# snapPointsToLines

From maptools v0.8-37
by Roger Bivand

##### Snap a set of points to a set of lines

This function snaps a set of points to a set of lines based on the minimum distance of each point to any of the lines. This function does not work with geographic coordinates.

- Keywords
- spatial

##### Usage

`snapPointsToLines(points, lines, maxDist = NA, withAttrs = TRUE, idField=NA)`

##### Arguments

- points
- An object of the class SpatialPoints or SpatialPointsDataFrame.
- lines
- An object of the class SpatialLines or SpatialLinesDataFrame.
- maxDist
- Numeric value for establishing a maximum distance to avoid snapping points that are farther apart. This parameter is optional.
- withAttrs
- Boolean value for preserving (TRUE) or getting rid (FALSE) of the original point attributes. Default: TRUE. This parameter is optional.
- idField
- A string specifying the field which contains each line's id. This id will be transferred to the snapped points data set to distinguish the line which each point was snapped to.

##### Value

- SpatialPointsDataFrame object as defined by the R package 'sp'. This object contains the snapped points, therefore all of them lie on the lines.

##### See Also

##### Examples

```
# From the sp vignette
l1 = cbind(c(1,2,3),c(3,2,2))
l1a = cbind(l1[,1]+.05,l1[,2]+.05)
l2 = cbind(c(1,2,3),c(1,1.5,1))
Sl1 = Line(l1)
Sl1a = Line(l1a)
Sl2 = Line(l2)
S1 = Lines(list(Sl1, Sl1a), ID="a")
S2 = Lines(list(Sl2), ID="b")
Sl = SpatialLines(list(S1,S2))
df = data.frame(z = c(1,2), row.names=sapply(slot(Sl, "lines"), function(x) slot(x, "ID")))
Sldf = SpatialLinesDataFrame(Sl, data = df)
xc = c(1.2,1.5,2.5)
yc = c(1.5,2.2,1.6)
Spoints = SpatialPoints(cbind(xc, yc))
if (rgeosStatus()) snapPointsToLines(Spoints, Sldf)
```

*Documentation reproduced from package maptools, version 0.8-37, License: GPL (>= 2)*

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