I am interested to find out how others process topographic survey data in ArcGIS. Often I am only given a text file or an Excel spreadsheet containing XYZ points and simple attribute information describing the type of the survey point (Tree line, Fence, Road, etc.).
Depending on the type of project I triangulate or interpolate to create a surface and then generate contours, etc.

I am not an AutoCAD user but several times I have seen data processed in AutoCAD and the results are better. It almost seems as if there was some additional information I am not getting in the "raw" files such as breaklines. I was pretty sure that breaklines also have to surveyed so perhaps I am not getting this data?

I've looked at the Survey Analyst extension but I believe it is mostly for those that maintain parcel data.

Here is an example of a file I usually receive (first 7 of about 300 lines):


It almost seems as if there was some additional information I am not getting in the "raw" files such as breaklines

From the snippet you show, no you don't have any breaklines. With the data you have, I would be doing the exact same process that you are.

AutoCAD will not yield better results if using the same data.

Any chance you could show 2 screenshots of a consistent extent, one done in ArcGIS, one done in AutoCAD?

For info, this 3 part series on the ESRI blog is a good read about processing Topographic (specifically Lidar) data. They discuss both breaklines and how to interpolate the data. Part1 Part2 Part3

  • 2
    Thanks Simon. I hunted down one of the surveyors and I was indeed not dreaming; they design the breaklines by selecting some of the points they have taken using their own knowledge of the terrain or notes. They then incorporate these breaklines into the surface when processing the data in ACADD then deliver dwg files with breaklines but raw data without. I will start asking them to mark the breaklines right on the data logger. Thanks for the links too, i usually have no issues with processing LiDAR but these are definitely informative. – Jakub Sisak GeoGraphics Oct 16 '10 at 0:58

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.