STAR*DNA Log File states: Backsight and Foresight station names are the same

This error can appear when attempting to convert a gsi file using a Leica DNA convertor.

There are two possible causes of this issue:

1. The level loop consists of a single backsight and foresight to the same station, and intermediate shots and/or instrument moves through turnpoints.  The STAR*DNA conversion utility assumes that you will have at least one intermediate station in your level data so will alert you if you do not have have one.  

If you need to complete a level loop as described above you can resolve the issue in the field by ensuring that you use an alias name for the last foresight to your closing point and adding a .alias name inline entry in your final dat file to tell STAR*NET to treat the original and alias point as the same point.

If you have already completed the fieldwork you can resolve this issue by manually editing the GSI file to change the station name to an alias name.  See the entry below for an example of how to change Station A to Station A1:

before:

11....+0000000A 32...6+00124319 332.06+00031288 

after:

11....+000000A1 32...6+00124319 332.06+00031288 

2. This error message can also be triggered if the IDs used during fieldwork have not made clear to STAR*NET which points to treat as stations and which points to treat as turnpoints.  This is usually resolved once the office and field crews meet and determine how best to assign Station IDs so that the converter dialog can be configured in the area indicated below:

This requirement is described in more detail in Appendix C|STAR*NET Conversion Utilities in the STAR*NET Help files.  Look for "Naming the Level Line Benchmark or Junction Stations"

If your data has already been collected, this article explains a procedure that will allow you to edit your data and still work with it.  But it's still better to modify the field procedures for future projects.