patches() returns unexpected results

[Nowosad]

I tried to use patches() recently. It works well on the example code from the help file, but returns only one patch on various of my own data. Do I misunderstand the function or is there a bug there?

library(terra)
#> terra 1.5.13
checker_values = rep(c(rep(c(1, 2), 8), rep(c(2, 1), 8)), 8)

checker_map = rast(ncol = 16, nrow = 16, resolution = 1,
                   xmin = 0, xmax = 16, ymin = 0, ymax = 16,
                   vals = checker_values)

plot(checker_map)

plot(patches(checker_map))

^{Created on 2022-01-20 by the reprex package (v2.0.1)}

Session info

sessioninfo::session_info()
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#>  date     2022-01-20
#>  pandoc   2.14.0.3 @ /usr/libexec/rstudio/bin/pandoc/ (via rmarkdown)
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#> ─ Packages ───────────────────────────────────────────────────────────────────
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#> ──────────────────────────────────────────────────────────────────────────────

[rhijmans]

patches detects patches (connect cells that have any value) surrounded by NA (or zero). You assume that it detects patches of cells surrounded by cells with any other value. That is not unreasonable. I will have look.

[georod]

Perhaps a related issue. Is this the correct behaviour when using directions=8? I was expecting 1, 2 and 4 to be one single big patch directions=8 (last plot). The same with 7 and 8. The function behaves as I expected when directions=4. I am using terra version 1.3.22. (Update: terra 1.5.17 is now working as expected. Thanks.)

library(terra)

val1 <- c(c(0,1,0,1,1,1,0,1,0,0,1,0,0,1,0,0),
          c(1,1,0,0,0,0,0,0,1,1,0,0,1,1,0,0),
          c(0,1,1,0,0,0,0,0,1,1,0,0,1,0,0,0),
          c(0,0,0,1,0,0,0,1,1,0,0,0,0,1,1,1))

r1 <- rast(ncol = 8, nrow = 8, resolution = 1,
                    xmin = 0, xmax = 8, ymin = 0, ymax = 8,
                    vals = val1)
plot(r1)

r2 <- patches(r1, directions=4, zeroAsNA=TRUE)
plot(r2, main= "directions=4")
text(r2, halo=FALSE)

r3 <- patches(r1, directions=8, zeroAsNA=TRUE)

plot(r3, main= "directions=8")

text(r3, halo=FALSE)

[aloboa]

Please open and modify as suggested by Nowosad, it would be much more useful.