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Merge pull request #22 from sjoro/vii
Add VII interpolator.
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‎AUTHORS.md‎

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# Project Contributors
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The following people have made contributions to this project:
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<!--- Use your GitHub account or any other personal reference URL --->
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<!--- If you wish to not use your real name, please use your github username --->
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<!--- The list should be alphabetical by last name if possible, with github usernames at the bottom --->
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<!--- See https://gist.github.com/djhoese/52220272ec73b12eb8f4a29709be110d for auto-generating parts of this list --->
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- [Amit Aronovitch (AmitAronovitch)](https://github.com/AmitAronovitch)
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- [Adam Dybbroe (adybbroe)](https://github.com/adybbroe)
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- [Rolf Helge Pfeiffer (HelgeDMI)](https://github.com/HelgeDMI)
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- [David Hoese (djhoese)](https://github.com/djhoese)
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- [Mikhail Itkin (mitkin)](https://github.com/mitkin)
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- [Sauli Joro (sjoro)](https://github.com/sjoro)
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- [Panu Lahtinen (pnuu)](https://github.com/pnuu)
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- [Martin Raspaud (mraspaud)](https://github.com/mraspaud)

‎geotiepoints/tests/test_viiinterpolator.py‎

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#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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# Copyright (c) 2017-2020 Python-geotiepoints developers
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#
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# This file is part of python-geotiepoints.
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#
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# python-geotiepoints is free software: you can redistribute it and/or modify it under the
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# terms of the GNU General Public License as published by the Free Software
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# Foundation, either version 3 of the License, or (at your option) any later
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# version.
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#
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# python-geotiepoints is distributed in the hope that it will be useful, but WITHOUT ANY
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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# A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along with
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# python-geotiepoints. If not, see <http://www.gnu.org/licenses/>.
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"""Test of the interpolation of geographical tiepoints for the VII products.
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It follows the description provided in document "EPS-SG VII Level 1B Product Format Specification".
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"""
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import unittest
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import numpy as np
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import xarray as xr
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from geotiepoints.viiinterpolator import tie_points_interpolation, tie_points_geo_interpolation
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TEST_N_SCANS = 2
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TEST_TIE_POINTS_FACTOR = 2
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TEST_SCAN_ALT_TIE_POINTS = 3
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TEST_VALID_ALT_TIE_POINTS = TEST_SCAN_ALT_TIE_POINTS * TEST_N_SCANS
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TEST_INVALID_ALT_TIE_POINTS = TEST_SCAN_ALT_TIE_POINTS * TEST_N_SCANS + 1
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TEST_ACT_TIE_POINTS = 4
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# Results of latitude/longitude interpolation with simple interpolation on coordinates
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TEST_LON_1 = np.array(
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[[-12., -11.5, -11., -10.5, -9., -8.5, -8., -7.5],
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[-9., -8.5, -8., -7.5, -6., -5.5, -5., -4.5],
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[-6., -5.5, -5., -4.5, -3., -2.5, -2., -1.5],
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[-3., -2.5, -2., -1.5, 0., 0.5, 1., 1.5],
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[0., 0.5, 1., 1.5, 3., 3.5, 4., 4.5],
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[3., 3.5, 4., 4.5, 6., 6.5, 7., 7.5]]
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)
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TEST_LAT_1 = np.array(
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[[0., 0.5, 1., 1.5, 3., 3.5, 4., 4.5],
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[3., 3.5, 4., 4.5, 6., 6.5, 7., 7.5],
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[6., 6.5, 7., 7.5, 9., 9.5, 10., 10.5],
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[9., 9.5, 10., 10.5, 12., 12.5, 13., 13.5],
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[12., 12.5, 13., 13.5, 15., 15.5, 16., 16.5],
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[15., 15.5, 16., 16.5, 18., 18.5, 19., 19.5]]
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)
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# Results of latitude/longitude interpolation on cartesian coordinates (latitude above 60 degrees)
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TEST_LON_2 = np.array(
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[[-12., -11.50003808, -11., -10.50011426, -9., -8.50026689, -8., -7.50034342],
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[-9.00824726, -8.50989187, -8.01100418, -7.51272848, -6.01653996, -5.51842688, -5.01932226, -4.52129225],
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[-6., -5.50049716, -5., -4.50057447, -3., -2.50073021, -2., -1.50080874],
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[-3.02492451, -2.52706443, -2.02774808, -1.52997501, -0.03344942, 0.46414517, 0.96366893, 1.4611719],
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[0., 0.49903263, 1., 1.49895241, 3., 3.49878988, 4., 4.49870746],
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[2.9578336, 3.45514812, 3.9548757, 4.4520932, 5.94886832, 6.44588569, 6.94581415, 7.44272818]]
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)
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TEST_LAT_2 = np.array(
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[[0., 0.49998096, 1., 1.49994287, 3., 3.49986656, 4., 4.4998283],
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[2.99588485, 3.49506416, 3.99450923, 4.49364876, 5.99174708, 6.49080542, 6.99035883, 7.4893757],
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[6., 6.49975143, 7., 7.49971278, 9., 9.49963492, 10., 10.49959566],
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[8.98756357, 9.48649563, 9.98615477, 10.4850434, 11.98331018, 12.48210974, 12.98187246, 13.4806263],
