search for: drainage_area

Dear R-users, I've spent most of the day reading R documentation at length but couldn't find something perhaps obvious. I have a dataset made of 3 morphometric variables for a series of watershed [log(slope); log(drainage_area); distance_to_outlet] My aim is to predict the value of log(slope) for pairs of [drainage_area; distance_to_outlet] (sounds like a plain linear model fitting, right, nothing too fancy there). In the literature, the standard procedure is to reduce the number of observations by computing the mean va...

Dear R users, I am sorry to ask you such a pathetic newbie question, but how does one append data at the end of a data frame? I am working with GRASS/R library, but the question is about R. I have a data.frame containing the following variables basinID, distoutlet, drainage_area, slope These variables are stored for all pixels of Grass Raster objects. For each drainage basin (basinID), I'd like to find the maximum of distoutlet. How can I store the pair of info (bv$ID, max(bv$distoutlet)) at each step of the for loop ? I presume something like this could do for (i 1...