Coverage for pygeodesy/elevations.py: 80%

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1 

2# -*- coding: utf-8 -*- 

3 

4u'''Web-services-based elevations and C{CONUS} geoid heights. 

5 

6Functions to obtain elevations and geoid heights thru web services, 

7for (lat, lon) locations, currently limited to the U{Conterminous 

8US (CONUS)<https://WikiPedia.org/wiki/Contiguous_United_States>}, 

9see also modules L{pygeodesy.geoids} and L{pygeodesy.heights} and 

10U{USGS10mElev.py<https://Gist.GitHub.com/pyRobShrk>}. 

11 

12@see: Module L{pygeodesy.geoids} to get geoid heights from other 

13 sources and for regions other than C{CONUS}. 

14 

15@note: If on B{macOS} an C{SSLCertVerificationError} occurs, like 

16 I{"[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: 

17 self "signed certificate in certificate chain ..."}, review 

18 U{this post<https://StackOverflow.com/questions/27835619/ 

19 urllib-and-ssl-certificate-verify-failed-error>} for a remedy. 

20 From a C{Terminal} window run: 

21 C{"/Applications/Python\\ X.Y/Install\\ Certificates.command"} 

22''' 

23 

24from pygeodesy.basics import clips, ub2str 

25from pygeodesy.errors import ParseError, _xkwds_get 

26from pygeodesy.interns import NN, _AMPERSAND_, _COLONSPACE_, \ 

27 _elevation_, _height_, _LCURLY_, \ 

28 _n_a_, _no_, _RCURLY_, _SPACE_ 

29from pygeodesy.lazily import _ALL_LAZY 

30from pygeodesy.named import _NamedTuple 

31from pygeodesy.streprs import fabs, Fmt, fstr, lrstrip 

32from pygeodesy.units import Lat, Lon, Meter, Scalar, Str 

33 

34# from math import fabs # from .karney 

35 

36__all__ = _ALL_LAZY.elevations 

37__version__ = '24.06.11' 

38 

39try: 

40 from urllib2 import urlopen # quote, urlcleanup 

41 from httplib import HTTPException as HTTPError 

42 

43except (ImportError, NameError): # Python 3+ 

44 from urllib.request import urlopen # urlcleanup 

45 # from urllib.parse import quote 

46 from urllib.error import HTTPError 

47 

48_JSON_ = 'JSON' 

49_QUESTION_ = '?' 

50_XML_ = 'XML' 

51 

52try: 

53 from json import loads as _json 

54except ImportError: 

55 

56 from pygeodesy.interns import _COMMA_, _QUOTE2_ 

57 _QUOTE2COLONSPACE_ = _QUOTE2_ + _COLONSPACE_ 

58 

59 def _json(ngs): 

60 '''(INTERNAL) Convert an NGS response in JSON to a C{dict}. 

61 ''' 

62 # b'{"geoidModel": "GEOID12A", 

63 # "station": "UserStation", 

64 # "lat": 37.8816, 

65 # "latDms": "N375253.76000", 

66 # "lon": -121.9142, 

67 # "lonDms": "W1215451.12000", 

68 # "geoidHeight": -31.703, 

69 # "error": 0.064 

70 # }' 

71 # 

72 # or in case of errors: 

73 # 

74 # b'{"error": "No suitable Geoid model found for model 15" 

75 # }' 

76 d = {} 

77 for t in lrstrip(ngs.strip(), lrpairs={_LCURLY_: _RCURLY_}).split(_COMMA_): 

78 t = t.strip() 

79 j = t.strip(_QUOTE2_).split(_QUOTE2COLONSPACE_) 

80 if len(j) != 2: 

81 raise ParseError(json=t) 

82 k, v = j 

83 try: 

84 v = float(v) 

85 except (TypeError, ValueError): 

86 v = Str(ub2str(v.lstrip().lstrip(_QUOTE2_)), name=k) 

87 d[k] = v 

88 return d 

89 

90 

91def _error(fun, lat, lon, e): 

92 '''(INTERNAL) Format an error 

93 ''' 

94 return _COLONSPACE_(Fmt.PAREN(fun.__name__, fstr((lat, lon))), e) 

95 

96 

97def _qURL(url, timeout=2, **params): 

98 '''(INTERNAL) Build B{C{url}} query, get and verify response. 

99 ''' 

100 if params: # build url query, don't map(quote, params)! 

