Module: AdiwgCoordinates

Defined in:
lib/adiwg/mdtranslator/internal/module_coordinates.rb

Overview

History:

Stan Smith 2017-08-23 added is_polygon_clockwise method
Stan Smith 2017-05-24 added checkGeometry method to move objects to real world
Stan Smith 2016-11-10 added computedBbox computation
Stan Smith 2015-07-16 moved module_coordinates from mdJson reader to internal
Stan Smith 2015-07-14 refactored to remove global namespace constants
Stan Smith 2015-06-22 replace global ($response) with passed in object (responseObj)
Stan Smith 2014-12-15 refactored to handle namespacing readers and writers
Stan Smith 2014-05-23 added getLevels

Stan Smith 2013-11-13 added getDimension Stan Smith 2013-11-07 original script

Class Method Summary collapse

Class Method Details

.addPoint(aPoint, aNorthings, aEastings) ⇒ Object

add to tuple to an array



221
222
223
224
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 221

def self.addPoint(aPoint, aNorthings, aEastings)
   aEastings << aPoint[0]
   aNorthings << aPoint[1]
end

.checkGeometry(aCoords, aNorthings, aEastings) ⇒ Object

move geometry to real world if possible move geometry to a single spanned meridian



169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 169

def self.checkGeometry(aCoords, aNorthings, aEastings)

   aGeoNorthings = []
   aGeoEastings = []

   unpackCoords(aCoords, aGeoNorthings, aGeoEastings)

   minEast = aGeoEastings.min
   maxEast = aGeoEastings.max

   # if all coordinates in -1 or +1 world, move back to real world
   if maxEast < -180
      aGeoEastings.collect! { |x| x + 360 }
   end
   if minEast > 180
      aGeoEastings.collect! { |x| x - 360 }
   end

   minEast = aGeoEastings.min
   maxEast = aGeoEastings.max

   # if geoObject spans a meridian, find out which one and make it default
   if @spanWorld == 0
      @spanWorld = -1 if maxEast < 0 && minEast < -180
      @spanWorld = 1 if minEast > 0 && maxEast > 180
   end

   # bring -1 and +1 world objects back into default meridian world
   if @spanWorld == -1 && maxEast > 180
      aGeoEastings.collect! { |x| x - 360 }
   end
   if @spanWorld == 1 && minEast < -180
      aGeoEastings.collect! { |x| x + 360 }
   end

   aEastings.concat(aGeoEastings)
   aNorthings.concat(aGeoNorthings)

end

.computeBbox(aGeo) ⇒ Object

compute bounding box



67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 67

def self.computeBbox(aGeo)

   # reset spanned world to 0 before computing bounding box
   @spanWorld = 0

   # find all the eastings (x) and northings (y) in the GeoJSON object
   aNorthings = []
   aEastings = []
   aGeo.each do |hGeo|
      unpackGeometry(hGeo, aNorthings, aEastings)
   end

   # return if no coordinates found in geographic object(s)
   return {} if aNorthings.empty? || aEastings.empty?

   # find most north/south points
   north = aNorthings.max
   south = aNorthings.min

   # find most east/west spanning the meridian
   eastM = aEastings.max
   westM = aEastings.min

   # find most east/west spanning the anti-meridian
   aPositiveEast = []
   aNegativeEast = []
   aEastings.each do |east|
      aNegativeEast << east if east < 0.0
      aPositiveEast << east if east >= 0.0
   end
   aNegativeEast.uniq!
   aPositiveEast.uniq!

