我有一个已知的纬度/经度坐标列表，我需要在纬度/经度网格中找到它们并拉出相邻的数据。我的已知纬度/经度坐标位于数据框中：
LatLong <- structure(list(Lat_orig = c(-55.417, -55.417, -55.417, -55.417,
-55.417), Long_orig = c(-69.58, -69.249, -69.0831, -69.417, -69.749
), Lat_new = c(NA, NA, NA, NA, NA), Long_new = c(NA, NA, NA,
NA, NA), Jan = c(NA, NA, NA, NA, NA), Feb = c(NA, NA, NA, NA,
NA), Mar = c(NA, NA, NA, NA, NA), Apr = c(NA, NA, NA, NA, NA),
May = c(NA, NA, NA, NA, NA), Jun = c(NA, NA, NA, NA, NA),
Jul = c(NA, NA, NA, NA, NA), Aug = c(NA, NA, NA, NA, NA),
Sep = c(NA, NA, NA, NA, NA), Oct = c(NA, NA, NA, NA, NA),
Nov = c(NA, NA, NA, NA, NA), Dec = c(NA, NA, NA, NA, NA)), .Names = c("Lat_orig",
"Long_orig", "Lat_grid", "Long_grid", "Jan", "Feb", "Mar", "Apr",
"May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"), class = "data.frame", row.names = c(NA,
-5L))
Lat_orig Long_orig Lat_grid Long_grid Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
-55.417 -69.5800 NA NA NA NA NA NA NA NA NA NA NA NA NA NA
-55.417 -69.2490 NA NA NA NA NA NA NA NA NA NA NA NA NA NA
-55.417 -69.0831 NA NA NA NA NA NA NA NA NA NA NA NA NA NA
-55.417 -69.4170 NA NA NA NA NA NA NA NA NA NA NA NA NA NA
-55.417 -69.7490 NA NA NA NA NA NA NA NA NA NA NA NA NA NA
我有第二个包含网格化全局数据集的数据框。它非常大，但这里有一小块：
Grid <- structure(list(lat = c(-55.417, -55.417, -55.417, -55.417, -55.417
), long = c(-69.75, -69.583, -69.417, -69.25, -69.083), jan = c(8.5,
8.5, 8.4, 8.7, 8.8), feb = c(8.4, 8.5, 8.3, 8.6, 8.8), mar = c(7.3,
7.3, 7.2, 7.5, 7.6), apr = c(5.8, 5.8, 5.7, 5.9, 6), may = c(4,
3.9, 3.7, 4, 4), jun = c(2.7, 2.7, 2.4, 2.7, 2.7), jul = c(2.2,
2.2, 2, 2.2, 2.3), aug = c(2.6, 2.6, 2.4, 2.7, 2.8), sep = c(3.8,
3.9, 3.7, 4, 4.1), oct = c(5.5, 5.5, 5.3, 5.7, 5.8), nov = c(6.6,
6.7, 6.5, 6.9, 7), dec = c(7.9, 7.9, 7.7, 8.1, 8.2)), .Names = c("lat",
"long", "jan", "feb", "mar", "apr", "may", "jun", "jul", "aug",
"sep", "oct", "nov", "dec"), class = "data.frame", row.names = c(NA,
-5L))
lat long jan feb mar apr may jun jul aug sep oct nov dec
-55.417 -69.750 8.5 8.4 7.3 5.8 4.0 2.7 2.2 2.6 3.8 5.5 6.6 7.9
-55.417 -69.583 8.5 8.5 7.3 5.8 3.9 2.7 2.2 2.6 3.9 5.5 6.7 7.9
-55.417 -69.417 8.4 8.3 7.2 5.7 3.7 2.4 2.0 2.4 3.7 5.3 6.5 7.7
-55.417 -69.250 8.7 8.6 7.5 5.9 4.0 2.7 2.2 2.7 4.0 5.7 6.9 8.1
-55.417 -69.083 8.8 8.8 7.6 6.0 4.0 2.7 2.3 2.8 4.1 5.8 7.0 8.2
我需要在LatLong中找到Grid的每个纬度/经度坐标，然后将Grid列jan中的相邻数据拉到dec，将这些放入数据框LatLong中的相应列中。当我手动执行此操作时，我首先找到最近的纬度，然后查看相关的经度以找到最接近的匹配。这会给我一个这样的解决方案：
Lat_orig Long_orig Lat_grid Long_grid Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
-55.417 -69.58 -55.417 -69.583 8.5 8.5 7.3 5.8 3.9 2.7 2.2 2.6 3.9 5.5 6.7 7.9
-55.417 -69.249 -55.417 -69.25 8.7 8.6 7.5 5.9 4 2.7 2.2 2.7 4 5.7 6.9 8.1
-55.417 -69.0831 -55.417 -69.083 8.8 8.8 7.6 6 4 2.7 2.3 2.8 4.1 5.8 7 8.2
-55.417 -69.417 -55.417 -69.417 8.4 8.3 7.2 5.7 3.7 2.4 2 2.4 3.7 5.3 6.5 7.7
-55.417 -69.749 -55.417 -69.75 8.5 8.4 7.3 5.8 4 2.7 2.2 2.6 3.8 5.5 6.6 7.9
请注意，在我的示例中，所有Latitude值都是常量，但这些值在两个数据帧中也有所不同。
有谁知道最好的方法吗？我尝试过使用gdist包中的Imap，我可以找到最近的点，但一次只能找到一个坐标！有没有人知道找到这些点的好方法并将这些数据移动到新的数据框？
答案 0 :(得分：1)
广义问题，一维：
给定一组采样点和一组参考点，如何将点映射到其最近的参考点？
让我们生成一些点和参考点。
set.seed(100)
pp <- sample(0:100, 10, replace = FALSE)
# [1] 31 25 54 5 45 46 77 34 50 15
rr <- sort(sample(0:100, 10, replace = FALSE))
# [1] 19 27 33 39 63 64 73 88 93 100
使用findInterval和中点：
## finds midpoints between reference points
midpoints <- head(rr,-1) + diff(rr)/2
# [1] 23.0 30.0 36.0 51.0 63.5 68.5 80.5 90.5 96.5
## determines which reference interval each sample point falls into
intv <- findInterval(pp, midpoints)
# [1] 2 1 4 0 3 3 6 2 3 0
## index back into reference point to find closest reference point
rr[intv+1]
# [1] 33 27 63 19 39 39 73 33 39 19
对你的纬度和经度做这个，你可以找到合适的点。
要提取剩余的录制数据，请使用merge但要注意浮点错误。）