elevcheck: Elevation check
In biogeo: Point Data Quality Assessment and Coordinate Conversion

Description Usage Arguments Value Author(s) See Also Examples

Compares the recorded elevation values for records with values extracted from a digital elevation model and determines whether there is a mismatch in values.

1	elevcheck(dat, dem, elevc = "elevation", diff = 50)

`dat`	A dataframe containing the required fields, including: ID, x, y, Species, x_original, y_original, Correction, Modified, Reason and Exclude. Required fields that are missing can be added using addmainfields.
`dem`	A digital elevation model as a raster object.
`elevc`	The field containing the recorded elevation (or depth) values in meters.
`diff`	A threshold value for determining a mismatch between the recorded elevation and the elevation extracted from the digital elevation model. If values exceed this value then they are flagged as being mismatches.

A dataframe of two fields. Mismathes are indicated as ones in elevMismatch and the elevation values extracted from the digital elevation model are in demElevation.

Mark Robertson

errorcheck, quickclean

## Not run: 
gb <- keepmainfields(gbifdat,ID='',Species='species',x='decimallongitude',y='decimallatitude',
others=c('gbifid','elevation')) # Convert example data to biogeo format
gb <- gb[ gb$Species=='Heterotheca villosa', ] # Keep data for only one species
dem<-raster(dem,xmn=-180, xmx=180, ymn=-60, ymx=90)
gba<-elevcheck(gb,dem,elevc="elevation",diff=50)

## End(Not run)