This week, we tell you all the ways in which you can create L-sections using GT_PROFILE and GT_L-SECTION tools in GeoTools.
There are two commands that directly create an L-section from either a 3dpolyline, or from a set of elevations coming from Excel:
- GT_PROFILE : (GeoTools -> Civil Tools -> Draw cross-sectional pro
- GT_L-SECTION : (GeoTools -> Civil Tools -> Draw cross-sections from Excel data)
And a third related command GT_CS-SCANNER which can help yo build cross sectional 3d polylines from a set of points lying along an alignment.
GT_PROFILE (GeoTools -> Civil Tools -> Draw cross-sectional profile from 3D Polyline)
The GT_PROFILE command is versatile, and we are confident it remains simple and easy to use as well.
The primary input for this command is the humble 3D polyline, with elevations, and you can easily create the cross-sectional profile of the same in elevation view.
You are 1st asked to select the 3D polyline you want to profile. It supports multiple selection of 3D polylines at once as well.
The dialog box above is pertty self-explanatory. You can set the salient parameters like profile interval, annotation interval, reference height, vertical scale factors and so on.
There are 2 main types of annotation – Interpolated and Source.
Interpolated profile creates a profile computation point at the specified interval, and the annotation interval determines where the key annotation interval determines where the key annotations must show up on the profile.
The ability to control whether you want the distances to be measured in slope or horizontal is great because you can control your output precisely as per your design intent.
Here is a list of other key design output paramaters:
- Profile grids can be created to help grasp the elevation and distances easily.
- Bottom annotations also can be easily boxed for presentation.
- Every profile point shown is exported to Excel CSV files also.
- Chainage start can be specified so that multiple sheet profiles can be managed
- Route-names can be assigned, so that layering is easily identified on this basis.
- Inter-chainage difference in elevation is shown for easily imagination of the terrain between 2 profile points.
We wish to grow this tool beyond a standard L-section drawing tool. We want to add more analytics than before. You can now use the GT_PROFILE to get more information from your alignment that was previously imagined.
GT_L-SECTION: (GeoTools -> Civil Tools -> Draw cross-sections from Excel data):
The GT_L-SECTION command is used when you don’t have a 3D-polyline but you have an Excel file already which shows the chainage and elevations in 2 columns.
You can recreate the L-section in the drawing using data from Excel, which may have been created by other applications, or simply available as legacy data.
The 1st step is to carefully copy the data from Excel using Ctrl-C and place the information on clipboard.
You select the data of interest and copy them in clipboard. An example data-set is shown above.
The GT_L-SECTION dialog box allows you to specify the locations of the various design values form Excel. Here, you need to specify the column positions of the chainage, elevation(s) and other information like text height, spacing etc.
A sample output is shown above. This command can be used to create profiles of any length and size by processing data from Excel sheets.
Its best use-case is perhaps when you already receive the chainage and levels information in an Excel file and need to just create a 3D profile out of it. If the Excel file also contains Eastings and Northings, it is not a problem and can be ignored by the program by specifying only the relevant column numbers to process.
Of course, the Easting, Northing and Elevation information can be joined together and imported to create a 3D polyline using the GT_IMPEX command.
GT_CS-SCANNER: GeoTools -> Civil Tools -> Cross-section points scanner
The GT_CS-SCANNER command is a tool that will scan along an alignment and build cross-sectional data (a 3D polyline) from the set of elevation points that are captured in the perpendicular direction to the alignment flow.
As you can see from the dialog box above, there are an elaborate set of parameters that this command can work with. You can specify different layers and entity types for point numbers (text or block attributes) and elevations (point, text or blocks).
The scanning can be done automatically at specified chainage intervals -or- it can also be done manually by picking a point along the alignment.
Please remember to set your corridor thickness (for point scan) correctly, as setting it too low may not capture all the points that may exist in the cross-section.
Sometimes, the cross-section will not be captured in a perpendicular direction because of terrain conditions or other reasons. In this case, there is a provision in this command to try searching for points in a non-orthogonal direction also.
The command will automatically scan around the chainage points for cross-section data and will report to you what it finds. You can accept or reject its suggestion based on what you think is right.
Use-case: This is a great tool for you to build some supplementary data for further design when your consultant has just provided the data in the format that we just mentioned. And this is common scenario in most survey projects in India and possibly elsewhere also.
Upon successful completion of this command run, it will create cross-sectional 3D polylines as shown in the above image.
If you have the chainages (and the intersecting elevation data) appearing consistently, then you can run it in automatic mode -or- you can manually select each chainage and create the cross-section data.
Either ways, this is a huge time-saver where you need it the most.
One Tool, Four Platforms!
GeoTools and CADPower runs on AutoCAD, BricsCAD, ZWCAD and ARES Commander.
You choose your platform. We provide the tools for your automation!