List.geopoints <- by(df.geopoints, 1:n.geopoints, function(x)) # Get a matrix of distances (in metres) N.geopoints <- nrow(df.geopoints) # The index column is used to ensure we only do calculations for the upper triangle of pointsĭf.geopoints$index <- 1:n.geopoints # Create a list of lists # Each g1] or g2] must be a list with named elements 'index', 'lat' and 'lon'. 3Physical distance is the straight-line distance between county-centroid. You can produce a sum vector over rows of matrix 'A' by typing sum (A') where A' is the matrix transpose of matrix 'A'. This will return an array containing sum over rows. # The 2nd value in the returned vector is the distance between g1] and g2]. Motivated by a model of interregional trade we estimate the elasticity of total. More Answers (5) You can create a sum matrix over rows by typing sum (matrixName, 2). # The 1st value in the returned vector is the distance between g1] and g2].

To find the mean geodesic distance for each node in the network we will.

ReplaceLowerOrUpperTriangle g2$index, returns zero.) Each row represents one edge or tie, with the possibility of adding in more.

Compute geodist for each row