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Unread 17 June 17, 00:44   #53
Wee Scot
Wee Scot's Avatar
Join Date: Jan 2007
Location: Dumfries, Virginia
Age: 62

OK, starting with baby steps...

Ten years ago, when I was working with the early development versions of BTB, I started a new project by placing a JPEG image (which I created in Microsoft Paint by connecting screen captures of several Google Maps satellite images) as my background image, then laying down my "closed loop track" by following the real-life roads in that background image, clicking to add a sufficient number of nodes to accurately trace the exact path those real roads. Then I used the somewhat-accurate elevation data in Google Maps--available by tracing the roads with my mouse cursor--to note the changes in elevation and apply them by hand in BTB.

TODAY, I'm looking to create tracks based on much more accurate elevation data about both the circuit paths and the surrounding terrain.


Now, in BTB Pro, I'm given the following options:

Under File, I can:

Import... > 'Import GPS', under which there are two tabs:

CSV - "Import GPS data. Must be in a very specific format. See your GPS folder for an example. All values are in meters." If you click the Import button, you are instructed to find *.csv files.

Google Earth - "Use Google Earth to create a path and save it to KML format. Then load here." If you click the Import button, you are instructed to find *.kml files.

Under File, I can also:

Import Cloud... > 'Import Point Cloud', which provides columns for X, Y (Height), and Z values, as well as Intensity and Colour values, Delimiter, and an unexplained Filter slider set by default to 100%. If you click the Select Files & Import button, you are instructed to find *.txt or *.csv data files.


The LiDAR data I downloaded through the Earth Explorer (USGS EROS) website consists of nine "tiles" which cover the length of the 9-mile Joplin Road "open track" I want to create, each a small (34 KB) CSV file that contains a lot of latitude and longitude data, in both DMS (degrees, minutes, seconds) and decimal form, arranged as such:
LIDAR Entity ID,Project,State/Province/Country,Pulse and NPS Units,Pulse Density,Nominal Pulse Spacing,Beginning Date,Ending Date,Vendor,Vendor Scene ID,Map Projection,Projection Zone,Datum,Vertical Datum,Center Latitude,Center Longitude,NW Corner Lat,NW Corner Long,NE Corner Lat,NE Corner Long,SE Corner Lat,SE Corner Long,SW Corner Lat,SW Corner Long,Center Latitude dec,Center Longitude dec,NW Corner Lat dec,NW Corner Long dec,NE Corner Lat dec,NE Corner Long dec,SE Corner Lat dec,SE Corner Long dec,SW Corner Lat dec,SW Corner Long dec,Display ID,Ordering ID,Browse Link
An example of the data format:
3832'33.58"N,7725'03.23"W,3832'58.58"N,7725'34 .33"W,3832'58.00"N,7724'31.39"W,3832'08.58"N,77 24'32.14"W,3832'09.16"N,7725'35.06"W,38.542661,-77.4175638,38.5496055,-77.4262027,38.5494444,-77.4087194,38.5357166,-77.4089277,38.5358777,-77.4264054
Now, there doesn't appear to be any height--elevation--data in these files. The only reference I can find that even SUGGESTS height is the 'Vertical Datum' category, which comes just before all the DMS and digital LongLat information. But all the Vertical Datum entries are the same: NAVD88. Does that perhaps refer to a completely DIFFERENT data source, which I have to download separately, but that will be "aligned" with the LongLat information I already have?

The LiDAR data I received through the NOAA Digital Coast Data Team website came to me as a 164 MB zip archive containing four *.laz files, an xml document, and four tiles_index files, with the extensions .dbf, .prj, .shp, and .shx.

EDIT: @Emery-I did as you recommended in our Conversation at Race Department: I used the drawing tool to define a rectangular area that encompassed the two stretches of road--Aden Road and Joplin Road--that I want to use for two short "open" tracks or one longer one. Three "results" were then listed to the right of the map:
NOAA Sea Level Rise DEM
2016 USGS CoNED Topobathymetric DEM Model: Chesapeake Bay (1859-2015)
2012 USGS-FEMA Lidar: Northern Counties (VA-North)
The last result was clearly the one I wanted, but for this one, I was not given the "shopping cart" option to select only the tiles in, or bordering that area I'd defined. My only option was to select Bulk Download.

The email I got in response, however, pointed me to a link to download a 164 MB zip archive, which contained only 4 tiles. As was explained in the email, "This was a large job and was split into 4 tiles for processing."

What do I make of this? What is the procedure for converting LAZ files into a format that can be used by BTB?

I need:

1) Clarification on what to do with the Earth Explorer data, and whether it already has height information in it I'm just overlooking, or whether I need to look elsewhere for that.


2) Step-by-step instructions on what to do with the LAZ files I received from NOAA


2) Information on where ELSE to find a source of terrain data I can use to more easily create real-world terrain in BTB.

Thanks, guys! While I wait for your guidance, I'll be driving my favorite cars on my favorite tracks in GTR2, rFactor, Grand Prix Legends, and GP4!

Last edited by Wee Scot; 18 June 17 at 20:44.
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