Hi,
I would like to calculate kernel areas using kernel.area function from
adehabitat package.
My original coordintes are in latidude/longitude. I suppose that as an
input for the function the coordinates should be in other fomat - I assume
it is UTM coordinates (seeing the example in help, I haven't found more
information about it...). Therefore I converted the lat/long coordinates
and calculated the area for various kernels. The problem is that it gives
me the same area for all levels...
## sample of my data
> dput(xy)structure(list(long = c(-32.73, -32.12, -31.39, -31.02, -32.16,
-32.17, -32.06, -32.32, -32.58, -33.22, -32.85, -33.36, -33.37,
-33.5, -34.76, -35.51, -34.39, -33.27, -32.65, -32.66, -34.41,
-35.79, -34.29, -35.04, -34.67, -33.92, -34.54, -35.79, -34.66,
-34.66, -35.91, -35.78, -38.15, -38.15, -36.89, -35.76, -35.75,
-35.75, -35.62, -37.73, -36.72, -35.84, -36.71, -37.82, -37.06,
-36.05, -36.91, -37.65, -37.51, -37.87, -37.36, -36.97, -38.08,
-38.07, -37.05, -35.91, -35.14, -36.5, -36.48, -36.59, -36.82,
-37.55, -36.16, -36.39, -37.49, -35.35, -35.83, -36.93, -36.66,
-36.64, -36.49, -36.47, -36.45, -36.42, -36.27, -34.75, -34.85,
-35.08, -33.8, -35.28, -35.25, -33.73, -33.7, -34.93, -35.28,
-34, -33.6, -33.57, -33.55, -35.89, -35.99, -36.09, -36.56, -36.54,
-37.13, -38.11, -39.2, -38.93, -38.53, -37.62, -37.35, -37.07,
-36.54, -36.89, -36.74, -37.43, -37.78, -36, -36.1, -35.7, -35.93,
-37.9, -37.5, -35.85, -37.07, -38.8, -38.77, -38.62, -37.72,
-38.82, -38.67, -36.65, -36.37, -35.6, -35.7, -35.43, -35.66,
-36.38, -36.86, -36.84, -34.95, -34.92, -36.65, -36.63, -36.24,
-36.34, -34.95, -35.06, -36.16, -36.52, -36.01, -35.86, -35.47,
-35.21, -34.94, -35.8, -34.54, -34.78, -36.26, -35, -34.74, -35.1,
-34.72, -35.33, -35.32, -35.44, -35.05, -34.67, -35.16, -35.03,
-32.77, -33.02, -31.76, -32.01, -34.38, -34.5, -33.25, -32.37,
-31.37, -31.24, -32.12, -33.12, -33.12, -33.12, -33.62, -32.13,
-31.5, -31.88, -31.01, -30.89, -30.4, -30.53, -31.54, -28.66,
-29.01, -28.87, -29.35, -29.33, -29.31, -30.16, -30.64, -29.74,
-29.47, -29.95, -29.92, -29.53, -29.88, -30.98, -30.58, -31.18
), complat = c(23.04, 20.44, 20.95, 21.12, 18.51, 16.92, 17.13,
16.98, 16.83, 17.73, 18.6, 19.77, 20.26, 20.43, 18.35, 17.56,
20.29, 20.45, 19.38, 19.86, 17.24, 16.8, 20.36, 22.54, 23.78,
23.64, 21.56, 21.99, 24.82, 25.71, 24.02, 22.57, 19.42, 17.01,
18.64, 18.82, 17.01, 16.92, 17.11, 18.97, 22.57, 22.72, 20.29,
20.46, 22.91, 22.31, 19.92, 19.84, 21.03, 21.19, 22.1, 22.26,
20.44, 19.35, 20.29, 20.46, 19.89, 21.54, 22.89, 23.05, 22.51,
22.9, 25.31, 26.11, 25.39, 22.87, 19.99, 20.18, 22, 21.95, 22.13,
22.07, 22.02, 21.98, 22.16, 21.2, 19.04, 19.01, 20.85, 23.06,
24.33, 23.43, 21.62, 22.48, 23.55, 22.21, 21.06, 21.48, 21.46,
22.99, 25.3, 25.48, 25.05, 24.62, 23.98, 24.39, 24.16, 23.31,
23.08, 22.86, 22.42, 22.42, 22.42, 23.08, 23.72, 17.87, 16.19,
18.6, 20.23, 20.48, 20.94, 19.12, 17.47, 18.68, 21.02, 20.59,
19.22, 19.48, 18.8, 16.65, 15.43, 17.92, 19.39, 19.89, 20.63,
