Coordinate System - NYS GIS lidar

[salbright38QJG]

I'm trying to use the NYS GIS Clearinghouse data and use Recap to convert so I can bring into C3D. None of the coordinate systems I've tried are bring the .rcp file into the correct place in C3D when I attached the point cloud. I have my C3D coordinate system set to the correct State Plane Coordinate system for my project. The metadata file for the lidar is attached. I've reviewed some of the other forums and it seems like this is a common problem, but I haven't found a good way to confirm what coordinate system Recap is looking for. Any thoughts on what settings I need to use in Recap? 

[ramesh_sridharan]

@salbright38QJG Looking at the bounds in pdf, the data seems to be Lat/long spanning Tiny, ON to Tompkins, NY. Lat/long is usually not a great way to store data in LAS file especially due to rounding off errors. Either try to import as LL84 or get the LAS data in Stateplane.

[salbright38QJG]

Should the current and target both the LL84? If I do this, it still doesn't come in to the correct position on C3D. If I set the Target to my desired State Plan coordinate, I'm getting a 'Could not import scan' error. Not sure if that's a random Recap error, or if it doesn't like my target coordinate system.

[ramesh_sridharan]

Can you try current as LL84 and target as SP (I am assuming that what you have C3D drawing at)?

[salbright38QJG]

I can't set the target to the SP for some reason. I get the error below (could not import scan).  I'm sure I'm doing something wrong on my end, but can't seem to find an option that will overlay my site. 

[ramesh_sridharan]

Can you confirm with your source that the file is indeed in LL84? When you import in ReCap without specifying CS, what XY values do you see? Are they in sync with the bounds specified in the pdf your uploaded?

If you can you send me a sample file, I can try to see.

[salbright38QJG]

All I have from the source is the metadata file I downloaded. When I import into Recap (no coordinate system and LL84), the coordinates are both the same. These points are within the metadata, and correct per Google Earth lat/long and northing/easting. When I check my C3D file for where it should come in (existing survey), these points match with where it's supposed to be. But when I bring in the point cloud, nothing lines up. I can't attach an .las or .rcp file here. So I'm not sure what files would help. 

[Pointdump · Accepted solution]

Hi @salbright38QJG,
Please post your LAS file. This forum will accept any format if you zip. If the file is too large, then use a link to WeTransfer, DropBox, etc.
Your metadata shows the data is in UTM83-18 EPSG:26918.
Dave

[salbright38QJG]

Dave,

Looks like you fixed it! Thank you! When I searched the EPSG you provided I was able to export from Recap and bring the point cloud into C3D correctly. Now for the next question, do did you determine the EPSG from the metadata? I see the UTM 18 on page 5 of the metadata, but I'm not sure how you find the EPSG (just want to make sure I can do the next project correctly).  

[Pointdump]

@salbright38QJG,
They really make you dig for it. Almost halfway down, start reading at "Spatial_Reference_Information:". It tells you the Datum: NAD83(2011). A search in Civil 3D MAPCSLIBRARY shows the EPSG number.
The easier way is to use LASInfo in the free LASTools. Not only will it tell you the coordinate system information, it will also list points by classification: Ground(2), etc...

Dave

[salbright38QJG]

Thanks for all of the info, I really appreciate it!