我有一个时间序列dt（时间，经度，值），由204行和19列组成。
我想使用raster和oceanmap包将时间序列绘制为栅格图。
我正在尝试将数据帧转换为栅格，但是存在一些问题
这是我的代码：
library(raster)
dt <- t(data.table::data.table(tb)) #tb is the previous matrix with values
rownames(dt) <- tm.mtx #my time as Dates
colnames(dt) <- cdt #lat coordinates
dt[is.nan(dt)] <- NA
dt.melt <- reshape2::melt(dt, id=c(row.names(dt)))
spg <- dt.melt
colnames(spg) <- c("x","y","z")
coordinates(spg) <- ~ x + y
它返回此：
.local（obj，...）中的错误： 无法从非数值矩阵得出坐标
我知道我必须将日期转换为数字，所以：
rownames(dt) <- tm #vector of time in seconds from "2002-08-15"
dt.melt <- reshape2::melt(dt, id=c(row.names(dt)))
spg <- dt.melt
colnames(spg) <- c("x","y","z")
coordinates(spg) <- ~ x + y
gridded(spg) = T
返回：
建议的最小公差：0.107308
points2grid中的错误（点，公差，舍入）： 维度1：坐标区间不是恒定的
从这里我不知道该怎么办。 我在下面附上一些部分数据
head(dt)
-46.4375070233063 -46.4791737000479 -46.5208403767895 -46.5625070535311
2002-08-15 0.1736002 0.1750216 0.1732153 0.1774634
2002-09-15 0.1544965 0.1651486 0.1691601 0.1751704
2002-10-15 0.1882919 0.1835454 0.1881429 0.1941372
2002-11-15 0.2535837 0.2623392 0.2630876 0.2709922
2002-12-15 0.2187145 0.2208886 0.2157844 0.2170794
2003-01-15 0.1413760 0.1334794 0.1383164 0.1370846
-46.6041737302728 -46.6458404070144 -46.687507083756 -46.7291737604976
2002-08-15 0.1773711 0.1833218 0.1922676 0.1941034
2002-09-15 0.1771452 0.1796460 0.1761335 0.1702302
2002-10-15 0.1968857 0.2063893 0.2040608 0.1979190
2002-11-15 0.2707081 0.2532419 0.2730597 0.2807892
2002-12-15 0.2154748 0.2144032 0.2160844 0.2267726
2003-01-15 0.1385788 0.1351013 0.1375451 0.1544153
-46.7708404372393 -46.8125071139809 -46.8541737907225 -46.8958404674641
2002-08-15 0.1936037 0.1870466 0.1829850 0.1970123
2002-09-15 0.1650944 0.1764924 0.1801598 0.1772189
2002-10-15 0.1889605 0.1884651 0.1911619 0.1967313
2002-11-15 0.2862864 0.3205168 0.3466025 0.3267133
2002-12-15 0.2262225 0.2184253 0.2562738 0.2705393
2003-01-15 0.2592504 0.3460798 0.4375293 0.5184022
-46.9375071442058 -46.9791738209474 -47.020840497689 -47.0625071744306
2002-08-15 0.2062590 0.2063133 0.2125093 0.2129866
2002-09-15 0.1775195 0.1759667 0.1642771 0.1685364
2002-10-15 0.2002673 0.1997982 0.1997716 0.1917371
2002-11-15 0.2311774 0.3478559 0.3199840 0.3296006
2002-12-15 0.3308617 0.3285339 0.5459298 0.6657989
2003-01-15 0.6338662 0.6308048 0.5857707 0.4804939
-47.1041738511723 -47.1458405279139 -47.1875072046555
2002-08-15 0.2157603 0.2188090 0.2243740
2002-09-15 0.1742391 0.1754706 0.1729936
2002-10-15 0.2043249 0.2011236 0.2345921
2002-11-15 0.3316522 0.3430276 0.3336774
2002-12-15 0.6513002 0.5746747 0.4276562
2003-01-15 0.4010864 0.4328661 0.4627818
tm
[1] 1 2678401 5270401 7948801 10540801 13219201 15897601 18316801
[9] 20995201 23587201 26265601 28857601 31536001 34214401 36806401 39484801
[17] 42076801 44755201 47433601 49939201 52617601 55209601 57888001 60480001
[25] 63158401 65836801 68428801 71107201 73699201 76377601 79056001 81475201
[33] 84153601 86745601 89424001 92016001 94694401 97372801 99964801 102643201
[41] 105235201 107913601 110592001 113011201 115689601 118281601 120960001 123552001
[49] 126230401 128908801 131500801 134179201 136771201 139449601 142128001 144547201
[57] 147225601 149817601 152496001 155088001 157766401 160444801 163036801 165715201
[65] 168307201 170985601 173664001 176169601 178848001 181440001 184118401 186710401
[73] 189388801 192067201 194659201 197337601 199929601 202608001 205286401 207705601
[81] 210384001 212976000 215654401 218246401 220924801 223603201 226195201 228873601
[89] 231465601 234144001 236822401 239241601 241920001 244512001 247190401 249782401
[97] 252460801 255139201 257731201 260409601 263001601 265680001 268358401 270777601
[105] 273456001 276048001 278726401 281318401 283996801 286675201 289267201 291945601
[113] 294537601 297216001 299894401 302400001 305078401 307670401 310348801 312940801
[121] 315619201 318297601 320889601 323568001 326160001 328838401 331516801 333936001
[129] 336614401 339206401 341884801 344476801 347155201 349833601 352425601 355104001
[137] 357696001 360374401 363052801 365472001 368150401 370742401 373420801 376012801
[145] 378691201 381369601 383961601 386640001 389232001 391910401 394588801 397008001
[153] 399686401 402278401 404956801 407548801 410227201 412905601 415497601 418176001
[161] 420768001 423446400 426124800 428630400 431308800 433900800 436579200 439171200
[169] 441849600 444528000 447120000 449798400 452390400 455068400 457747200 460166400
[177] 462844800 465436800 468115200 470707200 473385600 476064000 478656000 481334400
[185] 483926400 486604800 489283200 491702400 494380800 496972800 499651200 502243200
[193] 504921600 507600000 510192000 512870400 515462400 518140800 520819200 523238400
[201] 525916800 528508800 531187200 533779200