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**NAME**

v.outlier- Removes outliers from vector point data.

**KEYWORDS**

vector, statistics

**SYNOPSIS**

v.outlierv.outlierhelpv.outlier[-e]input=nameoutput=nameoutlier=name[qgis=name] [soe=float] [son=float] [lambda_i=float] [thres_o=float] [--overwrite] [--verbose] [--quiet]Flags:-eEstimate point density and distance Estimate point density and distance for the input vector points within the current region extends and quit--overwriteAllow output files to overwrite existing files--verboseVerbose module output--quietQuiet module outputParameters:input=nameName of input vector mapoutput=nameName for output vector mapoutlier=nameName of output outlier vector mapqgis=nameName of vector map for visualization in QGISsoe=floatInterpolation spline step value in east direction Default:10son=floatInterpolation spline step value in north direction Default:10lambda_i=floatTykhonov regularization weight Default:0.1thres_o=floatThreshold for the outliers Default:50

**DESCRIPTION**

v.outlierremoves outliers in a 3D point cloud. By default, the outlier identification is done by a bicubic spline interpolation of the observation with a high regularization parameter and a low resolution in south-north and east-west directions. Those points that differ in an absolute value more than the given threshold from a fixed value, reckoned from its surroundings by the interpolation, are considered as an outlier, and hence are removed. There is a flag to create a vector that can be visualizated by qgis. That means that topology is build and the z coordinate is considered as a category.

**EXAMPLES**

Basicoutlierremovalv.outlier input=vector_map output=vector_output outlier=vector_outlier thres_O=25 In this case, a basic outlier removal is done with a threshold of 25 m.Basicoutlierremovalv.outlier -q input=vector_map output=vector_output outlier=vector_outlier qgis=vector_qgis Now, the outlier removal uses the default threshold and there is also an output vector available for visualizaton in QGIS (http://www.qgis.org).

**NOTES**

This module is designed to work with LIDAR data, so not topology is built but in the QGIS output.

**SEE** **ALSO**

v.surf.bspline

**AUTHORS**

Original version of the program in GRASS 5.4: Maria Antonia Brovelli, Massimiliano Cannata, Ulisse Longoni and Mirko Reguzzoni Updates for GRASS 6: Roberto AntolinLastchanged:$Date:2011-09-2702:02:59-0700(Tue,27Sep2011)$Full index © 2003-2013 GRASS Development Team