NSIDC坐标转换软件

 # NSIDC Polar Stereographic Projection lon/lat conversion: polar_convert Python functions for converting polar stereographic coordinates. This repository contains conversion functions between longitude/latitude and generic x, y (km) coordinates. There are also conversion functions between longitude/latitude and i, j grid coordinates for specific datasets for AMSR-E and SSM/I. ## Level of Support This repository is fully supported by NSIDC. If you discover any problems or bugs, please submit an Issue. If you would like to contribute to this repository, you may fork the repository and submit a pull request. See the [LICENSE](LICENSE) for details on permissions and warranties. Please contact nsidc@nsidc.org for more information. ## Requirements * Python 3.6 or higher (tested with 3.6.7 and 3.9.7) * [`numpy`](https://numpy.org/) (python library) These requirements are also included in the provided `environment.yml` file, which can be used with [conda](https://docs.conda.io/en/latest/) to install the requirements into a `conda` environment. ## Installation To install `polarstereo-lonlat-convert-py`, clone this repo and then run: ``` pip install --editable /path/to/cloned/polarstereo-lonlat-convert-py ``` This will install the `polar_convert` package in an 'editable' development mode, allowing you to make changes to the source code in `/path/to/cloned/polarstereo-lonlat-convert-py`. See [pip's documentation](https://pip.pypa.io/en/stable/cli/pip_install/#install-editable) for more information. ## Usage See the docstrings for individual functions in [`polar_convert.py`](./polar_convert/polar_convert.py) for details. The functions defined in this file can be used in your own projects. ### `polar_lonlat_to_xy` Convert from geodetic longitude and latitude to Polar Stereographic (X, Y) coordinates in km. Functional equivilient of [`mapll.for`](https://github.com/nsidc/polarstereo-latlon-convert-fortran/blob/main/locate/mapll.for). ``` >>> from polar_convert.constants import NORTH >>> from polar_convert import polar_lonlat_to_xy >>> longitude = 20 # longitude in degrees >>> latitude = 80 # latitude in degrees >>> true_scale_lat = 70 # true-scale latitude in degrees >>> re = 6378.137 # earth radius in km >>> e = 0.01671 # earth eccentricity >>> hemisphere = NORTH >>> polar_lonlat_to_xy(longitude, latitude, true_scale_lat, re, e, hemisphere) [370.2450347527368, -1017.2398726483362] ``` ### `polar_xy_to_lonlat` Convert from Polar Stereographic (x, y) coordinates to geodetic longitude and latitude. Functional equivilent of [`mapxy.for`](https://github.com/nsidc/polarstereo-latlon-convert-fortran/blob/main/locate/mapxy.for). ``` >>> from polar_convert.constants import NORTH >>> from polar_convert import polar_xy_to_lonlat >>> x = 370.25 # x coordinate in km >>> y = -1017.24 # y coordinate in km >>> true_scale_lat = 70 # true-scale latitude in degrees >>> re = 6378.137 # earth radius in km >>> e = 0.01671 # earth eccentricity >>> hemisphere = NORTH >>> polar_xy_to_lonlat(x, y, true_scale_lat, re, e, hemisphere) [20.000244645773623, 79.99998329186566] ``` ### `polar_lonlat_to_ij` Convert from longitude and latitude to NSIDC Polar Stereographic I, J (grid) coordinates. ``` >>> from polar_convert.constants import NORTH >>> from polar_convert import polar_lonlat_to_ij >>> longitude = 45 # longitude in degrees >>> latitude = 85 # latitude in degrees >>> grid_size = 6.25 # in km >>> hemisphere = NORTH >>> polar_lonlat_to_ij(longitude, latitude, grid, hemisphere) [703, 936] ``` ### `polar_ij_to_lonlat` Convert from NSIDC Polar Stereographic I, J (grid) coordinates to longitude and latitude. ``` >>> from polar_convert.constants import NORTH >>> from polar_convert import polar_ij_to_lonlat >>> i = 10 # `i` is an int representing the x grid coordinate >>> j = 200 # `j` is an int representing y grid coordinate >>> grid_size = 12.5 # in km >>> hemisphere = NORTH >>> polar_ij_to_lonlat(i, j, grid, hemisphere) [183.02869857834057, 45.89915728375587] ``` ## Development See [DEVELOPMENT.md](./DEVELOPMENT.md) for information on how to contribute to this python code. ## License See [LICENSE](LICENSE), unless otherwise stated in the README file with each subdirectory. ## Code of Conduct See [Code of Conduct](CODE_OF_CONDUCT.md). ## Credit This software was developed by the NASA National Snow and Ice Data Center Distributed Active Archive Center. Author: Chris Torrence, September 2019