Questions tagged [grid-metrics]
GridMetrics computes a series of descriptive statistics for a LIDAR data set. Output is a raster (grid) represented in database form with each record corresponding to a single grid cell. GridMetrics is a component of FUSION/LDV software for LIDAR Data Analysis and Visualization.
14
questions
0
votes
0answers
79 views
Define a projection for LAScatalog chunks using the lidR package in R
Using lidR::grid_metrics with a LAScatalog is it possible to use a second projection for the processing "chunks" such that the resulting raster cells align with a raster image (sentinel 2)? ...
2
votes
1answer
32 views
How does gridmetrics handle IF condition in user defined functions?
I noticed a kind of "inconsistency" in the values returned from two user-defined functions. I tested on a tile of 200mx200m to return a raster of pixel size 50m (16 pixels)
In the following ...
7
votes
1answer
177 views
Spatial analysis of classified grid using QGIS
I'm calculation the positional accuracy of linear features using the buffer method and dividing the region using a rectangular grid.
Here follows the vectos to be compared.
The grid cells were ...
-1
votes
1answer
118 views
Grid_metrics fails to create grid_metrics.vrt
I need to obtain the metrics for a denoised normalized dataset. This is part of the code that I am using:
ctg_denoised <- readLAScatalog("G:/NoBackUp/denoised/")
opt_chunk_buffer(ctg_denoised) <...
1
vote
1answer
97 views
Subset a lascatalog point cloud within a function while calculating grid_metrics
I am trying to create subsets of a point cloud based on the ScanAngleRank and compute some metrics for each subset. Then return a stack of values(rasters) for the metric. I modified the rumple index ...
1
vote
1answer
133 views
Eliminating outliers from a normalized LAS file and output as another LAS file
I need to normalize, eliminate outliers and calculate metrics for a big number of .LAS data of a large area by using as much possible the package LidR. The problem comes when I try to run this part of ...
4
votes
1answer
150 views
Keeping name of metrics as band names when using grid_metrics (lidR)
When executing grid_metrics for a normalized LAScatalog the final results are GTiff files where each band corresponds to a metric. The problem is that the band names are "band 01", "band 02", "band 03"...
3
votes
2answers
297 views
Calculation of density metric of 0.75 height quantile based on Airborne LiDAR Scanning point cloud data by lidR package [closed]
This is a piece of code that I wrote:
metrics<-function(z){Q75=quantile(z,probs=c(0.75))
aboveq75=sum(z>Q75)
dh75=aboveq75/length(z)
return(dh75)}
DH75<-grid_metrics(lid,~...
2
votes
1answer
114 views
GridMetrics output does not align with base DTM?
I am trying to derive grid metrics from LiDAR (.las) file using FUSION's GridMetrics tool.
My problem is that the output raster from GridMetrics does not align with the base DTM used to run the tool.
...
3
votes
1answer
710 views
Calculating standard metrics in multiple LiDAR files with lidR 2.0
I am porting my existing code to lidR version 2.0 and would like someone to let me know if I am coding efficiently. My objective is:
to process a directory of LAS files
normalize las files
calculate ...
2
votes
1answer
177 views
How to incorporate stdmetrics in gridmetrics function?
I am attempting to feed the lidR gridmetrics function a list of metrics. I can generate the list of metrics within a function (following this example):
myMetrics = function(z, i)
{
metrics = list(
...
1
vote
2answers
155 views
Getting statistics in cross sections at varying heights in LAS files?
I am looking to cross section my forest at varying heights. I have high return LAS data (8 points/m2 and average point spacing of 0.2m) and I am looking to do more than the simple 1, 2, 3 approach of ...
3
votes
1answer
296 views
Memory allocation error encountered when automating gridmetrics in R
I am trying to run Fusion's GridMetrics from R, I wrote this for one las file:
#First set up directories to keep the raw data
#separate from that produced by the analysis, Input (.las) and (.dtm),
#...
7
votes
2answers
610 views
Are PDAL or PCL capable of producing LiDAR grid metrics?
I typically use Windows-based FUSION to generate grid metrics, which can be used to describe forest structural characteristics. From the FUSION documentation:
GridMetrics computes a series of ...