101 p = _AMPERSAND_(*(Fmt.EQUAL(p, v) for p, v in params.items() if v)) 

102 if p: 

103 url = NN(url, _QUESTION_, p) 

104 u = urlopen(url, timeout=timeout) # secs 

105 

106 s = u.getcode() 

107 if s != 200: # http.HTTPStatus.OK or http.client.OK 

108 raise HTTPError('code %d: %s' % (s, u.geturl())) 

109 

110 r = u.read() 

111 u.close() 

112 # urlcleanup() 

113 return ub2str(r).strip() 

114 

115 

116def _xml(tag, xml): 

117 '''(INTERNAL) Get a <tag>value</tag> from XML. 

118 ''' 

119 # b'<?xml version="1.0" encoding="utf-8" ?> 

120 # <USGS_Elevation_Point_Query_Service> 

121 # <Elevation_Query x="-121.914200" y="37.881600"> 

122 # <Data_Source>3DEP 1/3 arc-second</Data_Source> 

123 # <Elevation>3851.03</Elevation> 

124 # <Units>Feet</Units> 

125 # </Elevation_Query> 

126 # </USGS_Elevation_Point_Query_Service>' 

127 i = xml.find(Fmt.TAG(tag)) 

128 if i > 0: 

129 i += len(tag) + 2 

130 j = xml.find(Fmt.TAGEND(tag), i) 

131 if j > i: 

132 return Str(xml[i:j].strip(), name=tag) 

133 return _no_(_XML_, Fmt.TAG(tag)) # PYCHOK no cover 

134 

135 

136class Elevation2Tuple(_NamedTuple): # .elevations.py 

137 '''2-Tuple C{(elevation, data_source)} in C{meter} and C{str}. 

138 ''' 

139 _Names_ = (_elevation_, 'data_source') 

140 _Units_ = ( Meter, Str) 

141 

142 

143def elevation2(lat, lon, timeout=2.0): 

144 '''Get the geoid elevation at an C{NAD83} to C{NAVD88} location. 

145 

146 @arg lat: Latitude (C{degrees}). 

147 @arg lon: Longitude (C{degrees}). 

148 @kwarg timeout: Optional, query timeout (seconds). 

149 

150 @return: An L{Elevation2Tuple}C{(elevation, data_source)} 

151 or (C{None, "error"}) in case of errors. 

152 

153 @raise ValueError: Invalid B{C{timeout}}. 

154 

155 @note: The returned C{elevation is None} if B{C{lat}} or B{C{lon}} is 

156 invalid or outside the C{Conterminous US (CONUS)}, if conversion 

157 failed or if the query timed out. The C{"error"} is the C{HTTP-, 

158 IO-, SSL-} or other C{-Error} as a string (C{str}). 

159 

160 @see: U{USGS Elevation Point Query Service<https://apps.NationalMap.gov/epqs/>}, the 

161 U{FAQ<https://www.USGS.gov/faqs/what-are-projection-horizontal-and-vertical- 

162 datum-units-and-resolution-3dep-standard-dems>}, U{geoid.py<https://Gist.GitHub.com/ 

163 pyRobShrk>}, module L{geoids}, classes L{GeoidG2012B}, L{GeoidKarney} and 

164 L{GeoidPGM}. 

165 ''' 

166 try: # alt 'https://NED.USGS.gov/epqs/pqs.php', 'https://epqs.NationalMap.gov/v1' 

167 x = _qURL('https://NationalMap.USGS.gov/epqs/pqs.php', 

168 x=Lon(lon).toStr(prec=6), 

169 y=Lat(lat).toStr(prec=6), 

170 units='Meters', # 'Feet', capitalized 

171 output=_XML_.lower(), # _JSON_, lowercase only 

172 timeout=Scalar(timeout=timeout)) 

173 if x[:6] == '<?xml ': 

174 e = _xml('Elevation', x) 

175 try: 

176 e = float(e) 

177 if fabs(e) < 1e6: 

178 return Elevation2Tuple(e, _xml('Data_Source', x)) 

179 e = 'non-CONUS %.2F' % (e,) 

180 except (TypeError, ValueError): 

181 pass 

182 else: # PYCHOK no cover 

183 e = _no_(_XML_, Fmt.QUOTE2(clips(x, limit=128, white=_SPACE_))) 

184 except Exception as x: # (HTTPError, IOError, TypeError, ValueError) 

185 e = repr(x) 

186 e = _error(elevation2, lat, lon, e) 

187 return Elevation2Tuple(None, e) 

188 

189 

190class GeoidHeight2Tuple(_NamedTuple): # .elevations.py 

191 '''2-Tuple C{(height, model_name)}, geoid C{height} in C{meter} 

192 and C{model_name} as C{str}. 

