large .img lidar file

[Anonymous]

I am trying to bring in a large .img (65mb) lidar file into Civil 3D without success.  The point cloud creation does not support .img files.

I have tried converting the .img file to an ASC and DEM with a program called FWTools, but after conversion, the import of the ASC or DEM as a point cloud gives a fatal error.  Import of the DEM under a surface in the prospector works, but slows the drawing so much that it is unusable.

Any advice would be appreciated.

[Anonymous]

can you let us know more about your system - win 7 or xp, 32 or 64 bit, video card & how much ram?  May be related,  but 65Mb is pretty substantial.

You might play with something like "MARS" - Merrick Advanced Remote Sensing (a previous employer of mine) to see if it can process the data set.... they have a free trial available online that you could tinker with & maybe export out your AOI

[antoniovinci]

I guess you won't be able to treat Dem files like IMG/ASC as vector point cloud.

Which is the grid width of the original IMG..?
You can check it out with the free Microdem.

[Anonymous]

The img file tile is about 5000m x 5000m with points approximately on a 1m grid.

It appears the MARS 7 program will not import an .img file.

My system:

processor: intel duo CPU E7600 @ 3.06 GHz

RAM: 4GB

32 bit O.S.

video card: NVIDIA GeForce 9300 GE

Windows 7 Professional

Thanks!

Jeff

[Anonymous]

So, a couple of years ago before I upgraded to WIn7/64-bit, i would crash my machine (a dell laptop) trying to load several USGS DEM files - a surface for a 32 mile pipeline across several 'quads.  UPgrading to 64-bit (the machine was a 64-bit processor dummied down to run 32-bit XP due to our IT dept) with the exact same hardware allowed me to build the surface. using some 19 quad maps.

for my weekend work - not using our company's C3D, but for personal consulting, I use Global Mapper - which is much less expensive than C3D / Map3D.  Looks like it can read in a IMG and would be able to re-write the surface model out as a DEM...  but I'd start with going to a 64-bit OS - even if you enabled the 3GB switch, you won't get much further on a large data set under the 32-bit environment...

[Alfred.NESWADBA]

Hi,

Are you sure that the extension .IMG is the correct one for a lidar file?

25mio points should not be that problem, I would try to look into the file with a binary-editor and compare it to formats listed as available formats, then rename the file (the extension) and try to import it within Civil3D-command CREATEPOINTCLOUD.

Good luck, - alfred -

[Anonymous]

I believe that yousendit.com will let you transmit upto a 100mb file - if you post it there and send me a link via private message,  I'd be willing to see if GM can convert  and I happen to have my personal machine here at work today.... send me a private message if you want me to try anything...  kinda twiddling thumbs today while between projects and sounds like a good friday afternoon activity... 😉

[Anonymous]

The data I'm looking at is here.  Its a free signup on the Kansas Geospatial Data Access and Support site.

http://www.kansasgis.org/catalog/index.cfm?data_id=1381&show_cat=5

It looks like global mapper might do it, but not with my trial version.  I'd like to know if it actually can or not before paying for it.  I don't have an ftp site subscription.  Thanks!

Thanks for the advice on the computing power.  I've had success creating a point cloud and surface from .las files, but they are not corrected for trees and buildings as the .img file is.

[Anonymous]

Thanks! may do so - just that I happen to have GM already, so working with what I've got.  But that 4 letter work "Free" is always a draw.... 😉

[Anonymous]

ok. i created an account and downloaded a .zip but it is a .las file - can you point me to a .img for downloading?

[Anonymous]

.img file is the "bare earth" file.

[Anonymous]

.img file is the "bare earth" file.

[Anonymous]

wow, GM read in the 65mb .img in about 1/2 second (literally) and the 387 MB .LAS in about 12 seconds - screamin fast in comparison to what I've done before - I'm impressed with what it can do...

[Anonymous]

Cool. Can you export the .las as a .img? Jeff Murphy, P.E. Staff Engineer Agricultural Engineering Associates Uniontown, KS phone: 620-756-1000

[antoniovinci]

Jeff, I've downloaded the BE_14SNJ9050.IMG bare earth file (70 MB), on my glorious XP 32bit with 2 GB Ram.

When you open it in Microdem, you can:

• SAVE AS "USGS ASCII" which is a .DEM format well loadable in Civil with _MAPCONNECT
  
  
• SAVE AS "XYZ TRIPLES" yielding a beautiful text file, where each line contains the coordinates of every grid point.

I found only one text editor able to open such a monster (~ 25M lines), so if you have a 64 bit system, you can try other ways.

Another nice feature of Dem viewers like Microdem is the contours' generation, but I didn't dare to do that with my poor PC.

[Anonymous]

It looks like MicroDEM uses FWTools for conversion, which I haven't had any luck with. I'm thinking these .img files may be too big to convert. Jeff Murphy, P.E. Staff Engineer Agricultural Engineering Associates Uniontown, KS phone: 620-756-1000