Description Usage Arguments Details Value References Examples
This function will calculate trajectories of land cover change using the
Change Vector Analysis in Posterior Probability Space (CVAPS) approach of
comparing posterior probabilities of class membership with an automatically
determined threshold. Areas of no change are coded as -1. A lookup table for
the codes output by chg_traj
can be calculated with traj_lut
.
1 |
chg_mag |
change magnitude |
chg_dir |
change direction |
chg_threshold |
the threshold to use as a minimum when determining change
areas (can use |
filename |
filename to save the output |
overwrite |
whether to overwrite existing files (otherwise an error will be raised) |
... |
additional parameters to pass to rasterEngine |
This function will run in parallel if a parallel backend is registered with
foreach
.
a RasterLayer of change trajectories, with change trajectories
coded as in the lut
output by traj_lut
Chen, J., P. Gong, C. He, R. Pu, and P. Shi. 2003. Land-use/land-cover change detection using improved change-vector analysis. Photogrammetric Engineering and Remote Sensing 69:369-380.
Chen, J., X. Chen, X. Cui, and J. Chen. 2011. Change vector analysis in posterior probability space: a new method for land cover change detection. IEEE Geoscience and Remote Sensing Letters 8:317-321.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | ## Not run:
t0_train_data <- get_pixels(L5TSR_1986, L5TSR_1986_2001_training, "class_1986",training=.6)
t0_model <- train_classifier(t0_train_data)
t0_preds <- classify(L5TSR_1986, t0_model)
t1_train_data <- get_pixels(L5TSR_2001, L5TSR_1986_2001_training, "class_2001", training=.6)
t1_model <- train_classifier(t1_train_data)
t1_preds <- classify(L5TSR_2001, t1_model)
t0_t1_chgmag <- chg_mag(t0_preds$probs, t1_preds$probs)
t0_t1_chgdir <- chg_dir(t0_preds$probs, t1_preds$probs)
lut <- traj_lut(t0_preds$codes$code, t0_preds$codes$class)
t0_t1_chgtraj <- chg_traj(lut, t0_t1_chgmag, t0_t1_chgdir, .5)
# Change areas are coded following the above lookup-table (lut):
plot(t0_t1_chgtraj)
# No change areas are -1:
plot(t0_t1_chgtraj == -1)
## End(Not run)
|
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