Hi, To my knowledge no. The second option would be a polygone that covers the earth but that has a hole in it. That is the Generally accepted topology in GIS.
Nicolas Cadieux Ça va bien aller! > Le 16 juin 2020 à 10:28, Tudorache, Marian <marian.tudora...@navcanada.ca> a > écrit : > > Hi everyone, > > I have a list of polygons given by a list of points. > The polygons are properly drawn on QGIS canvas by creating the geometries, > the each geometry is used to create a Qgsfeature which are saved on a > shapefile. > The problem appears in detecting if a point on the Earth is inside or outside > the polygon. > Using pyqgis QgsGeometry intersects function returns proper value. > However when I export the polygon to intermaphics from Kongsberg Geospatial > (former Gallium) sometime the point is inside other time is outside the > polygon. > I tried to switch the order of the points is QGIS ,but the intersects > function always give me the same result regardless of the order of the points. > In intermaphics the intersection between a polygon and a point varies with > the order of the points which define a polygon. > I talked to people from gallium and they confirmed the order of the points is > important. > In one direction a inner area of the polygon is the small surface and if I > switch the order the inner area is the outside and it wraps the Earth on the > opposite side. > > Does QGIS or pyqgis has a similar mechanism to determine which is the inner > part of the polygon on a sphere or ellipsoid? > > Thanks, > Marian > > ________________________________ > > This electronic message, as well as any transmitted files included in the > electronic message, may contain privileged or confidential information and is > intended solely for the use of the individual(s) or entity to which it is > addressed. If you have received this electronic message in error please > notify the sender immediately and delete the electronic message. Any > unauthorized copying, disclosure or distribution of the electronic message is > strictly forbidden. NAV CANADA accepts no liability for any damage caused by > any virus and/or other malicious code transmitted by this electronic > communication. > > Le présent message électronique et tout fichier qui peut y être joint peuvent > contenir des renseignements privilégiés ou confidentiels destinés à l’usage > exclusif des personnes ou des organismes à qui ils s’adressent. Si vous avez > reçu ce message électronique par erreur, veuillez en informer l’expéditeur > immédiatement et supprimez le. Toute reproduction, divulgation ou > distribution du prése _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