193 ''' 

194 _Names_ = (_height_, 'model_name') 

195 _Units_ = ( Meter, Str) 

196 

197 

198def geoidHeight2(lat, lon, model=0, timeout=2.0): 

199 '''Get the C{NAVD88} geoid height at an C{NAD83} location. 

200 

201 @arg lat: Latitude (C{degrees}). 

202 @arg lon: Longitude (C{degrees}). 

203 @kwarg model: Optional, geoid model ID (C{int}). 

204 @kwarg timeout: Optional, query timeout (seconds). 

205 

206 @return: An L{GeoidHeight2Tuple}C{(height, model_name)} 

207 or C{(None, "error"}) in case of errors. 

208 

209 @raise ValueError: Invalid B{C{timeout}}. 

210 

211 @note: The returned C{height is None} if B{C{lat}} or B{C{lon}} is 

212 invalid or outside the C{Conterminous US (CONUS)}, if the 

213 B{C{model}} was invalid, if conversion failed or if the query 

214 timed out. The C{"error"} is the C{HTTP-, IO-, SSL-, URL-} 

215 or other C{-Error} as a string (C{str}). 

216 

217 @see: U{NOAA National Geodetic Survey 

218 <https://www.NGS.NOAA.gov/INFO/geodesy.shtml>}, 

219 U{Geoid<https://www.NGS.NOAA.gov/web_services/geoid.shtml>}, 

220 U{USGS10mElev.py<https://Gist.GitHub.com/pyRobShrk>}, module 

221 L{geoids}, classes L{GeoidG2012B}, L{GeoidKarney} and 

222 L{GeoidPGM}. 

223 ''' 

224 try: 

225 j = _qURL('https://Geodesy.NOAA.gov/api/geoid/ght', 

226 lat=Lat(lat).toStr(prec=6), 

227 lon=Lon(lon).toStr(prec=6), 

228 model=(model if model else NN), 

229 timeout=Scalar(timeout=timeout)) # PYCHOK indent 

230 if j[:1] == _LCURLY_ and j[-1:] == _RCURLY_ and j.find('"error":') > 0: 

231 d, e = _json(j), 'geoidHeight' 

232 if isinstance(_xkwds_get(d, error=_n_a_), float): 

233 h = d.get(e, None) 

234 if h is not None: 

235 m = _xkwds_get(d, geoidModel=_n_a_) 

236 return GeoidHeight2Tuple(h, m) 

237 else: 

238 e = _JSON_ 

239 e = _no_(e, Fmt.QUOTE2(clips(j, limit=256, white=_SPACE_))) 

240 except Exception as x: # (HTTPError, IOError, ParseError, TypeError, ValueError) 

241 e = repr(x) 

242 e = _error(geoidHeight2, lat, lon, e) 

243 return GeoidHeight2Tuple(None, e) 

244 

245 

246if __name__ == '__main__': 

247 

248 from pygeodesy import printf 

249 # <https://WikiPedia.org/wiki/Mount_Diablo> 

250 for f in (elevation2, # (1173.79, '3DEP 1/3 arc-second') 

251 geoidHeight2): # (-31.699, u'GEOID12B') 

252 t = f(37.8816, -121.9142) 

253 printf(_COLONSPACE_(f.__name__, t)) 

254 

255# **) MIT License 

256# 

257# Copyright (C) 2016-2025 -- mrJean1 at Gmail -- All Rights Reserved. 

258# 

259# Permission is hereby granted, free of charge, to any person obtaining a 

260# copy of this software and associated documentation files (the "Software"), 

261# to deal in the Software without restriction, including without limitation 

262# the rights to use, copy, modify, merge, publish, distribute, sublicense, 

263# and/or sell copies of the Software, and to permit persons to whom the 

264# Software is furnished to do so, subject to the following conditions: 

265# 

266# The above copyright notice and this permission notice shall be included 

267# in all copies or substantial portions of the Software. 

268# 

269# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 

270# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 

271# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 

272# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 

273# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 

274# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 

275# OTHER DEALINGS IN THE SOFTWARE. 

276 

277# % python -m pygeodesy.elevations 

278# elevation2: (1173.79, '3DEP 1/3 arc-second') 

279# geoidHeight2: (-31.703, 'GEOID12B')