Attributes
Attributes can be derived using a search radius, or by specifying the number of nearest neighbourse.
| Vertex Attributes | Definitions |
|---|---|
| Eigen Values x3 | λi |
| Elevation | the z value of the vertex |
| Range | distance from the scanner (only applies to spherical datasets |
| Dip | Dip Orientation of the surface |
| Azimuth | Direction of the surface |
| Colinearity | How linear the surface is |
| Coplanarity | How planar the surface is |
| Pole x3 | x,y,z components of the pole vector |
| Sum of eigenvalues | Xλi |
| Omnivariance | (λ1λ2λ3)^(1/3) |
| Eigenentropy | − Xλi ln(λi) |
| Linearity | (λ1 − λ2)/λ1 Linear 1D feature |
| Planarity | (λ2 − λ3)/λ1 planar 2D feature |
| Sphericity | λ3/λ1 Volumetric 3D feature |
| Change of curvature | λ3/(λ1 + λ2 + λ3) |
| Verticality (x2) | − angle(ei, ez) |
| Absolute moment | (x6) 1 |
| Vertical moment | (x2) 1 |
| Number of points | N |
| Average color (x3) | |
| Color variance (x3) |
| Triangle Attributes | Definitions |
|---|---|
| Dip | Dip of the triangle face |
| Azimuth | direction of the trangle face |
| Fisher K Value | K value of the connected triangles |
| Triangle Area | The area of the triangle |
| Max Edge Length | length of the longest edge of the triangle |
| P21 map | An attribute derived from traces - used for fracture intensity |
References
Fernández, O. (2005) Obtaining a best fitting plane through 3D georeferenced data. J. Struct. Geol., 27 , pp. 855-858 https://www.sciencedirect.com/science/article/abs/pii/S0191814105000143
Weinmann, M. ; Jutzi, B. ; Mallet, C. (2013) Feature relevance assessment for the semantic interpretation of 3D point cloud data ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume II-5/W2, 2013, pp.313-318 https://www.isprs-ann-photogramm-remote-sens-spatial-inf-sci.net/II-5-W2/313/2013/isprsannals-II-5-W2-313-2013.pdf
Hackel, T., Wegner, J. D. & Schindler, K. (2016) Fast Semantic Segmentation of 3D Point Clouds with Strongly Varying Density 2016 ISPRS Annual Congress of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Prague, Czech Republic, July 12-19, 2016 https://ethz.ch/content/dam/ethz/special-interest/baug/igp/photogrammetry-remote-sensing-dam/documents/pdf/timo-jan-isprs2016.pdf
Jerome Demantke, Clement Mallet, Nicolas David and Bruno Vallet (2012) DIMENSIONALITY BASED SCALE SELECTION IN 3D LIDAR POINT CLOUDS ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences http://recherche.ign.fr/labos/matis/pdf/articles_conf/2011/laserscanning2011_demantke_final.pdf