Measurement Files
The measurement files used at the Federal Office of Topography are based on fixed formats, meaning that the various indications and coordinates must be placed in specific columns.
The first line of an LTOP measurement file must begin with $$ME. The rest of the line is a comment.
Each measurement file may contain comment lines, which must begin with **.
txt
$$ME TRIANGULATION 4. ORDNUNG, KANTON AARGAU, LK-BLATT 1089
ST89.345 SCHOEN 7. STATION1B.MEIER 01.01.85
RI89.469 .6 0.00000
RI89.472 .6 86.47140
RI89.472 .6 87.47140
HW89.469 .6 1.47220 1.164 2.000
ZD89.472 .6 98.59200 1.164 2.000
ST89.466 .6 1.464STATION2 02.01.85 5.0
RI89.467 .6 0.00000
RI89.470 .6 40.66420
RI89.469 .2 57.51640 100.0
RI89.469 .6 67.72580
SLS287 YXRMHX-
LY89.466 .6 645366.165
LX89.466 .6 246188.349
LH89.466 .6 442.290
| | | | | | | | | | | | |
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
1 2 3 4 5 6 7 8 9Format of station lines for terrestrial observations
| Character position | Description | |
|---|---|---|
| 1 - 2 | (A2) | Observation type (always ST) |
| 3 - 12 | (A10) | Station name |
| 13 - 16 | (A4) | Station type |
| 25 - 36 | (A12) | Meteorological information |
| 37 - 42 | (F6.x) | General mean error of directions in cc |
| 43 - 46 | (I4) | General distance group |
| 47 - 52 | (F6.x) | Instrument height |
| 53 - 60 | (A8) | Field book (or field computer) |
| 61 - 78 | (A18) | Observer and date |
| 85 - 90 | (F6.x) | Centering error in mm |
Format of lines for terrestrial observations
| Character position | Description | |
|---|---|---|
| 1 - 2 | (A2) | Observation type |
| 3 - 12 | (A10) | Target point name |
| 13 - 16 | (A4) | Target point type |
| 25 - 36 | (F12.x) | Measured value |
| 37 - 42 | (F6.x) | Mean error of observation |
| 43 - 46 | (I4) | Observation group |
| 47 - 52 | (F6.x) | Instrument height |
| 53 - 58 | (F6.x) | Signal height |
| 85 - 90 | (F6.x) | Target centering error in mm |
Format of GPS station lines
| Character position | Description | |
|---|---|---|
| 1 - 2 | (A2) | Observation type (always SL) |
| 3 - 12 | (A10) | Comment |
| 37 - 42 | (F6.x) | Mean error of GPS observations in mm |
| 43 - 52 | (A10) | GPS series name |
Format of GPS observation lines
| Character position | Description | |
|---|---|---|
| 1 - 2 | (A2) | Observation type (only LY, LX or LH) |
| 3 - 12 | (A10) | Point name |
| 13 - 16 | (A4) | Point type |
| 25 - 36 | (F12.x) | Measured coordinate |
| 37 - 42 | (F6.x) | Mean error of coordinate in mm |
List of accepted observation types
| Observation code | Description |
|---|---|
| ** | Comment line |
| ST | Data for a terrestrial observation station |
| SL | Data for a GPS observation station |
| AZ | Astronomical azimuth |
| AP | Bearing in the projection plane |
| RI | Direction measurement in gons |
| RA | Direction measurement in sexagesimal degrees |
| DS | Slope distance |
| DP | Horizontal distance in the projection plane |
| DB | Horizontal distance at the altitude of the target point |
| HW | Vertical angle in gons |
| ZD | Zenith distance in gons |
| HA | Vertical angle in sexagesimal degrees |
| DY,DX,DH | Coordinate differences in the projection plane |
| YY,XX,HH | Coordinates in the projection plane |
| LY,LX,LH | Coordinates determined by GPS |
Source:
Description of the LTOP format, available at the following address: https://geodesy.geo.admin.ch/reframe/ltop_fmt_descr_fr.html