[GRASS-dev] r.in.lidar: height above ground

[Vaclav Petras]

Hi,

in r66094, I've added base raster map to r.in.lidar. When provided,
r.in.lidar with subtract its values from the points' z values. In this way,
one can get height about ground.

Needs testing before general anouncement, so feel free to do so.

Adding a simple suggestion how to do a benchmark or test.

Vaclav

https://trac.osgeo.org/grass/changeset/66094

PS: Just now I realized that this should have been the commit with word
news or feature or something for automatic extraction.
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> g.region -p
north:      224028.45
south:      223266.45
west:       638557.28
east:       639319.28
nsres:      0.1
ewres:      0.1
rows:       7620
cols:       7620
cells:      58064400

> time r.in.lidar in=points.las out=test_pure
Projection of input dataset and current location appear to match
Reading data ...
 100%
Writing to map ...
 100%
r.in.lidar complete. 948239 points found in region.

real	0m8.088s
user	0m6.888s
sys	0m0.780s

> time r.in.lidar in=points.las out=test_hag_elevation base=elevation
Projection of input dataset and current location appear to match
Reading data ...
 100%
Writing to map ...
 100%
r.in.lidar complete. 948239 points found in region.

real	0m9.759s
user	0m9.084s
sys	0m0.624s
> time r.mapcalc "test_difference = (elevation + test_hag_elevation) - test_pure"
 100%

real	0m15.292s
user	0m23.280s
sys	0m1.172s

> time r.univar test_difference
 100%
total null and non-null cells: 58064400
total null cells: 57140606

Of the non-null cells:
----------------------
n: 923794
minimum: -1.52588e-05
maximum: 1.52588e-05
range: 3.05176e-05
mean: -3.14659e-09
mean of absolute values: 1.36327e-07
standard deviation: 1.02145e-06
variance: 1.04336e-12
variation coefficient: -32462.2 %
sum: -0.00290679931640625

real	0m3.468s
user	0m3.428s
sys	0m0.000s

> time time v.in.lidar in=points.las out=test_plain_import_simple -tb
Scanning 948256 points...
 100%
948256 points imported

real	0m3.384s
user	0m1.416s
sys	0m1.956s

> time time v.in.lidar in=points.las out=test_plain_import_no_topo -b
Scanning 948256 points...
 100%
948256 points imported

real	1m46.292s
user	1m17.748s
sys	0m36.692s

> time v.in.lidar in=points.las out=test_plain_import
Scanning 948256 points...
 100%
Building topology for vector map <test_plain_import at manual>...
Registering primitives...
948256 primitives registered
948256 vertices registered
Building areas...
 100%
0 areas built
0 isles built
Attaching islands...
Attaching centroids...
 100%
Number of nodes: 0
Number of primitives: 948256
Number of points: 948256
...
948256 points imported

real	2m6.593s
user	1m39.080s
sys	0m36.060s