay\SWI_{yyyy}{mm}.tif',
                        swix_path = r'C:\Soil Moisture\LastDay\SWI_{yyyy}{mm}.tif',
                        qratio_path = r'C:\Runoff Ratio\Qr_{yyyy}.tif',
                        rainydays_path = r'C:\Rainy days\chirps-v2.0.{yyyy}.{mm}_rainydays.tif',
                        thetasat_ras = r'C:\Saturated water content\wcsat_topsoil.tif',
                        rootdepth_ras = r'C:\Root depth\rd_mm.tif',
                        input_nc = r'C:\input_file_basin_A.nc')

# Run WaterPix
input_nc = r'C:\input_file_basin_A.nc'
output_nc=r'C:\output_file_basin_A.nc'
wp_gdal.run(input_nc, output_nc)

# Export rasters
output_path = r'C:\output_rasters'
wp_gdal.output_nc_to_tiffs(output_nc, output_path)

Citation

Espinoza-Dávalos, G. E., & Bastiaanssen, W. G. M. (2017). WaterPix: A Data Based Water Balance Model for Water Accounting. http://doi.org/10.5281/zenodo.1045574

Contact

Gonzalo E. Espinoza, PhD, MSc
Integrated Water Systems and Governance
IHE Delft Institute for Water Education
T: +31 15 2152313
E: g.espinoza@un-ihe.org
I: un-ihe.org | wateraccounting.org | gespinoza.org