Hi Calvin On Mon, Apr 3, 2017 at 11:00 PM, C Hamilton <[email protected]> wrote: > I had been wondering what algorithm is being used for the methods azimuth, > distance, and project in the QgsPoint class, but in looking at the code it > is simply cartesian plane math. It looks like the qgsdistancearea class is > using vincinty math if I am examining the code correctly. > > Vincinty is more accurate than the great circle, but fails in some cases and > there are more accurate methods. I apologize if I have failed to find the > right classes and methods in the API, but why doesn't the API provide the > more accurate geodesic calculations that are in geographiclib. It also seems > like it would be good to also provide great circle math as an option. Am I > missing it in the API or is it simply not there? If it is not there is > anyone working on adding it?
QgsDistanceArea is currently the only class in QGIS for doing measurements - either euclidean or using Vincenty's formulae. I have not heard about anyone currently working on adding more methods for calculation of distances or areas. I am no expert in geodesic calculations - what other methods would you like to have in QGIS and how are their results different from Vincenty's formulae? > Are there any efforts going on to flesh out the QGIS API a little more. > Generally, the methods and parameters are not well documented if it is not > obvious from the name. Nowadays there is quite a lot of effort being done to improve QGIS API for the upcoming release of 3.0. Please feel free to join the effort and submit pull requests on this topic - that would be very appreciated! Cheers Martin _______________________________________________ Qgis-developer mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
