我想过滤掉不在给定BBOX内的坐标。
我有以下GPS点的列表，为了测试这个问题，我知道所有这些都在BBOX内：
V1 V2
1: 47.8924 11.7018
2: 47.81252 12.07387
3: 47.84976 12.08231
4: 47.89307 11.69957
5: 47.8497 12.0824
6: 47.8497 12.08272
7: 47.89152 11.69514
8: 47.88932 11.70749
9: 47.84252 12.11194
10: 47.80853 12.07071
此外，我有以下BBOX：
xmin ymin xmax ymax
11.71541 47.77093 12.32288 48.17883
我知道所有这些点都在BBOX内部。
检查我是否使用了以下功能：
vec_geofence <- function(left, bottom, right,top, lat, lon) {
# The mask vector represents whether a coordinate is seen in any of the
# fences defined by the top, left, bottom and right vectors. In the beginning
# all the coordinates haven't been tested, so the respective value in the
# mask vector is initialized as False.
mask <- rep(F, length(lon))
# For each fence...
for(i in seq_along(top)) {
# ... check for all the coordinates if they are inside of the fence
if( left[i] > right[i] )
new_mask <- top[i] >= lat & lat >= bottom[i] & (left[i] <= lon | lon <= right[i])
else
new_mask <- top[i] >= lat & lat >= bottom[i] & (left[i] <= lon & lon <= right[i])
# For all the coordinates that hadn't yet been seen in a fence, and that
# are inside the current fence, update the respective mask value to True
mask[!mask][new_mask] <- T
# The coordinates that will pass through to the next fence check are the ones
# that still haven't been seen inside a fence
lat <- lat[!new_mask]
lon <- lon[!new_mask]
}
mask
}
此函数生成一个真/假值的索引向量所以我可以过滤出哪些点不在给定的BBOX中。然而，有些地方是错误的。
它应该给我一个只有真值的向量因为所有的点实际上都在BBOX中。然而，它产生了以下结果：
[1] FALSE TRUE TRUE FALSE TRUE TRUE FALSE FALSE TRUE TRUE
这意味着根据函数，并非所有给定点都在BBOX内。
请帮我找出错误。非常感谢。
##############示例数据：
test_data<-structure(list(V1 = c("47.8924", "47.81252", "47.84976", "47.89307",
"47.8497", "47.8497", "47.89152", "47.88932",
"47.84252", "47.80853"),
V2 = c("11.7018", "12.07387", "12.08231", "11.69957",
"12.0824","12.08272", "11.69514", "11.70749",
"12.11194", "12.07071")),
row.names = c(NA,-10L), class = c("data.table", "data.frame"))
bbox_dimensions <- structure(c(xmin = 11.7154051652041, ymin = 47.7709252414407,
xmax = 12.3228827739125, ymax = 48.1788333505125),
class = "bbox", crs = structure(list(
input = "EPSG:4326", wkt = "GEOGCS["WGS 84",n
DATUM["WGS_1984",n SPHEROID["WGS 84",6378137,298.257223563,n
AUTHORITY["EPSG","7030"]],n AUTHORITY["EPSG","6326"]],n
PRIMEM["Greenwich",0,n AUTHORITY["EPSG","8901"]],n
UNIT["degree",0.0174532925199433,n
AUTHORITY["EPSG","9122"]],n
AUTHORITY["EPSG","4326"]]"), class = "crs"))
vec_geofence <- function(left, bottom, right,top, lat, lon) {
# The mask vector represents whether a coordinate is seen in any of the
# fences defined by the top, left, bottom and right vectors. In the beginning
# all the coordinates haven't been tested, so the respective value in the
# mask vector is initialized as False.
mask <- rep(F, length(lon))
# For each fence...
for(i in seq_along(top)) {
# ... check for all the coordinates if they are inside of the fence
if( left[i] > right[i] )
new_mask <- top[i] >= lat & lat >= bottom[i] & (left[i] <= lon | lon <= right[i])
else
new_mask <- top[i] >= lat & lat >= bottom[i] & (left[i] <= lon & lon <= right[i])
# For all the coordinates that hadn't yet been seen in a fence, and that
# are inside the current fence, update the respective mask value to True
mask[!mask][new_mask] <- T
# The coordinates that will pass through to the next fence check are the ones
# that still haven't been seen inside a fence
lat <- lat[!new_mask]
lon <- lon[!new_mask]
}
mask
}
test_data_index<-vec_geofence(bbox_dimensions[1],bbox_dimensions[2],bbox_dimensions[3],bbox_dimensions[4],
as.numeric(test_data$V1), as.numeric(test_data$V2))
它指出我的数据不正确。该算法按预期工作。谢谢你指出这一点。