# Resampling 0.7 m LiDAR (in raster already) to 10 m DEM in R?

How do I resample the 0.7 m LiDAR to 10 m DEM in R?

What are the basic rules for checking the consistency?

One way to do is using `resample` from `raster` package. Two methods are available: 'bilinear' and 'nearest neighbour' (pick nearest neighbour, as suggested in Resample binary raster to give *proportion* within new cell window).

See the example code from `raster` package documentation:

``````# this is a sample code which you need to adapt to your specific case.
r <- raster(nrow=3, ncol=3)
r[] <- 1:ncell(r)
s <- raster(nrow=10, ncol=10)
s <- resample(r, s, method='bilinear')
#par(mfrow=c(1,2))
``````

In the example above, `r` is your 0.7 m LiDAR DEM, and `s` is the raster object to be resampled. Make sure `s` has the following parameters equal to `r`:

• origin (see `xmn`, `ymn` parameters). OR
• `ext` (extent, aka bounding box). If you want `r` and `s` to have the same extent (i.e., to match in their outside borders), you need to resample to a cell size multiple from 0.7 m. For example, 9.8 m. AND
• `crs` (Coordinate Reference System).

Check the `raster` function to know how to set above parameters in `s`.

• The question is about aggregation, not about interpolation. – Mike T Jan 22 at 1:05
• @MikeT, the question is about resampling, which is a method of interpolation (one interpolates within the new cell, from the previous multiple cells; but aggregation is correct as well). – Andre Silva Jan 22 at 1:08
• A bilinear method is good for interpolation (i.e. constructing new data points within the range of a discrete set of known data points). However, bilinear is a poor choice when aggregating to a coarser resolution. See more details here and here. – Mike T Jan 22 at 1:20
• `raster::aggregate` looks like a promising approach (which I haven't used). However, it requires an integer factor, whereas 0.7 is not a factor of 10... – Mike T Jan 22 at 1:44