FORCinel: Quick Start Guide
The FORCinel Menu
Load FORCs: Loads standard Princeton FORC files.
Display FORCs: Plots the raw FORC curves. Enter a number n to display every nth FORC curve.
Process FORCs: Converts raw FORC curves into a FORC diagram.
Change Smoothing Factor: Use to change the smoothing factor of an already processed FORC diagram.
Remove All Smoothing: Calculates the FORC distribution from the raw data with no smoothing at all. Useful to see if features in the FORC diagram are real or just processing artifacts. Note this feature is also available from the Data Masking panel.
Display Processed FORCs: Display a FORC diagram (assumes Process FORCs has already been run on that data folder).
Contours...: Adds Contours to the FORC diagram. Once you have the contour plot looking just right, you can choose Convert Contours to Flat Colours to make the image colours inbetween contour levels constant (similar to a Mathematical style FORC diagram).
Add Colour Scale: Adds a colour scale to diagram. Double click the scale to make adjustments.
Autoscale Intensity Range: Scales the range of colours used for plotting to match the maximum and minimum values of the FORC distribution in a selected area (you must manually select a region of interest on the FORC diagram before selecting this option; see Step 8 above).
Autoscale Contour Range: Scales the range of contour values to match the maximum and minimum values of the FORC distribution in a selected area.
Reset to Default Intensity Range: Sets the range of colours used to match the maximum and minimum values of the FORC distribution in the area of the original measurement.
Reset to Default Contour Range: Sets the range of contour values used to match the maximum and minimum values of the FORC distribution in the area of the original measurement.
Convert to Greyscale: Converts FORC diagram to greyscale (e.g. for publication).
Coercivity Profile: Plots a horizontal profile of the FORC distribution at a specified value of Hu.
Vertical Profile: Plots a vertical profile of the FORC distribution at a specified value of Hc.
Averaged Vertical Profile: Plots a vertical profile of the FORC distribution averaged over a specified range of Hc values.
Marginal Coercivity Distribution: Sums each vertical column of the FORC distribution to obtain a coercivity distribution.
Normalise FORC Distribution: Normalises the FORC distribution by dividing each vertical column by the maximum value in that column. This procedure was proposed by Egli (2006) JGR doi:10.1029/2006JB004567, and is useful when quantifying the distribution of interaction fields in SD samples. Use the Vertical Profile or Averaged Vertical Profile options to see the distribution. To get back to the unnormalised FORC diagram, simply choose Change Smoothing Factor.
Drift Measurement: Plots the drift measurements from FORC file.
Reversible Ridge: Calculates the reversible ridge directly from the measured data.
Data Masking Panel: See Advanced Features.
Mask Area: See Advanced Features.
Calculate Optimum Smoothing Factor: Uses the method of Harrison and Feinberg (2007) to determine the optimum smoothing factor. Enter a starting SF, finishing SF and increment value. The program calculates the standard deviation of the fit residuals as a function of SF and identifies the point of inflection. Warning: this value should be taken only as a guide - ultimately the user must decide what is an acceptable degree of smoothing! Weak signals with a high level of noise may require a higher value of the smoothing factor than indicated by the minimum in the derivative plot. You should manually examine the derivative plot to see how well defined the minimum is. A flat, poorly defined minimum is often obtained for very noisy data, indicating that a higher value of the smoothing factor can be chosen without introducing bias in the plot.
NEW FEATURES: See the FORCinextras menu to plot FORC diagrams in 3D, extract Day Plots directly from your FORC data, and obtain an IRM aquisition/gradient plot!
Last updated on 04-Sep-09 09:25