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[12., 12.49951634, 13., 13.49947623, 15., 15.49939498, 16., 16.49935377],
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[14.97896116, 15.47762097, 15.97748548, 16.47609689, 17.97448854, 18.47300011, 18.97296495, 19.47142496]]
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)
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# Results of latitude/longitude interpolation on cartesian coordinates (longitude with a 360 degrees step)
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TEST_LON_3 = np.array(
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[[-12., -11.50444038, -11., -10.50459822, -9., -8.50493209, -8., -7.50510905],
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[-9.17477341, -8.68280267, -8.18102962, -7.68936161, -6.19433153, -5.70332248, -5.20141997, -4.71077058],
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[-6., -5.50548573, -5., -4.50568668, -3., -2.50611746, -2., -1.506349],
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[-3.2165963, -2.72673687, -2.22474246, -1.73531828, -0.24232275, 0.24613534, 0.7481615, 1.23608137],
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[0., 0.49315061, 1., 1.49287934, 3., 3.49228746, 4., 4.49196335],
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[2.72743411, 3.21414435, 3.71610443, 4.20213182, 5.69115252, 6.17562189, 6.67735289, 7.16092853]]
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)
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TEST_LAT_3 = np.array(
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[[45., 45.49777998, 46., 46.49770107, 48., 48.49753416, 49., 49.49744569],
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[47.91286617, 48.40886652, 48.90975264, 49.40560282, 50.90313463, 51.39865815, 51.8996091, 52.39495445],
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[51., 51.49725738, 52., 52.49715691, 54., 54.50311196, 55., 55.50299846],
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[54.11364234, 54.61463583, 55.10950687, 55.61043728, 57.10152529, 57.60232834, 58.09766771, 58.59840655],
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[57., 57.50277937, 58., 58.50267347, 60., 60.50246826, 61., 61.5023687],
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[60.09019289, 60.59080228, 61.0865661, 61.58711028, 63.07951189, 63.57992468, 64.07607638, 64.57642295]]
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)
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class TestViiInterpolator(unittest.TestCase):
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"""Test the vii_utils module."""
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def setUp(self):
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"""Set up the test."""
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# Create the arrays for the interpolation test
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# The first has a valid number of n_tie_alt points (multiple of SCAN_ALT_TIE_POINTS)
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self.valid_data_for_interpolation = xr.DataArray(
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np.arange(
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TEST_VALID_ALT_TIE_POINTS * TEST_ACT_TIE_POINTS,
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dtype=np.float64,
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).reshape(TEST_ACT_TIE_POINTS, TEST_VALID_ALT_TIE_POINTS),
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dims=('num_tie_points_act', 'num_tie_points_alt'),
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)
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# The second has an invalid number of n_tie_alt points (not multiple of SCAN_ALT_TIE_POINTS)
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self.invalid_data_for_interpolation = xr.DataArray(
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np.arange(
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TEST_INVALID_ALT_TIE_POINTS * TEST_ACT_TIE_POINTS,
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dtype=np.float64,
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).reshape(TEST_ACT_TIE_POINTS, TEST_INVALID_ALT_TIE_POINTS),
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dims=('num_tie_points_act', 'num_tie_points_alt'),
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)
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# Then two arrays containing valid longitude and latitude data
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self.longitude = xr.DataArray(
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np.linspace(
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-12,
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11,
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num=TEST_VALID_ALT_TIE_POINTS * TEST_ACT_TIE_POINTS,
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dtype=np.float64,
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).reshape(TEST_ACT_TIE_POINTS, TEST_VALID_ALT_TIE_POINTS),
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dims=('num_tie_points_act', 'num_tie_points_alt'),
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)
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self.latitude = xr.DataArray(
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np.linspace(
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0,
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23,
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num=TEST_VALID_ALT_TIE_POINTS * TEST_ACT_TIE_POINTS,
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dtype=np.float64,
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).reshape(TEST_ACT_TIE_POINTS, TEST_VALID_ALT_TIE_POINTS),
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dims=('num_tie_points_act', 'num_tie_points_alt'),
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)
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# Then one containing latitude data above 60 degrees
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self.latitude_over60 = xr.DataArray(
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np.linspace(
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45,
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68,
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num=TEST_VALID_ALT_TIE_POINTS * TEST_ACT_TIE_POINTS,
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dtype=np.float64,
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).reshape(TEST_ACT_TIE_POINTS, TEST_VALID_ALT_TIE_POINTS),
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dims=('num_tie_points_act', 'num_tie_points_alt'),
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)
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# Then one containing longitude data with a 360 degrees step
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self.longitude_over360 = xr.DataArray(
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np.linspace(
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-12,
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11,
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num=TEST_VALID_ALT_TIE_POINTS * TEST_ACT_TIE_POINTS,
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dtype=np.float64,
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).reshape(TEST_ACT_TIE_POINTS, TEST_VALID_ALT_TIE_POINTS) % 360.,
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dims=('num_tie_points_act', 'num_tie_points_alt'),
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)
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def tearDown(self):
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"""Tear down the test."""
