Coverage for tests/test_HealpixPixelization.py: 20%

1# This file is part of sphgeom. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (http://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This software is dual licensed under the GNU General Public License and also 

10# under a 3-clause BSD license. Recipients may choose which of these licenses 

11# to use; please see the files gpl-3.0.txt and/or bsd_license.txt, 

12# respectively. If you choose the GPL option then the following text applies 

13# (but note that there is still no warranty even if you opt for BSD instead): 

14# 

15# This program is free software: you can redistribute it and/or modify 

16# it under the terms of the GNU General Public License as published by 

17# the Free Software Foundation, either version 3 of the License, or 

18# (at your option) any later version. 

19# 

20# This program is distributed in the hope that it will be useful, 

21# but WITHOUT ANY WARRANTY; without even the implied warranty of 

22# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

23# GNU General Public License for more details. 

24# 

25# You should have received a copy of the GNU General Public License 

26# along with this program. If not, see <http://www.gnu.org/licenses/>. 

27 

28import pickle 

29import unittest 

30 

31import hpgeom as hpg 

32import numpy as np 

33 

34try: 

35 import yaml 

36except ImportError: 

37 yaml = None 

38 

39from lsst.sphgeom import Angle, Box, Circle, ConvexPolygon, Ellipse, HealpixPixelization, LonLat, UnitVector3d 

40 

41 

42class HealpixPixelizationTestCase(unittest.TestCase): 

43 """Test HEALPix pixelization.""" 

44 

45 def test_construction(self): 

46 """Test construction of a HealpixPixelization.""" 

47 with self.assertRaises(ValueError): 

48 HealpixPixelization(-1) 

49 h1 = HealpixPixelization(5) 

50 self.assertEqual(h1.level, 5) 

51 self.assertEqual(h1.getLevel(), 5) 

52 self.assertEqual(h1.nside, 32) 

53 h2 = HealpixPixelization(6) 

54 h3 = HealpixPixelization(h2.level) 

55 self.assertNotEqual(h1, h2) 

56 self.assertEqual(h2, h3) 

57 

58 def test_indexing(self): 

59 """Test indexing of HealpixPixelization.""" 

60 h = HealpixPixelization(5) 

61 vec = UnitVector3d(1, 1, 1) 

62 lonlat = LonLat(vec) 

63 pix = hpg.angle_to_pixel(h.nside, lonlat.getLon().asDegrees(), lonlat.getLat().asDegrees()) 

64 self.assertEqual(h.index(UnitVector3d(1, 1, 1)), pix) 

65 

66 def test_pixel(self): 

67 """Test pixel polygon of HealpixPixelization.""" 

68 h = HealpixPixelization(5) 

69 pix_poly = h.pixel(10) 

70 self.assertIsInstance(pix_poly, ConvexPolygon) 

71 

72 def test_envelope(self): 

73 """Test envelope method of HealpixPixelization.""" 

74 # Make the hardest intersection: a region that _just_ 

75 # touches a healpix pixel. 

76 h = HealpixPixelization(5) 

77 pix = hpg.angle_to_pixel(h.nside, 50.0, 20.0) 

78 

79 corners_ra, corners_dec = hpg.boundaries(h.nside, pix, step=1) 

80 

81 # Take the southernmost corner... 

82 smost = np.argmin(corners_dec) 

83 

84 # Choose challenging comparison box corners: 

85 ra_range = np.array([corners_ra[smost] - 0.5, corners_ra[smost] + 0.5]) 

86 dec_range = np.array([corners_dec[smost] - 0.5, corners_dec[smost] + 1e-8]) 

87 

88 # Test the box region 

89 box = Box( 

90 point1=LonLat.fromDegrees(ra_range[0], dec_range[0]), 

91 point2=LonLat.fromDegrees(ra_range[1], dec_range[1]), 

92 ) 

93 # These pixels have been checked to completely overlap the region 

94 self._check_envelope(h, box, [98, 99, 104, 105]) 

95 

96 # Try a polygon region: 

97 poly = ConvexPolygon( 

98 [ 

99 UnitVector3d(LonLat.fromDegrees(ra_range[0], dec_range[0])), 

100 UnitVector3d(LonLat.fromDegrees(ra_range[1], dec_range[0])), 

101 UnitVector3d(LonLat.fromDegrees(ra_range[1], dec_range[1])), 

102 UnitVector3d(LonLat.fromDegrees(ra_range[0], dec_range[1])), 

103 UnitVector3d(LonLat.fromDegrees(ra_range[0], dec_range[0])), 

104 ] 

105 ) 

106 self._check_envelope(h, poly, [98, 99, 104, 105]) 

107 

108 # Try a circle region 

109 circle = Circle( 

110 center=UnitVector3d( 

111 LonLat.fromDegrees((ra_range[0] + ra_range[1]) / 2.0, (dec_range[0] + dec_range[1]) / 2.0) 

112 ), 

113 angle=Angle.fromDegrees((dec_range[1] - dec_range[0]) / 2.0), 

114 ) 

115 self._check_envelope(h, circle, [98, 99, 104, 105]) 

116 

117 # Try a circle region with zero-radius (representing a point) 

118 pt_circle = Circle( 

119 center=UnitVector3d( 

120 LonLat.fromDegrees((ra_range[0] + ra_range[1]) / 2.0, (dec_range[0] + dec_range[1]) / 2.0) 

121 ), 

122 ) 

123 self._check_envelope(h, pt_circle, [98]) 

124 

125 def test_envelope_missing_neighbors(self): 

126 """Test envelope, with a pixel with missing neighbors. 

127 

128 Testing DM-47043. 

129 """ 

130 h = HealpixPixelization(0) 

131 h_highres = HealpixPixelization(4) 

132 

133 self.assertEqual(h._nside_highres, h_highres._nside) 

134 

135 # Find a pixel with a missing neighbor at high res. 

