OD Matrix miscalculates time cost if network CRS does not use linear units of meters #36
Description
QNEAT3 does not correctly apply a unit conversion if the network layer uses a CRS with linear units other than meters for time-optimization. For example, one speed cost was calculated as 36 seconds in a network layer using meters, but once projected to a coordinate system using feet, the cost was calculated at 118 seconds -- incorrect by the same factor as the conversion from feet to meters.
It seems like the QGIS network builder is automatically converting linear units into meters using self.meter_to_unit_factor , so calling the speed strategy function with a speed conversion factor of unit_to_meter_factor * 1000.0 / 3600.0 is negating the unit conversion that has already been applied to distance. I'm making an educated guess here, since I can't find the code in the QGIS algorithms where the linear unit conversion happens, but clearly it happening for distance strategy and I assume that it must also be doing the same for speed strategy. In either cases, revising unit_to_meter_factor * 1000.0 / 3600.0 to 1000.0 / 3600.0 is fixing the bug.