diff --git a/core/client/components/chart/KDataTable.vue b/core/client/components/chart/KDataTable.vue
index c4ce664e8..4af32d39e 100644
--- a/core/client/components/chart/KDataTable.vue
+++ b/core/client/components/chart/KDataTable.vue
@@ -30,7 +30,7 @@ import _ from 'lodash'
 import moment from 'moment'
 import Papa from 'papaparse'
 import { ref, watch } from 'vue'
-import { downloadAsBlob, convertTimeSerie } from '../../utils'
+import { downloadAsBlob } from '../../utils'
 import { useSchema } from '../../composables'
 import { Units } from '../../units.js'
 import { Time } from '../../time.js'
@@ -71,7 +71,6 @@ const height = ref(0)
 // Used to store template compilers per field
 const compilers = {}
 const exportCompilers = {}
-let propertiesToConvert = []
 
 // Watch
 watch(() => props.tables, update)
@@ -82,14 +81,11 @@ async function update () {
   await compile(props.schema)
   columns.value = []
   const invisibleColumns = []
-  propertiesToConvert = []
   _.forOwn(schema.value.properties, (value, key) => {
     const type = _.get(value, 'type')
     // FIXME: allow for custom representation of complex objects
     if (type === 'object') return
     const label = _.get(value, 'field.label', _.get(value, 'field.helper', key))
-    const convertToDefaultUnit = _.get(value, 'field.defaultUnit', false)
-    if (convertToDefaultUnit) propertiesToConvert.push(key)
     const visible = _.get(value, 'field.visible', true)
     if (!visible) invisibleColumns.push(key)
     const formatter = _.has(value, 'field.formatter') ? _.get(props.formatters, value.field.formatter) : null
@@ -135,7 +131,6 @@ async function update () {
   rows.value = []
   for (const table of props.tables) {
     const data = await table.data
-    convertTimeSerie(data, table.variable, propertiesToConvert)
     rows.value = rows.value.concat(data)
   }
 }
@@ -148,7 +143,6 @@ async function exportData (options = {}) {
   for (let i = 0; i < props.tables.length; i++) {
     const table = props.tables[i]
     const data = await table.data
-    await convertTimeSerie(data, table.variable, propertiesToConvert)
     for (const item of data) {
       const row = {}
       _.forOwn(schema.value.properties, (value, key) => {
diff --git a/core/client/components/chart/KTimeSeriesChart.vue b/core/client/components/chart/KTimeSeriesChart.vue
index f4c2dce1e..fc6f6ac13 100644
--- a/core/client/components/chart/KTimeSeriesChart.vue
+++ b/core/client/components/chart/KTimeSeriesChart.vue
@@ -81,9 +81,6 @@ function getUnit (timeSerie) {
 function getTargetUnit (timeSerie) {
   return _.get(timeSerie, 'variable.targetUnit')
 }
-function setUnit (timeserie, targetUnit) {
-  _.set(timeserie, 'variable.unit', targetUnit)
-}
 function getZoom () {
   const start = moment.utc(_.get(chart, 'scales.x.min'))
   const end = moment.utc(_.get(chart, 'scales.x.max'))
@@ -246,8 +243,8 @@ function makeScales (datasets) {
   let axisId = 0
   for (const timeSerie of props.timeSeries) {
     const unit = getUnit(timeSerie)
-    const targetUnit = getTargetUnit(timeSerie) || unit
-    const unitName = targetUnit.name
+    const targetUnit = getTargetUnit(timeSerie)
+    const unitName = (targetUnit ? targetUnit.name : unit.name)
     if (!unit2axis.has(unitName)) {
       // Ensure a related dataset does exist
       const axisDatasets = _.filter(datasets, dataset => (_.get(dataset, 'targetUnit.name', _.get(dataset, 'unit.name')) === unitName))
@@ -257,12 +254,11 @@ function makeScales (datasets) {
       axisDatasets.forEach(dataset => Object.assign(dataset, { yAxisID: axis }))
       unit2axis.set(unitName, axis)
       scales[axis] = _.merge({
-        targetUnit: unitName,
         type: props.logarithmic ? 'logarithmic' : 'linear',
         position: (axisId + 1) % 2 ? 'left' : 'right',
         title: {
           display: true,
-          text: i18n.tie(targetUnit.symbol)
+          text: i18n.tie(targetUnit ? targetUnit.symbol : unit.symbol)
         },
         ticks: {
           callback: function (value, index, values) {
@@ -288,7 +284,6 @@ async function makeDatasets () {
     const label = _.get(timeSerie, 'variable.label')
     const unit = getUnit(timeSerie)
     const targetUnit = getTargetUnit(timeSerie)
-    if (targetUnit) setUnit(timeSerie, targetUnit)
     const data = await timeSerie.data
     // No data ?
