New answers tagged c++
Use CPLSetConfigOption. See the Config Options docs.
Foreword : I think you mean «proprietary» and not «commercial». Any opensource product can be a commercial product, even GPL ones. You can write plugins for QGIS in C++ or Python, the latter being advised, as it simplifies plugins distribution and deployment. QGIS is licenced as GPL, and the Python bindings are GPL too. So is PyQT, which is used in QGIS ...
I'm not sure that it works fine in C#, however, Point is 1 dimension geometry which doesn't contain valid extent. So, I recommended to use Point geometry instead of using Envelope geometry. Here is the sample code, and also I fixed some part of code which was verbose. //Create Point IPointPtr ipPoint(CLSID_Point); ipPoint->PutCoords( dX, xY); //Open ...
You might try looking at OpenCV library. It is better suited for such tasks. http://docs.opencv.org/doc/tutorials/imgproc/imgtrans/hough_circle/hough_circle.html
As the question has evolved, sorry for the answer not really matching the title. When building a custom application using the QGIS libraries, or running stock QGIS, you have to tell the QGIS core, where it will find these libraries (especially the providers). The PyQGIS cookbook contains information which also applies to C++ applications. This can either ...
Top 50 recent answers are included