soil.spec (version 2.1.4)

SpectraPoints-class: A class for spectral absorbance measurements

Description

A class for spectral absorbance measurements typically in the medium infra-red range (MIR), visible near infra-red (VISMIR) and near-infra-red.

Slots

metadata:

object of class "data.frame"; metadata table containg relevant information such as "MID" (metadata ID), "Instrument_name", "Instrument_URL", "Laboratory_name", "Laboratory_contact" (contact person and his/her e-mail address), "Laboratory_URL", "Material_class" (e.g. soil or vegetation), "Wavenumber_conversion", "Wavenlength_unit", "Location_error"

data:

object of class "Spectra"; contains absorbance values in wide or long format

sp:

object of class "SpatialPoints"; sampling locations

Methods

summary

signature(obj = "SpectraPoints"): default summary of the object showing number of bands and points

validate

signature(obj = "SpectraPoints"): check for overlap in feature space in comparison to the calibration data

Details

The class expects by default absorbance, and not reflectance values. For large data sets we advise using the wide data format.

See Also

fit.SpectraModel

Examples

## generate the class:
library(sp)
library(rgdal)

data(afspec)
## get spatial coordinates:
sp <- afspec$samples[,c("Longitude","Latitude")]
coordinates(sp) <- ~Longitude+Latitude
proj4string(sp) <- CRS("+proj=longlat +datum=WGS84")
## prepare 'samples' table
samples <- cbind(afspec$samples["SAMPLEID"], 
    MID="AfSIS-MIR", 
    DateTime=Sys.time())
## convert to "SpectraPoints"
afspec.sp <- SpectraPoints(Spectra=Spectra(samples, afspec$ab), sp=sp)
summary(afspec.sp)
plot(afspec.sp@data)
data(m.PHIHOX)