Wednesday, 8 January 2014

Cogo Points from Text

Very often I come across survey drawings that have AutoCAD blocks and text representing the surveyed points.
If we want to create a surface in Civil 3D from these points we will need to add in the blocks (cross where the point was surveyed in image above) if they have levels. If they have no levels then second best is to add in the text (13.18) if this has a level. (the insertion point of the text wont be at the same location as the surveyed point but the difference this would make for a topo survey would be negligible in most cases). In my case neither has any level information - they are both at zero elevation. There is a workflow available that uses queries in Map 3D to raise the text up the elevation value in the text itself. I am going to show a different approach here using the AutoCAD Data Extraction command to create a csv file which contains the x ,y coordinates of the text and also the contents (elevation). we then import this back into C3D as cogo points.

First isolate all the 'elevation' pieces of text. Then type DATAEXTRACTION. On page 1 of 8 create a new extraction and save it. On 2 accept the defaults and click next. On 3 tick Text or MText - whichever the elevation text is, click next. On 4 on the RHS tick Geometry and Text, on the LH pane tick Contents, Position X & Position Y, click next.
On 5 untick Show Count Column and Show Name Column, click next. On 6 select 'Output to external data file' and choose a save location and file type. Step 7 is skipped if you just export to external file so on 8 just click finish. Job done. You now have a csv file with x,y,z for the survey points (with the point location at the insertion point of the text but close enough for a lot of surveys!)
You can then inport this back into Civil 3D as you would normally and create cogo points from it. One thing to be aware of is the first line of your csv file will be header info so delete this before trying to import into C3D or it will fail.

1 comment:

  1. I get very annoyed when I get this sort of drawing from Flat Earth Surveyors....I don't know how many hours I've wasted getting a 2D drawing into a usable 3D format.

    If most of the level text items are a constant offset from the surveyed point then they can be selected and moved to the correct location.