The use of metric and standard units of measurement is not always consistent so it can be useful to display both (meters and feet for example) on a map.  Surfer's colorscale does not support the display of two label sets but it is possible to use a script to achieve this result.  The script below will add a second set of labels to a colorscale with different units.  It is currently written to convert meters to feet so some adjustments are needed if your units are different.

To run this script:

1. Copy the script below, or download the attached BAS file: ContourMap_DualUnitColorscale.BAS.
2. In a Windows Explorer window, navigate to C:\Program Files\Golden Software\Surfer.
3. Double click on Scripter.exe to launch Scripter.
4. Press Ctrl+A to select all of the existing lines then press Delete.
5. If you copied this script, press Ctrl+V to paste it into Scripter. If you downloaded it, click File | Open, select the BAS file from your downloads directory, and click Open.
6. In the Variables section, update the custom parameters to match your map:
   1. MtoF = the conversion factor to convert from your current to your desired units
   2. zMinM = the minimum contour of the map
   3. zMaxM = the maximum contour of the map
   4. zIntM = the contour interval of the map
6. Click Script | Run to run the script.

Sub Main
Debug.Clear

'Initializes Surfer
	Dim SurferApp, Plot, MapFrame, ContourLayer, MapFrame2, ContourLayer2, ColorScale, ColorScale2 As Object
	Set SurferApp = CreateObject("Surfer.Application")
	SurferApp.Visible = True
	Set Plot = SurferApp.Documents.Add
	Plot.PageSetup.Orientation = srfLandscape

'===============================
'Variables
'===============================
MtoF = 3.28084
zMinM = 25
zMaxM = 100
zIntM = 4
zMinF = zMinM * 3.28084
zMaxF = zMaxM * 3.28084
zIntF = zIntM * 3.28084
'===============================

'Creates contour map from original grid file (meters)
	Set MapFrame = Plot.Shapes.AddContourMap(GridFileName:=SurferApp.Path + "\samples\demogrid.grd")
	Set ContourLayer = MapFrame.Overlays(1)

'Edit the contour layer
	ContourLayer.LevelMethod = SrfConLevelMethodSimple
        ContourLayer.SetSimpleLevels(Min:=zMinM, Max:=zMaxM, Interval:=zIntM)
	ContourLayer.FillContours = True
	ContourLayer.FillForegroundColorMap.LoadPreset("Rainbow3")
	ContourLayer.FillForegroundColorMap.SetDataLimits (DataMin:=zMinM, DataMax:=zMaxM)
	ContourLayer.ShowMajorLabels = False
	ContourLayer.ShowMinorLabels = False

'Add color scale and edit properties
	ContourLayer.ShowColorScale=True
	Set ColorScale = ContourLayer.ColorScale
	ColorScale.Title = "Elevation"
	ColorScale.TitlePosition = srfColorScaleTitlePositionTop
	ColorScale.TitleAngle = 0
	ColorScale.TitleOffsetHorizontal = -0.2
	ColorScale.LabelFormat.Postfix = " m"
	ColorScale.Left = 9

'Convert grid file to feet
  	Dim inGrid(1 To 1) As IGridMathInput
   	Set inGrid(1) = SurferApp.NewGridMathInput(SurferApp.Path+"\Samples\demogrid.grd", "A")
	SurferApp.GridMath2("A* 3.28084" , inGrid, "C:\temp\demogrid_feet.grd")

'Create new contour map
	Set MapFrame2 = Plot.Shapes.AddContourMap(GridFileName:= "C:\temp\demogrid_feet.grd")
	Set ContourLayer2 = MapFrame2.Overlays(1)

'Edit contour layer to have the same layer properties as for the other layer
	ContourLayer2.LevelMethod = SrfConLevelMethodSimple
    ContourLayer2.SetSimpleLevels(Min:=zMinF, Max:=zMaxF, Interval:=zIntF)
	'ContourLayer2.FillContours = True
	ContourLayer2.FillForegroundColorMap.LoadPreset("Rainbow3")
	ContourLayer2.FillForegroundColorMap.SetDataLimits (DataMin:=zMinF, DataMax:=zMaxF)

'Add a color scale to the new layer and edit properties
	ContourLayer2.ShowColorScale=True
	Set ColorScale2 = ContourLayer2.ColorScale
	ColorScale2.Title = ""
	ColorScale2.LabelFormat.Type = srfLabFixed
	ColorScale2.LabelFormat.NumDigits = 1
	ColorScale2.LabelFormat.Postfix = " ft"
	ColorScale2.Left = 8.4

'Turn off what you don't want to see
	MapFrame2.Visible = False
	ContourLayer2.MajorLine.Style = "Invisible"
	ContourLayer2.MinorLine.Style = "Invisible"
	ColorScale2.FrameLine.Style = "Invisible"
End Sub