ArcGIS Survey Analyst extension supports .gsi import
Survey Analyst imports and exports measurements and other field data from Total Positioning System (TPS) equipment using the following survey data converter formats: ASCII converter, Geodimeter converter, GSI converter, SDR converter, TDS coordinate converter, and TDS raw converter.
The data import utility can be extended programmatically to import additional data formats.
Which data formats can be imported into a survey project?
You can also convert points to polygons (min of 3 points) programmatically for automating land parcel creation.