Where can I find point data in .txt formats?

[Anonymous]

Hi all,

I have been put in charge of improving a session on Civil 3D in an introductory Computer Aided design course, and I need a way to find a bunch of point data sets for individual student projects.  I would like to use data sets of US regions if possible so students can model areas they are personally familiar with.  Does anybody have any idea where I might be able to find some? 

Cheers!

[Neilw_05]

There is little survey data available through public data servers so you would have to contact your local government engineering and public works departments or private consultants and ask if they can provide something to work with.

Aside from that you'd have to consider utilizing digital elevation models (DEMs) available to the public on several GIS data servers. The National Map is a good source. http://viewer.nationalmap.gov/viewer/

The problem you'll have is DEM's are not in text format so you would have to first process them in Map or C3D and then export them to points files. There may be some utilities online or even for Map or C3D that can do that for you.

Also, the National Map DEMs are distributed in NED format which is not recognized by C3D. However all you need to do is look in the NED dataset for a certain file which C3D is able to use to build a surface. A search of the forum on the topic of DEM or NED should get you that info.

[ksorsby]

Not sure about the US but in the UK you can pick up large areas of DTM points for very little money (about £10 for 10 hectares), maybe even free from google or somewhere (USGS?) if accuracy is not an issue.

The way we work here is to bring in the .asc datasets to a surface, show triangles and points, extract points from surface, convert points to cogo points then export cogo points as ENZ to a file and rename the output extension to .txt. For troublesome files, there is a lisp knocking about called ptexport.lsp which directly exports autocad points to a text file.

Either way, you end up with a text file in x,y,z format.

Pretty easy, works a treat.

Kevin

[dgorsman]

Do you have an industry advisory panel?  The members may be willing to share some data from their employers along with other relevant information and experiences which you can use for examples.

[Anonymous]

Thanks for the quick response. I downloaded a few file types from the USGS website including .adf, .img and .flt. Unfortunately, there doesn't seem to have .DEM. When I try importing the .adf file, AutoCAD says it is unable to load the file.

[Neilw_05]

Please review this thread and follow the steps outlined in the opening post.

Be aware that C3D currently is not able to convert the vertical units from meters to feet, so you'll have to live with working in meters for elevations. I have yet to find a solution to that problem.

[drafter1411]

I use to create my own point file. Then I would have the students import them in.

[Neilw_05]

"I would like to use data sets of US regions if possible so students can model areas they are personally familiar with."

How do you propose to do this?

[ksorsby]

Generally, I've found that if you want datasets that are detailed (ie. recognisable) and reasonably large, you'll have to pay for them. We regularly pay 100's of pounds for point files for sites.

Kevin