A walk through tunnel - Survex syntax
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This section summarizes the synatx of survex datafile.
See {Tu06b} for more details.
Survex datafiles are text files with command lines and data lines. A command line begins with a keyword, a word which starts with an asterisk "*". The data lines contain the survey data. Comments are supported. A comment begins with a semicolon, ';', and goes to the end of the line. Furthermore extra data on a data line are ignored.
Station names are referred in a namespace in which the left entry is the most general, and the right entry is the name of the station. For example, lost_cave.main_passage.14 is the full name of the station 14 in the survey main_passage of the cave lost_cave.
A survex datafile starts with a "*begin survey_name" command and ends with a "*end survey_name" command. Both commands take the name of the survey, which must be the same.
Here are some survex commands.
- *data. It specifies the order of the survey data on the data lines that follow. For example, *data normal from to length clino compass states that the data have normal style, and you have to insert the survey data in the following order: from_station, to_station, distance, inclination, and compass measurements. A data line following this command might look like 1 2 4.30 17 217: this is the shot 1-2 of 4.3 meters, 17 degrees of inclination, and 217 north</nowiki>
- *entrance states that a station is an entrance. For example *entrance 1 states that station 1 is a cave entrance.
- *equate defines the equivalence of two stations (possibly from different surveys). For example *equate 1 main_passage.14 defines that the station 14 of the survey main_passages coincides with the station 1 of the current survey.
- *include is used to include other survex datafiles. For example "*include main_passage.svx" includes the survex data file main_passage.sxv.
- *export lists the stations referable from other surveys. For example, survey main_passage should have the command *export 14 to make the station 14 referable in an "*equate" command of other surveys. Or the global datafile can have the command "*export main_passage.14" before (or after?) including the datafile of the survey main_passage.
- *fix specifies the geographical coordinates of a station. For example "*fix 1 ..." TODO
- *units specifies the units used for a measure. For example, *units length 0.01 meter states that lengths are expressed in units of centimeters (0.01 m). Another example: *units compass grad states that compass readings are in centesimal degrees.
- *team specifies the name of a survey team member, and optionally his/her roles. For example. "*team xyz compass clino" states that "xyz" was at the compass and clino readings.
Here is a simple example, the first survey file of the sample
cave used in these chapter. Only the first few data lines
have been included. Notice the "*export" command, that makes the
station "24" available to join with other surveys.
*begin gm-01 *export 24 *units length metres *title "Grazie Mille" *team "L. Aimar" compass clino *team "A. Premazzi" notes pictures *team "S. Vandone" tape *team "A. Venturini" tape ; Cap 1 = ingresso *entrance 1 *data normal from to length clino compass 1 2 5.70 -52 190 2 3 6.50 -50 205 3 4 2.80 -90 0 4 5 3.65 -50 193 5 6 4.35 -33 228 ... *end gm-01
Here is the global survex file that includes the three survey files
and joins the surveys with "*equate" commands:
*begin gm *data normal from to tape compass clino ignoreall *units length metres *calibrate tape 0.0 *units compass degrees *calibrate compass 0.0 *units clino degrees *calibrate clino 0.0 ;end generated presettings *equate gm-01.24 gm-02.1 *equate gm-02.13 gm.03.1 *include gm-01/gm-01.svx *include gm-02/gm-02.svx *include gm-03/gm-03.svx *end gm
