0. Match a sample towards a reference curve

First let's open the reference curve!

Click the menu command Collections/Create new collection from decadal file.

In the open dialog box, select the Namdo.rwl file in the demo directory in the directory where CDendro is installed and click Open. (Normally in C:\Program Files\Cybis\CDendro)

A collection with many members is created out of the Namdo.rwl file.

In this case we are going to analyze a sample named "NMBS05". This is an old file which is already contained within the Namdo.rwl collection.

It is not a good idea to have NMBS05 already as a part of the collection when we are going to check how well NMBS05 matches to that collection. Therefore we will remove the influence of NMBS05 on the mean values created from the collection.

Scroll down the list to find the NMBS05A sample and uncheck it!
Unchecked members in a collection do not take part in mathematical operations on that collection, e.g. they are not included in a mean value reference curve then created from the collection.

To create your reference curve, click the button "Create mean value sample".

A mean value sample is now created from your Namdo.rwl collection.

The light green curve in the middle of the green curves show mean values of "deTrended" ring widths for each year.

The thinner dark green curves around this mean value curve show the standard deviation found when the mean value curve was calculated.

The upper red curves show normalized values with the mean value curve in the middle and standard deviation curves around it.

Note:When you create a mean value sample from a collection, that sample is selected as your "reference" if there is no reference selected yet.
Use the "Select as reference" button on a sample window to make that sample the current reference.

What is deTrended ring widths? As good or bad soil influences the ring width growth of a tree, it is reasonable to divide measured ringwidths of a tree with some sort of mean ring width value(s) for that tree to make it possible to compare ring widths from different trees of e.g. the same age but with quite different stem diameters.

The mean ring width values used are normally taken from a negative exponential curve calculated for a certain tree. That curve gives you high values for the time when the tree was young and grew with wide annual rings. It gives you low values for the time when the tree became older and grew with much thinner annual rings.

Now open your coordinate file and run a correlation analysis between that file and the reference curve!

Click on the Workbench tab to see a tabular representation of the correlation analysis run!

The table is by default sorted in descending TTest order.
You may get it sorted in order of descending correlation coefficient value by changing a setting at Settings/Options for normalization and matching/Sort best matches...
Normally this gives the same result though as TTest values depend on the overlap, a high correlation coefficient value with a reasonably short overlap may not be "top-rated" when sorted according to TTest value.