inst/doc/working-with-units.R

In clnsmth/EML103: Read and Write Ecological Metadata Language Files

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library("EML")

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f <- system.file("xsd/test/eml-datasetWithUnits.xml", package = "EML")
eml <- read_eml(f)

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attribute_tables <- eml_get(eml, "attributeList")


a <- attribute_tables$attributes
numerics <- a[a$domain == "numericDomain",]
numerics

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units <- numerics$unit
units[ !is_standardUnit(units) ]

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standardUnits <- get_unitList()
standardUnits$units

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customUnits <- get_unitList(eml@additionalMetadata[[1]]@metadata)
customUnits

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which(standardUnits$unitTypes$id == "arealDensity")
standardUnits$unitTypes[c(55,56),]

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i <- which(standardUnits$units$abbr == "btu")
j <- which(standardUnits$units$abbr == "μm³/kg")
standardUnits$units[c(i,j),]

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df <- data.frame(attributeName = "energy", 
                   attributeDefinition = "energy absorbed by the surface", 
                   unit = "britishThermalUnit", 
                   numberType = "real",
                   stringsAsFactors = FALSE)
  attributeList <- set_attributes(df, col_classes = "numeric")

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custom_units <- data.frame(id = "speciesPerSquareMeter", unitType = "arealDensity", parentSI = "numberPerSquareMeter", multiplierToSI = 1, description = "number of species per square meter")
set_unitList(custom_units)

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unique(standardUnits$unitTypes$id)

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unitType <- data.frame(id = c("jerk", "jerk"), dimension = c("length", "time"), power = c(1, -3) )

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unit <- data.frame(id = "meterPerSecondCubed", unitType = "jerk")

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unitList <- set_unitList(unit, unitType)

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eml <- new("eml", additionalMetadata = as(unitList, "additionalMetadata"))

## ----eval=FALSE----------------------------------------------------------
#  library("udunits2")