https://svn.boost.org/trac10/ticket/10959 <p> In cartesian relate strategy for collinear segments overlapping very tiny parts of each other the segments are detected as collinear(using ratios) but only one intersection point is generated. This is an unexpected state in get_turn_info collinear handler. </p> <pre class="wiki">"POLYGON((-0.59322033898305082 -8.0508474576271194,-2.882352941176471 -7.7647058823529411,-2.8823529411764706 -7.7647058823529411,-3.7361111111111112 -6.5694444444444446,-3.4404145077720205 -5.766839378238342,-4.1864406779661012 -3.6779661016949152,-7.5252525252525251 -5.5858585858585865,-7.5862068965517242 -5.1896551724137936,-4.47887323943662 -2.859154929577465,-4.5789473684210531 -2.5789473684210527,-3 -1,-2.9310344827586206 -0.86206896551724144,-3.1764705882352944 -0.70588235294117663,-4.7401960784313726 -2.1274509803921577,-5.3255813953488369 -0.48837209302325502,-4.7872340425531918 0.31914893617021284,-5.8571428571428577 1.0000000000000007,-5.3255813953488369 -0.48837209302325502,-5.9473684210526319 -1.4210526315789465,-8 2,-7.7333333333333334 2.1939393939393939,-8.8294573643410867 2.891472868217055,-8.8556701030927822 3.061855670103093,-7.5999999999999996 3.6000000000000001,-7.7999999999999998 3.7999999999999998,-7.75 3.7916666666666665,-7.5471698113207548 3.6226415094339623,-7.3200000000000003 3.7200000000000002,-3.473684210526315 3.0789473684210527,-3.2549019607843133 3.2156862745098036,-2.9999999999999982 3.1428571428571423,-3.1733333333333325 3.2666666666666666,-2.9180327868852456 3.4262295081967209,-2.8723404255319145 3.1063829787234041,-2.1111111111111112 2.8888888888888888,-2.1428571428571428 2.8571428571428572,-1.8433734939759043 2.8072289156626509,-1.8396226415094346 2.8113207547169816,-1.6486486486486487 2.756756756756757,-1.76510067114094 2.8926174496644301,-0.53846153846153855 4.2307692307692308,1.8148148148148147 5.4074074074074074,1.588235294117647 2.2352941176470589,1.819672131147541 2.1967213114754101,2 4,2 2.1666666666666665,2.3538461538461544 2.1076923076923078,2 1.6875000000000004,2 -2,1.2173913043478262 -3.8260869565217392,1.7375886524822697 1.3758865248226959,1.5073170731707317 1.1024390243902444,1.1428571428571428 -4,-0.59322033898305082 -8.0508474576271194),(1.666666666666667 1.5999999999999988,1.5675675675675675 1.8378378378378377,1.4374999999999991 1.8750000000000002,1.0487804878048776 2.3414634146341466,0.46666666666666712 2.6060606060606055,0.086956521739131043 2.2608695652173911,1.4374999999999991 1.8750000000000002,1.666666666666667 1.5999999999999988))" "POLYGON((-2.333333333333333 -8.6666666666666661,-4.3253012048192767 -8.168674698795181,-4.1194968553459113 -7.6100628930817606,-2.8823529411764706 -7.7647058823529411,-2.882352941176471 -7.7647058823529411,-2.263157894736842 -8.6315789473684212,-2.333333333333333 -8.6666666666666661))" </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/10959 Trac 1.4.3 awulkiew Fri, 23 Jan 2015 16:23:01 GMT https://svn.boost.org/trac10/ticket/10959#comment:1 https://svn.boost.org/trac10/ticket/10959#comment:1 <ul> <li><strong>status</strong> <span class="trac-field-old">new</span> → <span class="trac-field-new">closed</span> </li> <li><strong>resolution</strong> → <span class="trac-field-new">fixed</span> </li> <li><strong>milestone</strong> <span class="trac-field-old">To Be Determined</span> → <span class="trac-field-new">Boost 1.58.0</span> </li> </ul> <p> Fix: <a class="ext-link" href="https://github.com/boostorg/geometry/commit/38389101829ed993523730ecedcd097fbf1ec70b"><span class="icon">​</span>https://github.com/boostorg/geometry/commit/38389101829ed993523730ecedcd097fbf1ec70b</a> </p> Ticket