Skip to content

---- 3.1.1 Import Existing Topography

Last Updated: 29 June 2022         For: OptiSurface Designer V3+

Overview: Import (Survey File) Existing Topography to generate a working surface to calculate analysis and designs on.

Displayed By: File > Import Existing Topography
Click Import toolbar

Here are the survey file formats supported.

Trimble Field Level Survey File (.txt)

Format: point number, easting, northing, elevation, code
First line with Master Benchmark with code 'MB', latitude, longitude
Other Benchmarks with code 'BM1', 'BM2', etc
Boundary polygon with code 'B'
Coordinate System: Local XY (True North) with Elevation on WGS84 Datum

Generic Survey File (.xyz)

Format: as per Trimble WM Survey File above but no point number required in first column.

Ag Survey File (.ags)

Description: Import of freeform elevations and other collected points. Will require processing within OS before design functions can begin.
Format: 4 column CSV. Can have header line. Latitude (deg), Longitude (deg), Elevation Existing(m), Code
Elevation is always be assumed to be meters. It should be the Altitude given in the standard NMEA GGA string as by default this is corrected to the 10x10degree geod built into every GPS.

0mb_4g --> First point in file is always assumed to be the master benchmark. It can be called anything but reference point for the rest of the points.
0cp01 --> Special points (eg benchmarks or points of interest) start with a leading 0 significant
2PER --> Perimeter. All polylines or polygons including perimeter start with a '2'.
3GRD --> Elevation point. All random points start with a '3'.
21E --> All polylines or polgons start with a '2'. some sort of named elevation path. like a bank, or ditch.

It possible to supply a file that only has 3GRD points but first point will still be assumed to be the Master Benchmark.

Coordinate System: Latitude, Longitude, Elevation (m) on WGS84 Datum.
Note: Elevation must be in meters but user can select Feet if required during import to use feet in the software.


Shape Files (.shp and associated files - .shx and .dbf)

Format: point shape file

Feedback and Knowledge Base