Discussion in 'Tracks' started by Wurstkoffer, Sep 17, 2017.
Ah, this is good news! I was just looking for info on reading geotiff files....
Now here's a challenge... I've found a source for lidar data for the entire Isle of Man. My Snaefell Mountain Course track might be due for a major update... I'll open a new thread here once I have some more details and can have a good look at the data.
So now I'm working on a plugin for RTB to read the data directly. So far the main problem is reading in the colossal amount of data... Each block is 4000 x 4000 points covering 2km square (50cm resolution) and anything up to 400MB each, and there are 188 of them at the last count.
making progress at all Les ?
Hey, good to hear from you!
Yeah, progress, not bad at all. I've got a test app which figures out the right data file to open, and reads out the height data correctly. Just finished running through another conversion of the source files into the right format, this time to 3 decimal places (mm), rather than 17 (!) originally. I eventually worked out it was QGIS that was doing that in the conversion process.
A few things still to do:
Work out how to do some simple error checking (if a data file doesn't exist for example). I'm starting from scratch learning C#...
Figure out how to do some data caching, though I'll probably skip that to begin with and cope with how slow it'll be, at least when starting a new project.
Still to try building the prototype into the RTB template and see what happens (or doesn't)
In the meantime I'm already thinking about how to make it more generically compatible with other data I already have. In theory any UK data should work...
how do you deal with trees though ?
btw..Remember way back and you could extend the coverage of the project in general, can you still do that in a plugin ?
Hmmm, not sure what you mean about trees... this just handles terrain data. Everything works as normal in RTB, only difference is where the height numbers are coming from.
Probably means the difference in DTM and DSM data? One is just terrain.... the other is everything including trees.
Ah, okay! I'll be using DTM, although DSM is also available. I tend to think dtm is more relevant for generating terrain although the post processing that gets used for removing stuff can be hit or miss. I'd still rather not have to do it myself...
yeah, you dont want that trees data. i was under assumption the uk data in high resolution was just the basic all in one. i know there will be older simple terrain data etc....yeah filtering it in any way would be just futile. so there is hi res basic terrain available for this malarkey ? very out of touch with most stuff at the moment I am. and the memory is a sieve
From the UK website I used, there is both available.
so DTM is terrain and DSM is surface data... feel silly not knowing that, was it always there ?
Yes, both types are available as well as point cloud. I've just noticed there's a phase 3 for scotland that I didn't know about. In serious danger of getting sidetracked now...
Lots of east lothian and borders... Jim Clark rally time!
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