Smoothing Lidar Data

Rachael Hay · Post by **Rachael Hay** » Tue Apr 23, 2013 1:05 pm

Hi there,
Just wondering if there's a process for smoothing contours in 12d. I have tiles of data in .xyz format that i'm importing into 12d. Have tried the vertex filter to weed out points but am still not getting nice smooth contours. Am looking for another way to do it. Thanks,

Rachael Hay
Proteus EPCM Engineers

Scott McKinnon · Post by **Scott McKinnon** » Tue Apr 23, 2013 1:09 pm

I gather you're creating contours via TIN - Contours - Coutour, Smooth & Label?

First tab in the dialogue box ('Contours') there's a 'smooth' box to flag.

Rachael Hay · Post by **Rachael Hay** » Tue Apr 23, 2013 1:21 pm

yeah i have this checked but hasn't made a real difference. There may not be another way to do this but wanted to check if anyone knew.
Thanks

Ed Wilson · Post by **Ed Wilson** » Wed May 15, 2013 12:05 pm

I think that contour smooth ticbox did nothing much on lidar data becuase the numberr of points (trias) is massive so mathematically doing some averaging over many points close together doesnt do much.

Using v10 I expect (well think) that one of the grid tin options would do what you want

Owen Thornton · Post by **Owen Thornton** » Wed May 15, 2013 2:55 pm

The smooth tick-box works by creating data (extra vertices on the contour strings), whereas I think Rachael is looking to smooth by removing noise from the source data.

As Ed has already said, the Grid Tin could well offer a good solution here, as (if I recall correctly) it samples the data around each grid point.

Edit: I appear to have recalled incorrectly. The grid tin does not currently sample the data around each grid point.

louren cohen · Post by **louren cohen** » Wed Mar 05, 2014 7:27 pm

I am also confused how we can smooth the contours in 12d. I am a new user here and just learning things. Can any of you guys share me a link to get the manual; I guess a manual can make things easier.

Thanks
LOURENE

Matthew Monk · Post by **Matthew Monk** » Thu Mar 06, 2014 4:55 am

You can get the basic training manuals from the 12d website- http://12d.com/aus/resource_portal/lear ... mentation/

You can also find some videos on the Youtube channel:

The official 12d channel:
http://www.youtube.com/user/12dModelSoftware

A channel by a 12d distributor, EXDS:
http://www.youtube.com/user/12dTrainer

Although, none of those actually cover the smoothing of contours. For V10, you can create a grid tin upon import or create a grid of points (Tins->Utilities->Grid DTM) as previously mentioned.

david owens · Post by **david owens** » Tue Mar 11, 2014 3:11 pm

Hi everyone,
Where i work at Brisbane City Council we have a macro that filters the noise out of Lidar data and dramatically reducing the size of the finished tin while at the same time keeping the integrity of the data as much as possible.

The side effect is that contours produced from the filtered data are a good bit smoother than what you will get out of raw lidar data.

We are happy to email a copy of it if anyone is interested

Matthew Monk · Post by **Matthew Monk** » Tue Mar 11, 2014 11:36 pm

David- does your macro do anything different to the grid points/grid tin options available when importing?

david owens · Post by **david owens** » Wed Mar 12, 2014 9:13 am

it sure is different
the way it works is that it drapes strings over the original lidar tin
then filters them
you then make a tin out of the filtered data
the filter tolerance and sampling rates are user definable but the defaults generally work well
i can email it to you or whoever else wants it

we checked the results by doing tin to tin volume calcs
then comparing the volume to the area of the tin

i am getting differences less than 0.1% and when you consider that lidar data is generally less accurate than that in the first place.....

Glenn Allen · Post by **Glenn Allen** » Thu May 22, 2014 11:18 am

Hi David, I'd certainly be interested in your macro if you are able to provide a copy. I've tried filtering the input data by z to drop out points that are within say 0.05m of a set interval, but haven't had success.
cheers,
Glenn

david owens · Post by **david owens** » Fri May 23, 2014 8:15 am

no worries
can i get your email address?

Glenn Allen · Post by **Glenn Allen** » Fri May 23, 2014 9:35 am

Thanks for the reply David, I have emailed you my contact details.
cheers,
Glenn

Marc Jaspers · Post by **Marc Jaspers** » Mon May 04, 2015 9:52 am

thanks for the heads up on the Tin Grid command, fixed a little problems pretty well

Alexander Todd · Post by **Alexander Todd** » Wed Nov 16, 2016 8:09 am

Hi, is the offer of this Lidar filtering macro still available?

We have a few drone survey point clouds that i would be good to smooth out the contours from a presentation point of view?

Alternatively are there any new options in 12d V12 that i am not aware of yet?

Cheers
Alex