[Qgis-user] Circular Lines in QGIS

[Adam Dershowitz]

No, they aren’t great circle.  For example, look at the route from Boston to Denver, and then from New York to Denver.  One goes far south (over Atlanta), and the other goes way north (over Canada), but both great circle routes should be fairly close to each other.  They start at cities that are perhaps 200 miles apart, and the middle of the routes are 700 miles apart, to get to the same location.  

--Adam



> On Sep 26, 2018, at 5:54 PM, Wolstan H M Dixie <wolstan-dixie at hotmail.co.uk> wrote:
> 
> I don't know but am guessing, but aren't those lines not just *any* circular arcs, but the actual great-circle paths (the shortest line between two points on the surface of a globe) plotted onto that map projection? Some of them towards the edges aren't circular.
> 
> On 26/09/2018 21:34, C Hamilton wrote:
>> I had a user request Circular Lines in the Shape Tools plugin and they gave the following example.
>> 
>> https://www.stayaspensnowmass.com/sites/default/files/aspenFlightMap.jpg <https://www.stayaspensnowmass.com/sites/default/files/aspenFlightMap.jpg>
>> 
>> I don't know how one would do this type of drawing. Does anyone have any ideas? It draws the lines trying to avoid overlapping other lines in a very pleasing manner. Doing this is probably outside the scope of the Shape Tools plugin, but I just wanted to ask to see if there is a relatively easy algorithmic way of drawing these types of lines between two points.
>> 
>> Thanks,
>> 
>> Calvin
>> 
>> 
>> 
>> _______________________________________________
>> Qgis-user mailing list
>> Qgis-user at lists.osgeo.org <mailto:Qgis-user at lists.osgeo.org>
>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user <https://lists.osgeo.org/mailman/listinfo/qgis-user>
>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user <https://lists.osgeo.org/mailman/listinfo/qgis-user>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20180926/8d5a9306/attachment.html>