There are various compulsory operations when entering cross-section data. One of them is to select the horizontal alignment. If it is not selected, the cross-sections cannot be obtained.
Additionally, if the digital model is not defined and no layer to cut or section or grid file has been selected, the “Layers not selected” error is displayed. Another possible error consists of not having found objects cutting the horizontal alignment. In this case, the error warning “No intersections found" is displayed
After all the data is entered in the dialog box, the program proceeds to draw all the cuts proposed (if the relevant option is activated) and information about the operation’s progress is provided as a percentage. It then reminds one of the names of the file generated with a .TRA extension, in the project directory.
All the layers selected that are not visible will be reused and activated before this process begins, which is why it may be necessary to regenerate the drawing. If only the digital model is going to be cut, this is not necessary.
During the calculation process, heights are obtained from drawing objects and interpolating when necessary. There is also the possibility of cutting break lines even though they have been drawn on the plan. If the Draw Break Lines in 3D option of the Surface Configuration command in is not activated, the program assigns to each vertex the value of the point height coinciding with it.
Example: DEMO.TRA
|
0.000
|
8.161
|
353.710
|
EDGE
|
|
20.000
|
-20.000
|
349.645
|
End
|
|
20.000
|
0.000
|
349.740
|
Horiz.Alignment
|
|
20.000
|
4.523
|
349.761
|
EDGE
|
|
20.000
|
6.617
|
349.793
|
FILL
|
|
20.000
|
20.000
|
355.187
|
End
|
|
40.000
|
-20.000
|
348.534
|
End
|
|
40.000
|
-12.554
|
348.554
|
EDGE
|
|
40.000
|
0.000
|
347.363
|
Horiz.Alignment
|
|
40.000
|
16.932
|
345.757
|
EDGE
|
|
40.000
|
20.000
|
346.132
|
End
|
|
58.555
|
-20.000
|
341.677
|
End
|
|
58.555
|
-6.587
|
332.850
|
STREAM
|
|
58.555
|
0.000
|
336.672
|
Horiz.Alignment
|
|
58.555
|
11.363
|
343.267
|
EDGE
|
|
58.555
|
20.000
|
345.536
|
End
|
|
60.000
|
-20.000
|
339.701
|
End
|
|
60.000
|
-7.366
|
332.476
|
STREAM
|
|
60.000
|
0.000
|
336.680
|
Horiz.Alignment
|
|
60.000
|
11.480
|
343.232
|
EDGE
|
|
60.000
|
20.000
|
345.496
|
End
|
|
80.000
|
4.402
|
342.500
|
EDGE
|
The file format consists of one line for each intersection found. The following appear on each line: station (taking the initial station into account), distance to the horizontal alignment (negative or positive, depending on whether it is to the left or the right of the horizontal alignment), the height of the terrain at that point and the name of the layer cut. This file can be drawn directly with the Draw Cross-Sections option.
In the aforementioned fragment of cross-sections made from a digitized cartography drawing, cuts with objects situated on different layers (fourth column) can be seen. Analyzing the stations, one can deduce that a distance of 20 m between profiles has been used and that the unique points have been included (station 58.555).
One can likewise observe that the Interpolate option has been used for the cuts. This can be seen because the observation “End” appears at the ends of each cut and because their heights are interpolated from the closest intersections. If the digital model had been defined, these heights would have been obtained from it whenever possible. When a profile is incomplete (there are only cuts on one side of the horizontal alignment), it is shown by an asterisk located in the first column of the line, so that the user can easily detect and correct such situations by editing the file or modifying the digital model. It can also be seen that the program always includes a line having the horizontal alignment’s height for each cut, which is interpolated from the adjacent heights.
TcpMDT