# dist2line: Distance between points and lines or the border of polygons. In geosphere: Spherical Trigonometry

## Description

The shortest distance between points and polylines or polygons.

## Usage

 `1` ```dist2Line(p, line, distfun=distGeo) ```

## Arguments

 `p` longitude/latitude of point(s). Can be a vector of two numbers, a matrix of 2 columns (first one is longitude, second is latitude) or a SpatialPoints* object `line` longitude/latitude of line as a matrix of 2 columns (first one is longitude, second is latitude) or a SpatialLines* or SpatialPolygons* object `distfun` A distance function, such as distGeo

## Value

matrix with distance and lon/lat of the nearest point on the line. Distance is in the same unit as `r` in the `distfun`(default is meters). If `line` is a `Spatial*` object, the ID (index) of (one of) the nearest objects is also returned. Thus if the objects are polygons and the point is inside a polygon the function may return the ID of a neighboring polygon that shares the nearest border. You can use the `over` functions in packages `sp` or `rgeos` for point-in-polygon queries.

## Author(s)

George Wang and Robert Hijmans

`dist2gc, alongTrackDistance `

## Examples

 ```1 2 3 4 5 6 7 8 9``` ```line <- rbind(c(-180,-20), c(-150,-10), c(-140,55), c(10, 0), c(-140,-60)) pnts <- rbind(c(-170,0), c(-75,0), c(-70,-10), c(-80,20), c(-100,-50), c(-100,-60), c(-100,-40), c(-100,-20), c(-100,-10), c(-100,0)) d = dist2Line(pnts, line) plot( makeLine(line), type='l') points(line) points(pnts, col='blue', pch=20) points(d[,2], d[,3], col='red', pch='x') for (i in 1:nrow(d)) lines(gcIntermediate(pnts[i,], d[i,2:3], 10), lwd=2) ```

### Example output

```Loading required package: sp
```

geosphere documentation built on Nov. 17, 2017, 4:59 a.m.