CooRecorder basics

Last update 19 March 2021.

For a video introduction on measuring tree rings with CooRecorder see "CooRecorder Tutorial" by Stockton Maxwell at Radford University.

Please notice that this video now has the English subtitles. You can turn on the subtitles through the settings command in the lower right corner. Also note that you can reduce the Playback speed to e.g. 0.8 if you think that the video is running too fast.

(There is an alternative link at Vimeo: "CooRecorder Tutorial")

Here comes a follow-up by Stockton Maxwell with additional tips on using CooRecorder:
CooRecorder Tutorial Part 2

Here comes another introduction by Stockton Maxwell, now on using CDendro:
CDendro Tutorial

The CooRecorder program is used for registration of coordinates collected from images.

You can use your scanner to scan not only photos but also anything that can be placed on top of your scanner. An image scanned as from a photo from such a thing can then be displayed on your computer screen. You can enlarge the image to see interesting details and you can write down coordinates of these details. It is a very tedious task to do this very manual registration if you have an interest in lots of data for later statistical analysis.

Our CooRecorder program solves the problem by letting you just click on interesting points in your image. The coordinates of these points are then automatically written onto a file which you can later analyze with another program.

When do I use the program?

I do have this registration problem for two of my own interests: Bee-keeping and Dendrochronological analysis.

Breeding for better bees. For bee keeping it is a matter of measuring characteristic data from bee wings. This data may tell if the wings came from bees of a pure breed or from a mixed up breed or from some special breed. Mixed up bees are often angry. A bee keeper tries to avoid having angry bees, because they annoy his neighbours and he gets stung by them. Identifying a breed is also a matter of breeding for a lot of other qualities than just non-aggressiveness.

Dating old houses and other constructions of wood. For dendrochronological data it is a matter of measuring the width of tree rings. A long sequence of such widths from a tree sample can be used to find out which year the tree was cut. I.e. to find out when an old house was probably built.

Working procedure when using CooRecorder

Click on File in the menu bar and select "Open image file for new coordinates". Select one of your .jpg, .gif, .bmp, .png or .tif files.
When the file is loaded, a new window comes up.
Set the appropriate DPI value and select Raw data (for e.g. measuring bee wings) or
Sorted data for dendrochronological measuring of yearly tree ring width.

There are five buttons (and two scrollbars) to control the view of the image:

Note: Put the cursor over a button to see the tooltip.
A magnifying glass, a demagnifying glass, a fit on screen button, an actual pixels button and a hand tool button (for dragging the image over your screen). The scroll bars are only shown when the image does not fit on the screen.

To the left of the magnifying glass is a percentage indicator showing the current magnification of your image. 100% means that one pixel in  your image is shown as one pixel on your screen.

The magnification glass is a "zoom in" button. First click on the button. Then click on the appropriate point in your image. The view will zoom in an extra 50%. Click again to zoom more. You can set the magnification as a percentage number if  you click in the field to the left of the magnification glass. Click on the demagnifying glass to zoom out of the image.
The magnification and demagnification glasses are also available through the Z button and the Ctrl-Z button on your keyboard.

To drag the image over the screen, first click on the hand tool button (or press the H key). Then click on a point in the image and keep the mouse button pressed down. Then move (drag) the mouse with the button still pressed. (The hand tool is only enabled when the image is magnified so it does not fit on the screen.)


Recording aims at getting coordinate pairs registered on rows (lines) in a file, like here with seven pairs on each row:

Example: Coordinates measured from two bee wings.
11.40 2.37  14.80 2.57  12.69 2.60  11.88 2.61  12.71 3.24  13.32 3.52  13.56 3.50  12.77 4.18
10.71 6.24  14.13 6.70  12.03 6.58  11.16 6.48  12.10 7.25  12.51 7.50  12.73 7.49  11.89 8.11
Note: The decimal separator used above is that of your Windows/Settings/Regional options/Decimal symbol to make the data compatible with your spread sheet program.

When registering coordinates from a tree sample, there is (normally) only one coordinate pair to register for each ring border. The registered coordinates are written to rows in a file like this:

Before you start recording you have to click the Data button which will then "light up" with a red border:
(You may also press the D key on your keyboard.)

