points2network function

Integrate a point data set into a network

A function to integrate an individual point data set into a network under different rules (see details below).

points2network(ntdata,pointsxy,approach=1,ELComputed=FALSE,longlat=F,
               Detailed=F, ea.prop=NULL)

Arguments

• ntdata: A SpatialLinesDataFrame or SpatialLines object

• pointsxy: A two-column matrix of point coordinates (X, Y)

• approach: specified by an integer ranging from 1 to 4 to define the approach for integration:

  1: Mapping each point to the nearest node in the network/graph

  2: Mapping each point to the nearest point (add them as nodes if they are not) on the network

  3: Add a new edge(virtual edge) between each point and the nearest node

  4: Add a new edge(virtual edge) between each point and the nearest point

• ELComputed: If TRUE, the length of each edge will be calculated and returned

• longlat: If TRUE, distances on an ellipse with WGS84 parameters will be returned

• Detailed: If TRUE, all the vertices within the polylines of a spatial network will be recognised as nodes; if FALSE, only two endpoints of each polyline are treated as nodes

• ea.prop: A vector (of the length equalling to the number of edge attributes in in the network ntdata ) with values of 1 or 0:

  1: the corresponding column in the data frame will be kept for the new network;

  0: the corresponding column in the data frame will not be kept.

Returns

A list consisted of: - nodelist: A nodelist object

• edgelist: An edgelist object

• CoorespondIDs: A vector of the cooresponding node ID for each point in pointsxy

• nodexlist: A vector contains X-coordinates of all the nodes

• nodeylist: A vector contains Y-coordinates of all the nodes

• Eadf: A data frame of attributes of the returned edges, of which the structure is a data frame with [EdgeID,(attributes inherited from the input network data)]

• VElist: A list of virtual edges if added, i.e. approaches 3 and 4 are used

• Edgelength: If ELComputed is TRUE, lengths of all the edges will be returned as a numeric vector; otherwise it will be NULL.

See Also

ptsinnt.view

Examples

## Not run:

data(ORN)
pts<-spsample(ORN.nt, 100, type="random")
ptsxy<-coordinates(pts)[,1:2]
ptsxy<-cbind(ptsxy[,1]+0.008,ptsxy[,2]+0.008)
#Mapping each point to the nearest node in the network/graph
res<-points2network(ntdata=ORN.nt,pointsxy=ptsxy, approach=1)
ptsinnt.view(ntdata=rn, nodelist=res[[1]], pointsxy=ptsxy,
             CoorespondIDs=res[[3]])
#Mapping each point to the nearest point (add them as nodes if they are not) on 
#the network
res<-points2network(ntdata=ORN.nt,pointsxy=ptsxy, approach=2,ea.prop=rep(0,37))
ptsinnt.view(ntdata=ORN.nt, nodelist=res[[1]], pointsxy=ptsxy, CoorespondIDs=res[[3]]) 
#Add a new edge(Virtual edge) between each point and the nearest node
res<-points2network(ntdata=ORN.nt,pointsxy=ptsxy, approach=3,ea.prop=rep(0,37))
VElist<-res[[7]]
ptsinnt.view(ntdata=ORN.nt, nodelist=res[[1]], pointsxy=ptsxy, CoorespondIDs=res[[3]], 
             VElist=VElist)
#Add a new edge(Virtual edge) between each point and the nearest point
res<-points2network(ntdata=ORN.nt,pointsxy=ptsxy, approach=4,ea.prop=rep(0,37))
VElist<-res[[7]]
ptsinnt.view(ntdata=ORN.nt, nodelist=res[[1]], pointsxy=ptsxy, CoorespondIDs=res[[3]],
             VElist=VElist) 
## End(Not run)

Author(s)

Binbin Lu binbinlu@whu.edu.cn