136 n = hpg.neighbors(h_highres._nside, np.arange(hpg.nside_to_npixel(h_highres._nside))) 

137 ind = np.argmin(n) 

138 self.assertEqual(n.ravel()[ind], -1) 

139 

140 # This is the pixel with a bad (-1) neighbor. 

141 badpix = ind // 8 

142 ra, dec = hpg.pixel_to_angle(h_highres._nside, badpix) 

143 

144 box = Box( 

145 point1=LonLat.fromDegrees(ra - 0.1, dec - 0.1), 

146 point2=LonLat.fromDegrees(ra + 0.1, dec + 0.1), 

147 ) 

148 

149 self._check_envelope(h, box, [0, 1, 5]) 

150 

151 def _check_envelope(self, pixelization, region, check_pixels): 

152 """Check the envelope from a region. 

153 

154 Parameters 

155 ---------- 

156 pixelization : `lsst.sphgeom.HealpixPixelization` 

157 region : `lsst.sphgeom.Region` 

158 check_pixels : `list` [`int`] 

159 """ 

160 pixel_range = pixelization.envelope(region) 

161 

162 pixels = [] 

163 for r in pixel_range.ranges(): 

164 pixels.extend(range(r[0], r[1])) 

165 

166 self.assertEqual(pixels, check_pixels) 

167 

168 def test_interior(self): 

169 """Test interior method of HealpixPixelization.""" 

170 h = HealpixPixelization(5) 

171 pix = hpg.angle_to_pixel(h.nside, 50.0, 20.0) 

172 

173 corners_ra, corners_dec = hpg.boundaries(h.nside, pix, step=1) 

174 

175 ra_range = np.array([corners_ra.min() - 1.0, corners_ra.max() + 1.0]) 

176 dec_range = np.array([corners_dec.min() - 1.0, corners_dec.max() + 1.0]) 

177 

178 # Test the box region 

179 box = Box( 

180 point1=LonLat.fromDegrees(ra_range[0], dec_range[0]), 

181 point2=LonLat.fromDegrees(ra_range[1], dec_range[1]), 

182 ) 

183 # These pixels have been checked to completely overlap the region 

184 self._check_interior(h, box, [pix]) 

185 

186 # Try a polygon region: 

187 poly = ConvexPolygon( 

188 [ 

189 UnitVector3d(LonLat.fromDegrees(ra_range[0], dec_range[0])), 

190 UnitVector3d(LonLat.fromDegrees(ra_range[1], dec_range[0])), 

191 UnitVector3d(LonLat.fromDegrees(ra_range[1], dec_range[1])), 

192 UnitVector3d(LonLat.fromDegrees(ra_range[0], dec_range[1])), 

193 UnitVector3d(LonLat.fromDegrees(ra_range[0], dec_range[0])), 

194 ] 

195 ) 

196 self._check_interior(h, poly, [pix]) 

197 

198 # Try a circle region 

199 circle = Circle( 

200 center=UnitVector3d( 

201 LonLat.fromDegrees((ra_range[0] + ra_range[1]) / 2.0, (dec_range[0] + dec_range[1]) / 2.0) 

202 ), 

203 angle=Angle.fromDegrees(2.5), 

204 ) 

205 self._check_interior(h, circle, [pix]) 

206 

207 # Try an ellipse region 

208 ellipse = Ellipse( 

209 center=UnitVector3d( 

210 LonLat.fromDegrees((ra_range[0] + ra_range[1]) / 2.0, (dec_range[0] + dec_range[1]) / 2.0) 

211 ), 

212 alpha=Angle.fromDegrees(1.5), 

213 beta=Angle.fromDegrees(2.5), 

214 orientation=Angle.fromDegrees(45.0), 

215 ) 

216 self._check_interior(h, ellipse, [pix]) 

217 

218 def _check_interior(self, pixelization, region, check_pixels): 

219 """Check the interior from a region. 

220 

221 Parameters 

222 ---------- 

223 pixelization : `lsst.sphgeom.HealpixPixelization` 

224 region : `lsst.sphgeom.Region` 

225 check_pixels : `list` [`int`] 

226 """ 

227 pixel_range = pixelization.interior(region) 

228 

229 pixels = [] 

230 for r in pixel_range.ranges(): 

231 pixels.extend(range(r[0], r[1])) 

232 

233 self.assertEqual(pixels, check_pixels) 

234 

235 def test_index_to_string(self): 

236 """Test converting index to string of HealpixPixelization.""" 

237 h = HealpixPixelization(5) 

238 self.assertEqual(h.toString(0), str(0)) 

239 self.assertEqual(h.toString(100), str(100)) 

240 

241 def test_string(self): 

242 """Test string representation of HealpixPixelization.""" 

243 h = HealpixPixelization(5) 

244 self.assertEqual(str(h), "HealpixPixelization(5)") 

245 self.assertEqual(str(h), repr(h)) 

246 self.assertEqual(h, eval(repr(h), {"HealpixPixelization": HealpixPixelization})) 

247 

248 def test_pickle(self): 

249 """Test pickling of HealpixPixelization.""" 

250 a = HealpixPixelization(5) 

251 b = pickle.loads(pickle.dumps(a)) 

252 self.assertEqual(a, b) 

253 

254 @unittest.skipIf(not yaml, "YAML module can not be imported") 

255 def test_yaml(self): 

256 """Test yaml representation of HealpixPixelization.""" 

257 a = HealpixPixelization(5) 

258 b = yaml.safe_load(yaml.dump(a)) 

259 self.assertEqual(a, b) 

260 

261 

262if __name__ == "__main__": 

263 unittest.main()