Information for any n4ce users taking delivery of Leica’s new AP20 tilt pole!
We have just updated the n4ce BETA download in the Client Area of our website to the 8th June 2022.
You now have the option on import to keep or discard the tilt corrections.
If you discard, the observations will be as if the pole is held vertically above the point. The reason we have added this is that it has come to light that if a user changes from local to OS control in n4ce (by changing the coordinates of their stations) using versions May 27th onwards, it could alter the orientation of the setups, relative to the tilt corrections.
We now trap this and pass on the additional orientation necessary to bring the tilt correction back in sync with the new coordinate system.
So using the 8th June version it does not matter if the observations are tilt corrected or not, in that situation.
In testing, we have found between 2-5mm difference in the position of detail points between changing the control over to OS station coordinates and doing a reduction, versus reducing in local grid and then transforming to OS after. This is to be expected when you take into account that the OS stations will not be exactly the same distance apart or have exactly the same position relative to each other, compared to their original locally derived positions.
If you are in doubt just select the No option when importing and everything will proceed as normal. Though changing the prism constant or target height of AP20 points would not have the effect it should, because the Tilt information is no longer present.
Be aware also, that if for whatever reason the backsight station is changed in n4ce for a setup, then that will likely not correctly pass on the AP20 tilt because the backsight station may not be known yet if the control is still to be adjusted. In that situation, you would need to select the option to discard tilt data on import so that the survey can be processed as normal without any tilt corrections.
Should you have any further queries regarding this update, please email Tech Support at support@appsincadd.co.uk
