When creating an input file for STAR*NET, users can assign a coordinate as "fixed" by including an exclamation mark after the coordinates as in the examples below:
C 6 909571.954000 1640300.448000 ! ! 'sta irs#5
C 7 909246.199000 1640065.940000 ! ! 'sta irs#5
You can expect that the coordinates for these points will not change in your final pts output file.
But inline options can change this:
Inline options are items inserted in the dat file with a "." prefix. As the dat file is read from top to bottom in the program, they can command the program to perform certain actions at that point in the computation. The position of the inline option can affect your results.
For example, the inline option ".Units FeetInt" commands the program to automatically convert data that follows from International Feet to the unit specified in the Project Options:
.Units FeetInt
.Units DMS
.Order AtFromTo
.Sep -
.Delta Off
.2D
C 6 909571.954000 1640300.448000 ! ! 'sta irs#5
C 7 909246.199000 1640065.940000 ! ! 'sta irs#5
C 39 913901.426600 1639421.597860 ! ! 'sta irs#3
C 40 914308.876000 1639144.663000 ! ! 'sta irs#3
C 25 909882.732680 1640430.102660 ! ! 'sta irs#3
C 11 908970.756920 1639032.401070 ! ! 'sta spk
C 12 909138.562410 1638989.038770 ! ! 'sta spk
C 289 914440.280650 1643438.770030 ! ! 'cmf #592
If the Project Options units were set as Metres or US feet, all the fixed coordinates being read in the "C" records that follow will be converted, and appear as though they have changed.
How do you get around this?
Remember that inline options are applied in the order that they appear. So it is simple to modify the above example to prevent the conversion by moving the entry:
.Units DMS
.Order AtFromTo
.Sep -
.Delta Off
.2D
C 6 909571.954000 1640300.448000 ! ! 'sta irs#5
C 7 909246.199000 1640065.940000 ! ! 'sta irs#5
C 39 913901.426600 1639421.597860 ! ! 'sta irs#3
C 40 914308.876000 1639144.663000 ! ! 'sta irs#3
C 25 909882.732680 1640430.102660 ! ! 'sta irs#3
C 11 908970.756920 1639032.401070 ! ! 'sta spk
C 12 909138.562410 1638989.038770 ! ! 'sta spk
C 289 914440.280650 1643438.770030 ! ! 'cmf #592
.Units FeetInt
Now the fixed corrdinates will be unchanged. Any data read after the ".Units" entry will be converted, so you may wish to delete the entry if no conversion is required.
For more information on dat files and inline options please refer to the chapter on "Preparing Input Data" in the PDF Reference Manual installed with your copy of MicroSurvey STAR*NET.
James Johnston
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