Coverage for tests/test_HealpixPixelization.py: 21%

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2# LSST Data Management System 

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21# 

22import pickle 

23import unittest 

24 

25import hpgeom as hpg 

26import numpy as np 

27 

28try: 

29 import yaml 

30except ImportError: 

31 yaml = None 

32 

33from lsst.sphgeom import Angle, Box, Circle, ConvexPolygon, Ellipse, HealpixPixelization, LonLat, UnitVector3d 

34 

35 

36class HealpixPixelizationTestCase(unittest.TestCase): 

37 """Test HEALPix pixelization.""" 

38 

39 def test_construction(self): 

40 """Test construction of a HealpixPixelization.""" 

41 with self.assertRaises(ValueError): 

42 HealpixPixelization(-1) 

43 h1 = HealpixPixelization(5) 

44 self.assertEqual(h1.level, 5) 

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

46 self.assertEqual(h1.nside, 32) 

47 h2 = HealpixPixelization(6) 

48 h3 = HealpixPixelization(h2.level) 

49 self.assertNotEqual(h1, h2) 

50 self.assertEqual(h2, h3) 

51 

52 def test_indexing(self): 

53 """Test indexing of HealpixPixelization.""" 

54 h = HealpixPixelization(5) 

55 vec = UnitVector3d(1, 1, 1) 

56 lonlat = LonLat(vec) 

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

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

59 

60 def test_pixel(self): 

61 """Test pixel polygon of HealpixPixelization.""" 

62 h = HealpixPixelization(5) 

63 pix_poly = h.pixel(10) 

64 self.assertIsInstance(pix_poly, ConvexPolygon) 

65 

66 def test_envelope(self): 

67 """Test envelope method of HealpixPixelization.""" 

68 # Make the hardest intersection: a region that _just_ 

69 # touches a healpix pixel. 

70 h = HealpixPixelization(5) 

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

72 

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

74 

75 # Take the southernmost corner... 

76 smost = np.argmin(corners_dec) 

77 

78 # Choose challenging comparison box corners: 

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

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

81 

82 # Test the box region 

83 box = Box( 

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

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

86 ) 

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

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

89 

90 # Try a polygon region: 

91 poly = ConvexPolygon( 

92 [ 

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

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

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

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

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

98 ] 

99 ) 

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

101 

102 # Try a circle region 

103 circle = Circle( 

104 center=UnitVector3d( 

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

106 ), 

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

108 ) 

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

110 

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

112 """Check the envelope from a region. 

113 

114 Parameters 

115 ---------- 

116 pixelization : `lsst.sphgeom.HealpixPixelization` 

117 region : `lsst.sphgeom.Region` 

118 check_pixels : `list` [`int`] 

119 """ 

120 pixel_range = pixelization.envelope(region) 

121 

122 pixels = [] 

123 for r in pixel_range.ranges(): 

124 pixels.extend(range(r[0], r[1])) 

125 

126 self.assertEqual(pixels, check_pixels) 

127 

128 def test_interior(self): 

129 """Test interior method of HealpixPixelization.""" 

130 h = HealpixPixelization(5) 

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

132 

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

134 

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

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

137 

138 # Test the box region 

139 box = Box( 

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

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

142 ) 

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

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

145 

146 # Try a polygon region: 

147 poly = ConvexPolygon( 

148 [ 

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

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

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

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

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

154 ] 

155 ) 

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

157 

158 # Try a circle region 

159 circle = Circle( 

160 center=UnitVector3d( 

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

162 ), 

163 angle=Angle.fromDegrees(2.5), 

164 ) 

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

166 

167 # Try an ellipse region 

168 ellipse = Ellipse( 

169 center=UnitVector3d( 

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

171 ), 

172 alpha=Angle.fromDegrees(1.5), 

173 beta=Angle.fromDegrees(2.5), 

174 orientation=Angle.fromDegrees(45.0), 

175 ) 

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

177 

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

179 """Check the interior from a region. 

180 

181 Parameters 

182 ---------- 

183 pixelization : `lsst.sphgeom.HealpixPixelization` 

184 region : `lsst.sphgeom.Region` 

185 check_pixels : `list` [`int`] 

186 """ 

187 pixel_range = pixelization.interior(region) 

188 

189 pixels = [] 

190 for r in pixel_range.ranges(): 

191 pixels.extend(range(r[0], r[1])) 

192 

193 self.assertEqual(pixels, check_pixels) 

194 

195 def test_index_to_string(self): 

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

197 h = HealpixPixelization(5) 

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

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

200 

201 def test_string(self): 

202 """Test string representation of HealpixPixelization.""" 

203 h = HealpixPixelization(5) 

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

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

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

207 

208 def test_pickle(self): 

209 """Test pickling of HealpixPixelization.""" 

210 a = HealpixPixelization(5) 

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

212 self.assertEqual(a, b) 

213 

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

215 def test_yaml(self): 

216 """Test yaml representation of HealpixPixelization.""" 

217 a = HealpixPixelization(5) 

218 b = yaml.safe_load(yaml.dump(a)) 

219 self.assertEqual(a, b) 

220 

221 

222if __name__ == "__main__": 

223 unittest.main()