help with grouping data and calculating the means

Hi Sasa,

Those latitude look equidistant with a separation of 0.05.
I guess you want to calculate the zonal mean along the latitude, right?

#estimate the lower and upper latitude for the cut
lat.dist=0.05 #equidistant spacing along latitude
lat.min=min(df$LAT,na.rm=T)-lat.dist/2
lat.max=max(df$LAT,na.rm=T)+lat.dist/2
cat.lat=cut(df$LAT,breaks=seq(lat.min,lat.max,by=lat.dist));cat.lat

#just show which indices are grouped
tapply(df$TK.QUADRANT,cat.lat, paste,collapse=",")

#calculate the mean of whatever column. The lat.mean will have NA for any latitude cell where the df column has no data
lat.mean=tapply(df$TK.QUADRANT,cat.lat, mean)

#if you need to remove any potential NAs
lat.mean[!is.na(lat.mean)]

cheers/beste Gr??e
Peter

`TK-QUADRANT` <- c(9161,9162,9163,9164,10152,10154,10161,10163)
LAT <- c(55.07496,55.07496,55.02495,55.02496
,54.97496,54.92495,54.97496,54.92496)
LON <-
c(8.37477,8.458109,8.37477,8.45811,8.291435,8.291437,8.374774,8.374774)
df <- data.frame(`TK-QUADRANT`=`TK-QUADRANT`,LAT=LAT,LON=LON)