Log wt % output

[Malcolm Roberts]

I’m trying to fathom log wt % output in calcimage. A user has asked for this to highlight variation at low cons. However, I can find no information on what the transformation entails as I cannot match corresponding values between the normal wt % and the log wt% values. There is no info in the calcimage v10.4.5 user guide nor seemingly on line. Not even GS discussion forum has anything. Attached two images as an example. Ignore the pen marks……
Cheers,
Malc.

[John Donovan]

I’m trying to fathom log wt % output in calcimage. A user has asked for this to highlight variation at low cons. However, I can find no information on what the transformation entails as I cannot match corresponding values between the normal wt % and the log wt% values. There is no info in the calcimage v10.4.5 user guide nor seemingly on line. Not even GS discussion forum has anything. Attached two images as an example. Ignore the pen marks……
Cheers,
Malc.

Hi Malcolm,
Here is the code I'm using to calculate log wt%. It's just the natural log! Best to open the .dat file in Excel to check the actual data.
john

' Save log weight percent results to LogWeightPercentData
If CalcImageCalculateLogWeightPercentsFlag Then

sum! = 0#
For i% = 1 To CalcImageOldSample(1).LastChan%
sum! = sum! + CalcImageAnalysis.WtPercents!(i%)
If CalcImageAnalysis.WtPercents!(i%) < MINIMUM_WEIGHT_LOG_VALUE! Then CalcImageAnalysis.WtPercents!(i%) = MINIMUM_WEIGHT_LOG_VALUE!
CalcImageAnalysis.CalData!(1, i%) = Log(CalcImageAnalysis.WtPercents!(i%))
Next i%

' Store log weight percent (if sum is greater than MINIMUM_SUM_WEIGHT!)
For i% = 1 To CalcImageOldSample(1).LastChan%
If sum! > MINIMUM_SUM_WEIGHT! Then
tLogWeightPercent!(i%) = CalcImageAnalysis.CalData!(1, i%)
Else
tLogWeightPercent!(i%) = BLANKINGVALUE!
End If
Next i%

[Malcolm Roberts]

Thanks John
I had my suspicions that it might be natural. Good to know.........
Cheers,
Malc.

[Malcolm Roberts]

John..... Would it be possible to get a log base 10 option? I am pondering ways of dragging out subtlety in data sets and though this might work.

[Probeman]

John..... Would it be possible to get a log base 10 option? I am pondering ways of dragging out subtlety in data sets and though this might work.

Hi Malcolm,
I'm pretty sure that both log base methods would give the same visual result.   Can you perform the two different log calculations on the quant (elemental) output .dat file and see if they look any different in Surfer?
john

[Malcolm Roberts]

I've give it a go.... Watch this space......