is_simple? Does Not Return False

[workmaster2n]

A simple polygon does not intersect itself.

points2= [[0,0],[1,1],[1,0],[2,1]]

ring2 = factory.linear_ring( points2.map { |point| factory.point(point[0], point[1])})
polygon2 = factory.polygon(ring2)

polygon2.is_simple? # should be FALSE, returns TRUE

This appears to cause another issue with intersection (from Google Groups: https://groups.google.com/forum/#!topic/rgeo-users/lZNn9T0mbUc)

points = [[13.47252793455753, 290.4766485546728],
  [15.54073426239082, 276.35055725990753],
  [21.90820951900018, 303.537522515156],
  [8.213611305931236, 296.67601244677155],
  [15.856670355018885, 288.5390965152138],
  [5.203107005628723, 282.8149364819326],
  [11.645108176884317, 293.92931144857505],
  [21.47576740464814, 270.17134399422736],
  [29.567834075055067, 295.4682035260122],
  [48.068092286949536, 270.3459504624785],
  [43.03794739858885, 258.13815141284425],
  [55.64874297500046, 280.60030199869936],
  [32.032323591078075, 280.0517447031193],
  [49.87548537467882, 258.4676114262518],
  [59.63260599700384, 277.04500320083656],
  [31.614857616326788, 258.431620967041],
  [53.87189907349915, 265.80523647228813],
  [52.316443015244246, 261.3094217374252],
  [30.37850602489661, 243.96629767610517],
  [37.08920720717105, 252.6877424786614],
  [37.67156320109957, 256.0991612787459],
  [49.7584728112775, 268.3759102823432],
  [59.74319735148887, 264.2208658108574],
  [60.54396507940886, 245.38971341527755],
  [57.564649888497605, 250.08403853549206],
  [39.682138626675425, 259.0749883694973],
  [62.00527379837224, 263.58136799797455],
  [65.05145753546759, 272.02541066609746],
  [83.31572356144625, 254.90296245666315],
  [92.25465895580949, 263.29479945303524],
  [100.81651519586794, 244.4781415919933],
  [97.38250503130493, 243.78791706757247],
  [87.49444190296876, 243.9105261298119],
  [81.82798724390774, 269.6598019646186],
  [80.71955318698129, 260.49555506489577],
  [85.00768677074382, 276.00048670421893],
  [80.10443410251679, 268.8426712207494],
  [91.08764526469497, 271.26692548675146],
  [85.8450963377431, 248.78985255565703],
  [106.03331426082401, 285.6862023617447],
  [81.48185571652127, 276.64182698469585],
  [92.13991556203014, 271.2485875583364],
  [98.38365036214643, 281.45797323863655],
  [102.14553720914083, 278.80697248987985],
  [95.79149025730165, 279.82358453431533],
  [95.38236405117578, 278.8826046839788],
  [79.84595372109368, 285.0388151062105],
  [109.71787571959159, 283.02108741182485],
  [112.05321670679596, 301.5399519356833],
  [96.82862362239786, 272.33343670783256],
  [112.54061379482926, 284.36252505248075],
  [109.06903277165821, 297.19078942883584],
  [75.13325825094185, 308.9704604638807],
  [83.55187277360703, 295.0546419466594],
  [88.84790298938569, 292.9639477216925],
  [75.29244966532377, 295.0210099208458],
  [75.23335443874339, 282.4739464327858],
  [67.91530620904584, 323.50955164491853],
  [63.296053254751605, 298.995544235466],
  [71.80246436883493, 324.3318894704985],
  [64.48794851576415, 309.1294987323138],
  [69.62609875481044, 292.7394221824507],
  [48.95124034776636, 301.7575544233305],
  [84.55514650058575, 303.92593114667574],
  [43.235417508838566, 306.80206762714073],
  [34.73892220880614, 329.1907286303983],
  [52.281451303202594, 301.6084275695357],
  [28.5553253406923, 313.78687528227863],
  [42.59416401736963, 314.44364573586654],
  [33.96574556983046, 331.63047327518854],
  [37.38616713845671, 329.6824866871678],
  [23.131715778639652, 311.4013991985247],
  [15.828757564139648, 323.0965255455127],
  [21.96675393525481, 328.47311769889797],
  [2.9080724237548132, 328.7687465564651],
  [10.505827766014386, 318.71044965218437],
  [21.19898160178375, 333.79701722368725],
  [-1.2563038057836753, 308.56001944644083],
  [16.032524269458786, 313.86497375252344],
  [10.364272681542873, 289.536695054825],
  [12.05479520856448, 297.99725674515264],
  [21.14666849486861, 309.9853339832766],
  [1.3061680539270597, 322.6074468000856],
  [7.3768561576888025, 309.9450393773967],
  [-11.97992962187135, 308.21316177663465]]


ring = factory.linear_ring( points.map { |point| factory.point(point[0], point[1])})

polygon = factory.polygon(ring)
polygon.intersects?(polygon) 

polygon.intersection(polygon) # Should not be nil

I believe is_simple? relies on the GEOS library, so we might have to dig into the wrapper.

[jgandt]

I'm still seeing this issue. Any thoughts or movement on it? I have tried to debug, but to no avail thus far.

This renders CAPI unusable for my situation.

[teeparham]

is_simple? depends on the factory. I confirmed that is_simple? incorrectly returns true with RGeo::Geos::CAPIFactory for the above test case.

[ronanduddy]

Hi the FFI and Geographic mercator factories appear to also return true when they are meant to return false:

::RGeo::Geos::FFIFactory.new.parse_wkt('POLYGON ((-73.0 40.0, -73.5 40.0, -73.0 40.5, -73.5 40.5, -73.0 40.0))').is_simple?

::RGeo::Geographic.simple_mercator_factory.parse_wkt('POLYGON ((-73.0 40.0, -73.5 40.0, -73.0 40.5, -73.5 40.5, -73.0 40.0))').is_simple?

Image below of the example polygon.