pycraf 0.24.2

# Introduction #

• Version: 0.24

• Authors: Benjamin Winkel

[](https://pypi.python.org/pypi/pycraf) [](https://travis-ci.org/bwinkel/pycraf) [](https://ci.appveyor.com/project/bwinkel/pycraf) [](https://www.github.com/bwinkel/pycraf/blob/master/COPYING) [](https://coveralls.io/github/bwinkel/pycraf?branch=master) [](http://pycraf.readthedocs.io/en/latest/)

# Disclaimer # pycraf is still in the early-development stage. While much of the functionality is already working as intended, the API is not yet stable. Nevertheless, we kindly invite you to use and test the library and we are grateful for feedback. Note, that the documentation is still missing (but at least docstrings are provided).

# Purpose #

pycraf is a Python package that provides functions and procedures for various tasks in spectrum-management compatibility studies. A typical example would be to calculate the interference levels at a radio telescope produced from a ratio broadcasting tower.

# Features #

• Full implementation of [ITU-R Rec. P.452-16](https://www.itu.int/rec/R-REC-P.452-16-201507-I/en) that allows to calculate path attenuation for the distance between interferer and victim service. Supports to load NASA’s [Shuttle Radar Topography Mission (SRTM)](https://www2.jpl.nasa.gov/srtm/) data for height-profile generation.

• Full implementation of [ITU-R Rec. P.676-10](https://www.itu.int/rec/R-REC-P.676-10-201309-S/en), which provides two atmospheric models to calculate the attenuation for paths through Earth’s atmosphere.

• Provides various antenna patterns necessary for compatibility studies (e.g., RAS, IMT, fixed-service links).

• Functions to convert power flux densities, field strengths, transmitted and received powers at certain distances and frequencies into each other.

# License #

pycraf is published under GPL v3, an open-source license.

For some of the functionality provided in pycraf, data files provided by the ITU are necessary. For example, the atmospheric model in the pycraf.atm subpackage implements the algorithm described in [ITU-R Recommendation P.676](https://www.itu.int/rec/R-REC-P.676-10-201309-S/en). Annex 1 of this Recommendation makes use of spectroscopic information of the oxygen and water vapour lines given in Tables 1 and 2 of P.676.

ITU kindly gave us permission to include data files into pycraf that are distributed with the Recommendations on the ITU servers. This makes it possible to just use pycraf without the need to manually download necessary data files. However, these data files are not free for commercial use. For details, please see the [LICENSE.ITU](https://www.github.com/bwinkel/pycraf/blob/master/LICENSE.ITU) file.

We are very grateful for the kind support from ITU study groups and ITU’s legal department.

# Installation #

The easiest way to install pycraf is via pip:

` pip install pycraf `

The installation is also possible from source. Download the tar.gz-file, extract (or clone from GitHub) and simply execute

` python setup.py install `

## Dependencies ##

We kept the dependencies as minimal as possible. The following packages are required: * numpy 1.8 or later * astropy 1.1 or later * pyproj 1.9 or later

## Windows machines ##

Note, for Windows machines we provide a binary wheel (Python 3.5+ only). However, the pyproj package is a dependency and unfortunately, the official pyproj repository on PyPI contains only the sources. You can download a suitable wheel from [Christoph Gohlke’s package site](http://www.lfd.uci.edu/~gohlke/pythonlibs/#pyproj). Then use

` pip install [path-to-wheel]\pyproj‑*.whl `

If you’re using [Anaconda](https://www.continuum.io/downloads) (recommended), it is much simpler: ` conda install -c conda-forge pyproj `

## SRTM data ##

To make full use of the path attenuation calculations provided by pycraf (implements [ITU-R Rec. P.452](https://www.itu.int/rec/R-REC-P.452-16-201507-I/en)), we recommend to use NASA’s [Shuttle Radar Topography Mission (SRTM)](https://www2.jpl.nasa.gov/srtm/) data for height- profile generation. pycraf can work with so-called .hgt files, a very simple binary format. Each .hgt file, a so-called tile, just contains 1201x1201 16-bit integers. From the file naming scheme, one can infer the associated coordinates. Most tiles contain one square-degree.

Unfortunately, we cannot provide SRTM data as part of the package, due to the large file sizes and legal reasons. But once you downloaded the necessary tiles (all or only a subset appropriate for your region), simply define the environment variable $SRTMDATA, let it point to the folder containing the tiles, and pycraf will find the files when it is imported from Python.

# Usage #

## Examples and Documentation ##

Will follow asap. Sorry for the inconvenience! You can find tutorials in the [notebooks](http://nbviewer.jupyter.org/github/bwinkel/pycraf/blob/master/notebooks/) directory on the pycraf repository.

# Who do I talk to? #

If you encounter any problems or have questions, do not hesitate to raise an issue or make a pull request. Moreover, you can contact the devs directly:

• <bwinkel@mpifr.de>