Changes to the FIXZ command to allow locking Z for sensors with ellipsoidal Z

The ADS 40/80, VM Quasi-Panoramic (A3 camera) and satellite sensors work in the reference coordinate system WGS 84 3D (EPSG code:4979). The coordinate Z for these sensors is always ellipsoidal, so if we do not use an absolute orientation that has assigned a reference coordinate system with a vertical orthometric system, by blocking the coordinate Z we will be blocking it in the ellipsoidal system. When the operator locks the coordinate Z, he usually wants it to be locked in an orthometric Z coordinate. As these particular sensors work with ellipsoidal Z coordinate, coordinate Z actually has to be moved, since it must be transformed from that orthometric Z coordinate locked by the user into its corresponding ellipsoidal Z coordinate, so the expected behavior when locking coordinate Z when loading a model of the sensors indicated above is that it moves according to the geoid model selected for transformation. How can we make the coordinate Z of these sensors orthometric and not ellipsoidal? One option is to perform an absolute orientation whose ground control points are in a virtual orthometric coordinate system, such as: ETRS89 / UTM Zone 30N + REDNAP Peninsula. If we do not have ground control points the thing is not so simple, because we do not have points to measure. We have made a modification to the command of FIJA_Z. Until now this command blocked the coordinate Z in the coordinate that had the photogrammetric window when activated. Now it is not so, now it will be blocked in the coordinate Z that has the drawing window. If the drawing window has associated a vertical orthometric coordinate system (say for example that the drawing window is in the system ETRS89 / UTM Zone 30N + REDNAP Peninsula), when activating the lock of Z, Digi3D.NET will perform the following algorithm:

1. The photogrammetric window receives a movement from the user. Let's say Latitude,Longitude,h
2. As the lock of Z is enabled, that coordinate is transformed to the coordinate system of the drawing window, resulting in X,Y,Z.
3. The coordinate Z is replaced by the coordinate of the Z blocked resulting in X,Y,Zblock.
4. It retransforms to the coordinate system of the photogrammetric window, resulting in Latitude,Longitude,Zelipsoidal for the lock Z.
5. Images of those coordinates are displayed in the photogrammetric window.

In this way the vertical coordinate system in which the photogrammetric window is locked is defined by the drawing window and not by the photogrammetric window. If in the drawing window we are working in geographic coordinates 3D (with Z ellipsoidal) means that we want to make contour lines with ellipsoidal Z coordinates, therefore the final transformed point will not change the Z coordinate. If on the contrary in the drawing window we indicate an orthometric vertical coordinate system, the locking will be done in orthometric coordinates. [youtube:http://youtu.be/1wEuFCUCKDs]