R 从TXT到空间数据：lat/long格式问题

我试图从R中导入的txt文件创建一个空间数据集，其结构如下：

CitiesTXTSel=

     COM   City_NAME     LONGI_DMS  LATI_DMS
     445   VILLEMOTIER   51916      462046
      98   CHAZEY-BONS   54054      454811
      57   BOZ           45434      462425

当我使用下面的函数时，会收到以下错误消息： “CheckNumericImpresse2Double（obj）中出错：非有限坐标”

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我猜Cooridate的预格式化是不正确的，但我不知道如何解决这个问题。请问你能帮忙吗？导入的坐标以Lat/long DMS表示。

我不知道R，但标题中的DMS可能代表度-分-秒-您可能需要将它们转换为十进制度？嗨，Jon，这确实是一个解决方案。我在txt文件中有另一个地理参考系统的坐标。我试着用这个来代替。

# Reproducing your data frame
CitiesTXTSel <- data.frame(
  COM = c(445, 98, 7),
  City_NAME = c("VILLEMOTIER", "CHAZEY-BONS", "BOZ"),
  LONGI_DMS = c(51916, 54054, 45434),
  LATI_DMS = c(462046, 454811, 462425),
  stringsAsFactors = FALSE
)

# a function to convert your input to decimal degrees
convert_DMS_dec <- function(DMS) {
  DMS_pad <- sprintf("%7s", DMS)
  deg <- substr(DMS_pad, 1, 3)
  deg <- gsub(" ", "", deg) # remove leading whitespace
  min <- substr(DMS_pad, 4, 5)
  sec <- substr(DMS_pad, 6, 7)
  DMS_split <- paste(deg, min, sec)
  dec_deg <- conv_unit(DMS_split, "deg_min_sec", "dec_deg")
  round(as.numeric(dec_deg), 4) # precision to about one arc-second
}

CitiesTXTSel$long <- convert_DMS_dec(CitiesTXTSel$LONGI_DMS)
CitiesTXTSel$lat <- convert_DMS_dec(CitiesTXTSel$LATI_DMS)

# re-order the data frame so columns three and four match your code
CitiesTXTSel <- CitiesTXTSel[, c(1:2, 5:6, 3:4)]

# Your code, indented a little for clarity
Cities= SpatialPointsDataFrame(
  coords=CitiesTXTSel[,3:4], 
  data=CitiesTXTSel[,1:2], 
  proj4string=CRS("+proj=longlat +datum=wgs84")
)

# Reproducing your data frame
CitiesTXTSel <- data.frame(
  COM = c(445, 98, 7),
  City_NAME = c("VILLEMOTIER", "CHAZEY-BONS", "BOZ"),
  LONGI_DMS = c(51916, 54054, 45434),
  LATI_DMS = c(462046, 454811, 462425),
  stringsAsFactors = FALSE
)

# a function to convert your input to decimal degrees
convert_DMS_dec <- function(DMS) {
  DMS_pad <- sprintf("%7s", DMS)
  deg <- substr(DMS_pad, 1, 3)
  deg <- gsub(" ", "", deg) # remove leading whitespace
  min <- substr(DMS_pad, 4, 5)
  sec <- substr(DMS_pad, 6, 7)
  DMS_split <- paste(deg, min, sec)
  dec_deg <- conv_unit(DMS_split, "deg_min_sec", "dec_deg")
  round(as.numeric(dec_deg), 4) # precision to about one arc-second
}

CitiesTXTSel$long <- convert_DMS_dec(CitiesTXTSel$LONGI_DMS)
CitiesTXTSel$lat <- convert_DMS_dec(CitiesTXTSel$LATI_DMS)

# re-order the data frame so columns three and four match your code
CitiesTXTSel <- CitiesTXTSel[, c(1:2, 5:6, 3:4)]

# Your code, indented a little for clarity
Cities= SpatialPointsDataFrame(
  coords=CitiesTXTSel[,3:4], 
  data=CitiesTXTSel[,1:2], 
  proj4string=CRS("+proj=longlat +datum=wgs84")
)

        coordinates COM   City_NAME
 (5.3211, 46.3461) 445 VILLEMOTIER
 (5.6817, 45.8031)  98 CHAZEY-BONS
 (4.9094, 46.4069)   7         BOZ