21.13, 21.17, 20.75, 20.79, 21.3, 19.7, 17.8, 19.32, 21.27, 21.09,
20.43, 19.28, 17.59, 18.4, 19.7, 18.77, 18.58, 18.38, 18.45,
18.51, 16.76, 15.22, 13.08, 14.8, 18.08, 19.19, 18.49, 17.77,
16.5, 16.02, 15.82, 15.61, 15.41, 16.61, 17.52, 15.35, 11.89,
10.73, 8.28, 11.17, 13.99, 12.85, 12, 12.07, 11.2, 12.23, 12.31,
11.1, 11.18, 11.91, 14.56, 15.61, 14.76, 13.24, 12.34, 11.75,
10.81, 12.28, 13, 13.23, 13.99, 14.48, 14.96, 14.91, 13.55, 13.51,
14.79, 15.78, 14.71, 14.16, 14.38, 15.12, 14.32, 12.99, 11.64
)), .Names = c("long", "complat"), row.names = c("48", "49",
"50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "60",
"61", "62", "63", "64", "65", "66", "67", "68", "69", "70", "71",
"72", "73", "74", "75", "76", "77", "78", "79", "80", "81", "82",
"83", "84", "85", "86", "87", "88", "89", "90", "91", "92", "93",
"94", "95", "96", "97", "98", "99", "100", "101", "102", "103",
"104", "105", "106", "107", "108", "109", "110", "111", "112",
"113", "114", "115", "116", "117", "118", "119", "120", "121",
"122", "123", "124", "125", "126", "127", "128", "129", "130",
"131", "132", "133", "134", "135", "136", "137", "138", "139",
"140", "141", "142", "143", "144", "145", "146", "147", "148",
"149", "150", "151", "152", "153", "154", "155", "156", "157",
"158", "159", "160", "161", "162", "163", "164", "165", "166",
"167", "168", "169", "170", "171", "172", "173", "174", "175",
"176", "177", "178", "179", "180", "181", "182", "183", "184",
"185", "186", "187", "188", "189", "190", "191", "192", "193",
"194", "195", "196", "197", "198", "199", "200", "201", "202",
"203", "204", "205", "206", "207", "208", "209", "210", "211",
"212", "213", "214", "215", "216", "217", "218", "219", "220",
"221", "222", "223", "224", "225", "226", "227", "228", "229",
"230", "11310", "11410", "1154", "1161", "1171", "1181", "1191",
"1201", "1211", "1221", "1231", "1241", "1251", "1261", "1271",
"1281", "1291"), class = "data.frame")
> head(xy) long complat
48 -32.73 23.04
49 -32.12 20.44
50 -31.39 20.95
51 -31.02 21.12
52 -32.16 18.51
53 -32.17 16.92
## create a matrix
xy<- cbind(xy$long, xy$complat)
## convert to UTM coordinates
## my data are widely spread over the central Atlantic
## Ocean, so I think it is not possible to define the "zone"
## needs to be as dataframe for kernelarea
xyUTM<-as.data.frame(project(xy, "+proj=utm ellps=WGS84"))
## calculate kernelarea
kernLevels <- seq(5,95, by = 5)
Karea_xyUTM<- kernel.area(xyUTM,id=NULL, h=1.8, grid=500,
levels = kernLevels,
unin ="m",
unout = "km2")
## the results...
Karea_xyUTM 1
5 4990969904
10 4990969904
15 4990969904
20 4990969904
25 4990969904
30 4990969904
35 4990969904
40 4990969904
45 4990969904
50 4990969904
55 4990969904
60 4990969904
65 4990969904
70 4990969904
75 4990969904
80 4990969904
85 4990969904
90 4990969904
95 4990969904
I wuld appreciate a lot if anyone could check where the error is coming
from.
Thank you,
Zuzana
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