     if (_.isEmpty(data)) continue
@@ -308,10 +303,6 @@ async function makeDatasets () {
       if (_.has(item, yAxisKey)) {
         let value = _.get(item, yAxisKey)
         if (_.isFinite(value)) {
-          if (targetUnit) {
-            value = Units.convert(value, unit.name, targetUnit.name)
-            _.set(item, yAxisKey, value)
-          }
           if (_.isNil(min[unitName]) || (value < min[unitName])) min[unitName] = value
           if (_.isNil(max[unitName]) || (value > max[unitName])) max[unitName] = value
         }
diff --git a/core/client/units.js b/core/client/units.js
index b5c445f4c..85b2636a8 100644
--- a/core/client/units.js
+++ b/core/client/units.js
@@ -286,15 +286,25 @@ export const Units = {
   },
   // Get unit definition by name
   getUnit (unit) {
-    return _.find(this.getUnits(), { name: unit })
+    // Not optimized
+    //return _.find(this.getUnits(), { name: unit })
+    let definition
+    _.forOwn(this.get(), (units, quantity) => {
+      // Already found ?
+      if (definition) return
+      else if (_.has(units, unit)) definition = Object.assign({ name: unit, quantity }, _.get(units, unit))
+    })
+    return definition
   },
-  // Get unit symbol by unit name
+  // Get unit symbol by unit name/definition
   getUnitSymbol (unit) {
-    const definition = this.getUnit(unit)
+    const definition = (typeof unit === 'object' ? unit : this.getUnit(unit))
     return (definition ? i18n.tie(definition.symbol) : unit)
   },
-  // Get default unit definition (if any) for a given quantity/unit name
+  // Get default unit definition (if any) for a given quantity/unit name/definition
   getDefaultUnit (quantityOrUnit) {
+    if (!quantityOrUnit) return null
+    if (typeof quantityOrUnit === 'object') quantityOrUnit = quantityOrUnit.name
     // Check for quantity first
     let defaultUnit = Store.get(`units.default.${quantityOrUnit}`)
     // If not check by matching quantity based on given unit
@@ -302,44 +312,50 @@ export const Units = {
       const baseUnit = this.getUnit(quantityOrUnit)
       // Get default unit for this quantity instead
       if (baseUnit) defaultUnit = this.getDefaultUnit(baseUnit.quantity)
+    } else {
+      // Jump from name to definition
+      defaultUnit = this.getUnit(defaultUnit)
     }
     return defaultUnit
   },
+  // Set default unit name for a quantity
   setDefaultUnit (quantity, unit) {
     Store.set(`units.default.${quantity}`, unit)
   },
-  // Get symbol of default unit (if any) for a given quantity/unit name
+  // Get symbol of default unit (if any) for a given quantity/unit name/definition
   getDefaultUnitSymbol (quantityOrUnit) {
     return this.getUnitSymbol(this.getDefaultUnit(quantityOrUnit))
   },
-  // Get target unit for a source unit, will be default unit (if any) or source unit
+  // Get target unit definition for a source unit name/definition, will be default unit (if any) or source unit
   getTargetUnit (sourceUnit) {
-    return this.getDefaultUnit(sourceUnit) || sourceUnit
+    return this.getDefaultUnit(sourceUnit) || (typeof sourceUnit === 'object' ? sourceUnit : this.getUnit(sourceUnit))
   },
-  // Get target unit symbol for a source unit, will be default unit symbol (if any) or source unit symbol
+  // Get target unit symbol for a source unit name/definition, will be default unit symbol (if any) or source unit symbol
   getTargetUnitSymbol (sourceUnit) {
     return this.getUnitSymbol(this.getTargetUnit(sourceUnit))
   },
-  // Convert between units by names
+  // Convert between units by names/definitions
   // If target unit is not specified will use default unit (if any) for source unit
   convert (value, sourceUnit, targetUnit) {
-    if (_.isNil(value)) {
-      logger.warn('[KDK] cannont convert a nil value')
-      return
-    }
+    if (_.isNil(value) || !_.isFinite(value)) return value
     if (value === Number.MIN_VALUE || value === Number.MAX_VALUE) return value
-    // If target unit is same as source unit does nothing
-    if (targetUnit === sourceUnit) return value
+    if (typeof sourceUnit === 'string') sourceUnit = this.getUnit(sourceUnit)
+    if (typeof targetUnit === 'string') targetUnit = this.getUnit(targetUnit)
     // If target unit is not given use default one
     if (!targetUnit) targetUnit = this.getDefaultUnit(sourceUnit)
-    // Check if the target unit does exist
