search for: blackcel

Hi lily, It's not too hard to do it using dataframes. Getting the indexing right is usually that hardest part: # these values are the centers of the black cells lat<-rep(28:38,11) lon<-rep(98:108,each=11) pop<-sample(80:200,121) # just use the data.frame function blackcells<-data.frame(lat=lat,lon=lon,pop=pop) plot(0,type="n",xlim=c(97.5,108.5),ylim=c(27.5,38.5), xlab="Longitude",ylab="Latitude") abline(h=27.5) abline(h=lat+0.5) abline(v=97.5) abline(v=lon+0.5) text(blackcells$lon,blackcells$lat,pop) # the red cells will be centered...

...t; cells fall at the corners of four "black" cells. You can get the four "black" cells by finding the lat/lon values that are closest to the "red" lat/lon values. Here's a basic example: lat<-rep(28:38,11) lon<-rep(98:108,each=11) pop<-sample(80:200,121) blackcells<-list() for(i in 1:121) blackcells[[i]]<-list(lat=lat[i],lon=lon[i],pop=pop[i]) redcell<-list(lat=33.5,lon=100.5,pop=NA) close4<-rep(NA,4) closen<-1 for(i in 1:121) { if(abs(blackcells[[i]]$lat-redcell$lat) < 1 && abs(blackcells[[i]]$lon-redcell$lon) < 1) { close...

Hi Jim, Thanks. It works. I now have more complex problems. If at each blackcell, there are two variables such as pop and mood. For each variable, there are daily records in one year, so 365 records for pop and 365 records for mood. The averaged values for the redcells should be daily records too. What kind of format do you recommend for this problem? Right now, I just get the...

Hi R users, I have a question about data processing. I have such a dataset, while each black grid cell has a few attributes and the corresponding attribute values. The latitude and longitude of the center of each grid cell are given also. Then I want to average the attribute values from four adjacent grid cells to get the average value for the center of each red grid cell. Thus, there are the

Hi lily, You could also create "blackcells" as a dataframe (which is itself a type of list). I used a list as I thought it would be a more general solution if there were different numbers of values for different grid cells. The use of 1 for the comparison was due to the grid increments being 1. If you had larger or smaller grid incre...