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# Nothing to do
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pass
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def test_tie_points_interpolation(self):
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"""# Test the interpolation routine with valid and invalid input."""
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# Test the interpolation routine with valid input
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result_valid = tie_points_interpolation(
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[self.valid_data_for_interpolation],
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TEST_SCAN_ALT_TIE_POINTS,
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TEST_TIE_POINTS_FACTOR
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)[0]
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act_points_interp = (TEST_ACT_TIE_POINTS - 1) * TEST_TIE_POINTS_FACTOR
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num_scans = TEST_VALID_ALT_TIE_POINTS // TEST_SCAN_ALT_TIE_POINTS
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scan_alt_points_interp = (TEST_SCAN_ALT_TIE_POINTS - 1) * TEST_TIE_POINTS_FACTOR
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# It is easier to check the delta between interpolated points, which must be 1/8 of the original delta
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# Across the track, it is possible to check the delta on the entire array
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delta_axis_0 = 1.0 * TEST_VALID_ALT_TIE_POINTS / TEST_TIE_POINTS_FACTOR
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self.assertTrue(np.allclose(
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np.diff(result_valid, axis=0),
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np.ones((act_points_interp - 1, num_scans * scan_alt_points_interp)) * delta_axis_0
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))
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delta_axis_1 = 1.0 / TEST_TIE_POINTS_FACTOR
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# Along the track, it is necessary to check the delta on each scan separately
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for i in range(num_scans):
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first_index = i*(TEST_SCAN_ALT_TIE_POINTS-1)*TEST_TIE_POINTS_FACTOR
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last_index = (i+1)*(TEST_SCAN_ALT_TIE_POINTS-1)*TEST_TIE_POINTS_FACTOR
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result_per_scan = result_valid[:, first_index:last_index]
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self.assertTrue(np.allclose(
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np.diff(result_per_scan, axis=1),
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np.ones((act_points_interp, (TEST_SCAN_ALT_TIE_POINTS-1)*TEST_TIE_POINTS_FACTOR - 1)) * delta_axis_1
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))
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self.assertEqual(len(result_valid.coords), 0)
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# Test the interpolation routine with invalid input
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with self.assertRaises(ValueError):
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tie_points_interpolation(
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[self.invalid_data_for_interpolation],
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TEST_SCAN_ALT_TIE_POINTS,
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TEST_TIE_POINTS_FACTOR
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)[0]
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def test_tie_points_geo_interpolation(self):
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"""# Test the coordinates interpolation routine with valid and invalid input."""
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# Test the interpolation routine with valid input
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lon, lat = tie_points_geo_interpolation(
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self.longitude,
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self.latitude,
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TEST_SCAN_ALT_TIE_POINTS,
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TEST_TIE_POINTS_FACTOR
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)
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self.assertTrue(np.allclose(lon, TEST_LON_1))
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self.assertTrue(np.allclose(lat, TEST_LAT_1))
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lon, lat = tie_points_geo_interpolation(
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self.longitude_over360,
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self.latitude,
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TEST_SCAN_ALT_TIE_POINTS,
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TEST_TIE_POINTS_FACTOR
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)
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self.assertTrue(np.allclose(lon, TEST_LON_2))
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self.assertTrue(np.allclose(lat, TEST_LAT_2))
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lon, lat = tie_points_geo_interpolation(
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self.longitude,
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self.latitude_over60,
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TEST_SCAN_ALT_TIE_POINTS,
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TEST_TIE_POINTS_FACTOR
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)
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self.assertTrue(np.allclose(lon, TEST_LON_3))
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self.assertTrue(np.allclose(lat, TEST_LAT_3))
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# Test the interpolation routine with invalid input (different dimensions of the two arrays)
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with self.assertRaises(ValueError):
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tie_points_geo_interpolation(
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self.longitude,
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self.invalid_data_for_interpolation,
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TEST_SCAN_ALT_TIE_POINTS,
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TEST_TIE_POINTS_FACTOR
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)
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def suite():
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"""The suite for VII interpolator"""
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loader = unittest.TestLoader()
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mysuite = unittest.TestSuite()
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mysuite.addTest(loader.loadTestsFromTestCase(TestViiInterpolator))
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return mysuite
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if __name__ == "__main__":
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unittest.main()

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