-    if (!targetUnit) return value
-    // Check if the source unit does exist
-    if (!math.Unit.isValuelessUnit(sourceUnit)) return value
-    let n = math.unit(value, sourceUnit)
-    n = n.toNumber(targetUnit)
+    // Check if the source/target unit does exist
+    if (!sourceUnit || !targetUnit) return value
+    // If target unit is same as source unit does nothing
+    if (sourceUnit && targetUnit && (targetUnit.name === sourceUnit.name)) return value
+    // Check if the source unit is declared in the units system
+    if (!math.Unit.isValuelessUnit(sourceUnit.name)) return value
+    // Check if the value is a valid number
+    if (!_.isFinite(value)) return value
+    // Now convert
+    let n = math.unit(value, sourceUnit.name)
+    n = n.toNumber(targetUnit.name)
     // Remap from [-180,+180[ to [0,360[ for angles
-    n = (targetUnit === 'deg' ? (n < 0.0 ? n + 360.0 : n) : n)
+    n = (targetUnit.name === 'deg' ? (n < 0.0 ? n + 360.0 : n) : n)
     return n
   },
   // Format display of source value in target unit, converting from source unit
diff --git a/core/client/utils/index.js b/core/client/utils/index.js
index ddaabc623..bd5429413 100644
--- a/core/client/utils/index.js
+++ b/core/client/utils/index.js
@@ -8,7 +8,6 @@ export * from './utils.account.js'
 export * from './utils.actions.js'
 export * from './utils.colors.js'
 export * from './utils.content.js'
-export * from './utils.data.js'
 export * from './utils.locale.js'
 export * from './utils.math.js'
 export * from './utils.platform.js'
diff --git a/core/client/utils/utils.data.js b/core/client/utils/utils.data.js
deleted file mode 100644
index 31b402a26..000000000
--- a/core/client/utils/utils.data.js
+++ /dev/null
@@ -1,22 +0,0 @@
-import _ from 'lodash'
-import { Units } from '../units.js'
-
-export function convertData (data, valuePaths, sourceUnit, targetUnit) {
-  if (!Array.isArray(valuePaths)) valuePaths = [valuePaths]
-  _.forEach(data, document => {
-    _.forEach(valuePaths, valuePath => {
-      const value = _.get(document, valuePath)
-      if (value) _.set(document, valuePath, Units.convert(value, sourceUnit.name, targetUnit.name))
-    })
-  })
-}
-
-export function convertTimeSerie (data, variable, valuePaths) {
-  if (!Array.isArray(valuePaths)) valuePaths = [valuePaths]
-  const unit = variable.unit
-  const targetUnit = variable.targetUnit || Units.getDefaultUnit(unit.name)
-  if (unit.name !== targetUnit.name) {
-    convertData(data, valuePaths, unit, targetUnit)
-    variable.unit = targetUnit
-  }
-}
\ No newline at end of file
diff --git a/map/client/utils/utils.time-series.js b/map/client/utils/utils.time-series.js
index 53ac1084a..505c99b38 100644
--- a/map/client/utils/utils.time-series.js
+++ b/map/client/utils/utils.time-series.js
@@ -16,7 +16,10 @@ async function getDataForVariable(data, variable, forecastLevel, runTime) {
   // Aggregated variable available for feature ?
   if (properties[name] && Array.isArray(properties[name])) {
     // Build data structure as expected by visualisation
-    values = properties[name].map((value, index) => ({ time: moment.utc(times[name][index]).valueOf(), [name]: value }))
+    values = properties[name].map((value, index) => {
+      value = Units.convert(value, variable.unit, variable.targetUnit)
+      return { time: moment.utc(times[name][index]).valueOf(), [name]: value }
+    })
     // Keep only selected value if multiple are provided for the same time (eg different forecasts)
     if (variable.runTimes && runTime && !_.isEmpty(_.get(runTimes, name))) {
       values = values.filter((value, index) => (runTimes[name][index] === runTime.toISOString()))
@@ -86,6 +89,7 @@ export function getTimeSeries({
     const baseUnit = _.get(properties, 'unit', variable.unit)
     // Known by the unit system ?
     const unit = Units.getUnit(baseUnit) || { name: baseUnit }
+    const targetUnit = Units.getTargetUnit(baseUnit)
     const serie = {
       probedLocation: data,
       data: getDataForVariable(data, variable, forecastLevel),
@@ -93,7 +97,7 @@ export function getTimeSeries({
         name: variable.name,
         label: `${i18n.tie(variable.label)} (${Units.getTargetUnitSymbol(baseUnit)})`,
         unit,
-        targetUnit: Units.getTargetUnit(unit),
+        targetUnit,
         chartjs: Object.assign({
           parsing: {
             xAxisKey: 'time',