v.ply.rectify - GRASS GIS manual

Note: This addon document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade your GRASS GIS installation, and read the current addon manual page.

NAME

v.ply.rectify - Imports PLY points, georeferences and exports them.

KEYWORDS

vector, import, export, rectify

SYNOPSIS

v.ply.rectify

v.ply.rectify --help

v.ply.rectify [-s] input=name [output=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-s: Also export point cloud shifted to center
--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

input=name [required]: Name of input PLY file
output=name: Default is input name without .ply

DESCRIPTION
EXAMPLE
SEE ALSO
AUTHOR

DESCRIPTION

v.ply.rectify imports a PLY point cloud, georeferences and exports it. The first three vertex properties must be the x, y, z coordinates with property names "x", "y", "z", in this order.

A text file with Ground Control Points (GCPs) must exist in the same folder where the point cloud is located, and the textfile must have the same name like the point cloud, but ending on .txt instead of .ply.

The text file with GCPs must have the following format with one GCP per line:

  x y z east north height status

with x, y, z as source coordinates and east, north, height as target coordinates. The status indicates whether to use a GCP (status is not zero) or not (status is zero). Entries must be separated by whitespace or tabs. Decimal delimiters must be points.

The georecitifictation method used is a 3D orthogonal rectification where angles are preserved. 3D objects are shifted, scaled and rotated, but no shear is introduced. Please read the output of the module, in particular the root mean square (RMS) errors.

v.ply.rectify optionally exports the georeferenced point cloud not only with real coordinates, but also with shifted coordinates (-s flag) for display in meshlab or similar software that can not deal with real coordinates. The exported PLY point clouds will be in the same folder like the input PLY point cloud.

EXAMPLE

With a point cloud file pointcloud.ply and associated control points in pointcloud.txt,

v.ply.rectify -s input=pointcloud.ply

will generate three files: pointcloud_georef.ply with the georeferenced point cloud, pointcloud_georef_shifted.ply with the georeferenced point cloud shifted to the coordinates' center, and pointcloud_rms.csv with the RMS errors of the control points.

AUTHOR

Markus Metz

SOURCE CODE

Available at: v.ply.rectify source code (history)

Latest change: Mon Jun 28 07:54:09 2021 in commit: 1cfc0af029a35a5d6c7dae5ca7204d0eb85dbc55