set_functions: Set functions

In segmetric: Metrics for Assessing Segmentation Accuracy for Geospatial Data

Set functions

Description

These functions compute subsets required to calculate segmentation metrics as described in Clinton et al. (2010) and Costa et al. (2017).

• sm_ref() returns the set of n polygons of reference, represented by X = \{x_{i}: i = 1, ....., n\}

• sm_seg() returns the set of m segmentation polygons, represented by Y = \{y_{j}: j = 1, ....., m\}

• sm_ytilde() returns \tilde{Y}_{i}, a subset of Y, where \tilde{Y}_{i} = \{y_{j}: \rm{area}(x_{i} \cap y_{j}) \neq 0\}

• sm_xtilde() returns \tilde{X}_{j}, a subset of X, where \tilde{X}_{j} = \{x_{i}: \rm{area}(y_{j} \cap x_{i}) \neq 0\}

• sm_yprime() returns Y'_{i}, a subset of Y, where Y'_{i} = \{y_{j}: max(\rm{area}(x_{i} \cap y_{j}))\}

• sm_xprime() returns X'_{j}, a subset of X, where X'_{j} = \{x_{i}: max(\rm{area}(y_{j} \cap x_{i}))\}

• sm_ya() returns Y\!a_{i}, a subset of \tilde{Y}_{i}, where Y\!a_{i} = \{y_{j}: \rm{centroid}(x_{i}) \:\rm{in}\: y_{j}\}

• sm_yb() returns Y\!b_{i}, a subset of \tilde{Y}_{i}, where Y\!b_{i} = \{y_{j}: \rm{centroid}(y_{j}) \:\rm{in}\: x_{i}\}

• sm_yc() returns Y\!c_{i}, a subset of \tilde{Y}_{i}, where Y\!c_{i} = \{y_{j}: \rm{area}(x_{i} \cap y_{j}) / \rm{area}(y_{j}) > 0.5\}

• sm_yd() returns Y\!d_{i}, a subset of \tilde{Y}_{i}, where Y\!d_{i} = \{y_{j}: \rm{area}(x_{i} \cap y_{j}) / \rm{area}(x_{i}) > 0.5\}

• sm_ystar() returns {Y}^{*}_{i}, where {Y}^{*}_{i} = Y\!a_{i} \cup Y\!b_{i} \cup Y\!c_{i} \cup Y\!c_{i}

• sm_ycd() returns Y\!cd_{i}, where Y\!cd_{i} = Y\!c_{i} \cup Y\!d_{i}

• sm_ye() returns Y\!e_{i}, a subset of \tilde{Y}_{i}, where Y\!e_{i} = \{y_{j}: \rm{area}(x_{i} \cap y_{j}) / \rm{area}(y_{j}) = 1\}

• sm_yf() returns Y\!f_{i}, a subset of \tilde{Y}_{i}, where Y\!f_{i} = \{y_{j}: \rm{area}(x_{i} \cap y_{j}) / \rm{area}(y_{j}) > 0.55\}

• sm_yg() returns Y\!g_{i}, a subset of \tilde{Y}_{i}, where Y\!g_{i} = \{y_{j}: \rm{area}(x_{i} \cap y_{j}) / \rm{area}(y_{j}) > 0.75\}

Usage

sm_ytilde(m)

sm_xtilde(m)

sm_yprime(m)

sm_xprime(m)

sm_ya(m)

sm_yb(m)

sm_yc(m)

sm_yd(m)

sm_ystar(m)

sm_ycd(m)

sm_ye(m)

sm_yf(m)

sm_yg(m)

Arguments

m	A segmetric object.

Value

• sm_ref(): Return an object of class ref_sf (inherited from sf) containing identification (ref_id) and geometry (geometry) columns.

• sm_seg(): Return an object of class seg_sf (inherited from sf) containing identification (seg_id) and geometry (geometry) columns.

• sm_ytilde(), sm_xtilde(), sm_yprime(), sm_xprime(), sm_ya(), sm_yb(), sm_yc(), sm_yd(), sm_ystar(), sm_ycd(), sm_ye(), sm_yf(), and sm_yg(): Return an object of class subset_sf (inherited from sf) containing identification (ref_id and seg_id), and geometry (geometry) columns.

References

Clinton, N., Holt, A., Scarborough, J., Yan, L., & Gong, P. (2010). Accuracy Assessment Measures for Object-based Image Segmentation Goodness. Photogrammetric Engineering & Remote Sensing, 76(3), 289–299. doi: 10.14358/PERS.76.3.289.

Costa, H., Foody, G. M., & Boyd, D. S. (2018). Supervised methods of image segmentation accuracy assessment in land cover mapping. Remote Sensing of Environment, 205(December 2017), 338–351. doi: 10.1016/j.rse.2017.11.024.

segmetric documentation built on Jan. 10, 2023, 5:12 p.m.