   eastAM = aNegativeEast.max
   westAM = aPositiveEast.min

   # if eastings are all positive or all negative hemisphere is decided
   if aPositiveEast.empty? || aNegativeEast.empty?
      east = eastM
      west = westM
   else
      # choose which meridian to span based on smaller edge-to-edge distance
      distanceM = eastM - westM
      distanceAM = (180 + eastAM) + (180 - westAM)
      if distanceM.abs <= distanceAM.abs
         # this spanned to  meridian
         east = eastM
         west = westM
      else
         # this spanned tne anti-meridian
         east = eastAM
         west = westAM
      end
   end

   bBox = {}
   bBox[:westLongitude] = west
   bBox[:eastLongitude] = east
   bBox[:southLatitude] = south
   bBox[:northLatitude] = north

   return bBox

end

.getDimension(aCoords) ⇒ Object

get the number of dimensions in a coordinate array



43
44
45
46
47
48
49
50
51
52
53
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 43

def self.getDimension(aCoords)

   if aCoords[0].kind_of?(Array)
      coordDim = getDimension(aCoords[0])
   else
      coordDim = aCoords.length
   end

   return coordDim

end

.getLevels(aCoords) ⇒ Object

get the number of levels in the coordinate array



56
57
58
59
60
61
62
63
64
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 56

def self.getLevels(aCoords)

   i = 1
   if aCoords[0].kind_of?(Array)
      i = i + getLevels(aCoords[0])
   end
   return i

end

.is_polygon_clockwise(aCoords) ⇒ Object 



226
227
228
229
230
231
232
233
234
235
236
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 226

def self.is_polygon_clockwise(aCoords)
   area = 0.0
   i = 0
   n = aCoords.length - 1
   until i == n
      area += (aCoords[i][0] * aCoords[i+1][1]) - (aCoords[i][1] * aCoords[i+1][0])
      i += 1
   end
   area += (aCoords[n][0] * aCoords[0][1]) - (aCoords[n][1] * aCoords[0][0])
   return area >= 0 ? false : true
end

.stringifyCoords(aCoords, responseObj) ⇒ Object

repack coordinate array into single string for ISO



20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 20

def self.stringifyCoords(aCoords, responseObj)

   s = ''
   i = 0
   coordCount = aCoords.length
   aCoords.each do |coord|
      if coord.kind_of?(Array)
         s = s + unpack(coord, responseObj)
      else
         i += 1
         s = s + coord.to_s
         if i < coordCount
            s = s + ','
         end
         s = s + ' '
      end
   end

   return s

end

.unpackCoords(aCoords, aNorthings, aEastings) ⇒ Object

unpack coordinate arrays



210
211
212
213
214
215
216
217
218
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 210

def self.unpackCoords(aCoords, aNorthings, aEastings)
   if aCoords[0].kind_of?(Array)
      aCoords.each do |aTuple|
         unpackCoords(aTuple, aNorthings, aEastings)
      end
   else
      addPoint(aCoords, aNorthings, aEastings)
   end
end

.unpackGeometry(hGeo, aNorthings, aEastings) ⇒ Object

compute bounding box



133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
 
# File 'lib/adiwg/mdtranslator/internal/module_coordinates.rb', line 133

def self.unpackGeometry(hGeo, aNorthings, aEastings)

   # geometry objects
   type = hGeo[:type]
   if %w{ Point LineString Polygon MultiPoint MultiLineString MultiPolygon }.one? {|word| word == type}
      checkGeometry(hGeo[:coordinates], aNorthings, aEastings)
   end

   # geometry collections
   if hGeo[:type] == 'GeometryCollection'
      hGeo[:geometryObjects].each do |aGeoObj|
         checkGeometry(aGeoObj[:coordinates], aNorthings, aEastings)
      end
   end

   # features
   if hGeo[:type] == 'Feature'
      featureType = hGeo[:geometryObject][:type]
      if featureType == 'GeometryCollection'
         unpackGeometry(hGeo[:geometryObject], aNorthings, aEastings)
      else
         checkGeometry(hGeo[:geometryObject][:coordinates], aNorthings, aEastings)
      end
   end

   # feature collections
   if hGeo[:type] == 'FeatureCollection'
      hGeo[:features].each do |hFeature|
         unpackGeometry(hFeature, aNorthings, aEastings)
      end
   end

end