BaseCamp for Mac Version 4.2.4 (4.2.4) running on a 20 inch mid 2007 iMac with 4GB memory running OS/X 10.9.1
Workflow Goal: I have a list of waypoints from a third party in Lat/Lon hddd.ddddd form, however the actual waypoints only have 4 digit precision. My task is to put them into BaseCamp and then check their position on the Garmin maps, in this case I am using City Navigator North America NT 2014.3 which is a download pursuant to a Lifetime map subscription associated with my BMW branded Nav-V device. If the waypoint is not located on the required map feature, usually a road bed, then I am to reposition it onto the feature, note the new coordinates and eventually send the corrected list along with a GPX file back to the 3rd party in the same 4 digit precision that I started with.
Workflow steps:
1. CMD+L to open the Locate Coordinates: window
2. Typically the coordinates from the last waypoint I created have already populated the Locate Coordinates window
3. Reposition the cursor using the Arrow keys and then use the Backspace key to remove un-needed digits from the mantissa and replace them with the required four digits from my list.
4. Right Click Create Waypoint At... and the Get Info window opens showing the General tab
5. Click on Show on Map and the map pane moves to the newly created waypoint.
6. Zoom in to 80 ft scale (overzoom)
6. Use Option key and Mouse to drag waypoint to map feature.
7. Click on Advanced tab to reveal Position field
8. If the last digit of both Lat and Lon is not zero then use rounding rules to round mantissa's down to four digits and correct the mantissa by changing the minimum number of digits and then hitting enter. If the least significant digit differs by 2 or less from the desired value then I get the this ERROR: In all instances the mantissas change back to the original numbers. Here is an example point: Nxx.42388 Wxxx.23170. I want to change xx.42388 to xx.4239. I delete the 88 and enter either 9 or 90 hit Enter and I get xx.42388 back. I can usually correct it by moving the new Waypoint again far away using the Option key and the Mouse and then typing in the desired new mantissa. Just typing in the new mantissa or even just the full coordinates alone does not work.
By way of experiment I have tried changing the Lon mantissa by one least significant digit, then two and then three, e.g. from the original 42397, to 42396, then to 42395 and then to 42394 and the change finally sticks by the 3rd digit change. Seems to work for Lat, too. So, the simple workaround for my use case is: if the mantissa differs by two or less then add ten to the required change and add the total to the mantissa and hit enter then subtract ten from the resulting mantissa and hit enter again to reposition the waypoint to the desired location.