Recording modes

There are basically two recording modes in CooRecorder:

  One coordinate pair for each written row of data to the file or

  a group of coordinate pairs for each written row of data to the file (data group mode):

If you are using the data group mode you have to click the End of data group button before you start recording the next group of coordinate pairs:

End of data group button

If necessary, you may switch between  these two modes while recording. For fast switching, you can click the right button on your mouse to do this.
You may use the Enter key as a substitute for the End of data group button.

Start recording by clicking on points on your image. The recorded points will be marked with plus signs. This is an example of measuring dendrochronological data where the coordinates will be written as one point per row (i.e. one coordinate pair per data row in the file)

Note: When using CooRecorder to measure dendrochronological data, measurement should start at the outermost ring of the tree and continue towards the inner part of the tree! (Please do not try to do it the other way, because that will make CDendro sort your rings with your oldest ring handled as your youngest ring.)

Note:Below the magnifying glass tool, there is a small frame showing current coordinates in millimetres. The number of decimals shown are the same as the number of decimals written to the rows of the data file. This can be changed through the menu command Settings/Other settings.

There are a number of buttons for editing what you have recorded:

A select button to select a certain point.
Click on the Select button, then click on the proper point. When a point is selected the editing buttons will be enabled. They are otherwise dimmed. They are shown enabled above, because a point is selected in the image.
You may use the S key on your keyboard instead of clicking on the Select button!

A replace button.
First select a point. Then click on the replace button (or press the R key) to enter the replace mode. Finally click at the new registration point in your image. This will move the selected point.

Note: From version 7.8 of March 2014 you may use the "Ctrl-arrow-key buttons" to stepwise move the selected point in any of four directions!

There is a delete button - the black cross.
This button will delete the currently selected point. If this point is part of a group, the whole group will be deleted. This is done so because deleting a point inside a group will probably make the order among the remaining points unclear. If you want to change some data within the group, either use the replace button to move individual points or use the delete button and then reregister the whole group.

There is a disable button - the red cross.
This button is used to disable single datapoints. When they are later written onto the file a "D" will be written directly in front of the numeric coordinate pair. This is usable for dendrochronological data, where some visible tree-rings are not actual year rings. You may want to register such an unclear point though you want to have the coordinate pair disabled until you know more about the sample. You can open the coordinate file later, select the disabled point and then click again on the disable button to enable the point.

There is also a start point button.
Normally the first coordinate you click when recording is also the first coordinate to be written to your file. Though when working with dendrochronological data you may want to register some extra points later. Or you want to delete the original first coordinate pair from your data set. Then it may be appropriate to indicate which point is the very first point of your data set. This button is only enabled when you are working in dendro mode and when you have also selected a point with the Select button (the button with the big arrow).

Writing your data to a file

Use the File/Save As command on the menu bar!

Output formats

There are three output formats: Raw data, Sorted data and Dendro with seasonwood.

When you open an image file, you also have to decide which output format to use. Anyhow you may change your choice with the "Set DPI and data-type" button.

Raw data is what you would suppose it to be: Data taken from your first registration point and forwards until your last registration point. This mode will ignore any start point settings. Here is again the example from two bee wings:
11.40 2.37  14.80 2.57  12.69 2.60  11.88 2.61  12.71 3.24  13.32 3.52  13.56 3.50  12.77 4.18
10.71 6.24  14.13 6.70  12.03 6.58  11.16 6.48  12.10 7.25  12.51 7.50  12.73 7.49  11.89 8.11

Dendro data or sorted data is written from the starting point which you may redefine with the Start Point button. Then the next point written is that which is nearest to the start point. Then the point nearest to that point until there are no more points. In dendro mode, coordinates are always written with decimal POINTs and with a comma between the x- and y-coordinates, like
This format can be read by our CDendro program!

Note: If that format is not what you want to import into a spread-sheet-program, you can always select the raw format before writing out your coordinates:
108.16 6.03
107.97 6.04
107.48 6.06

Dendro Seasonwood data is a bit more special. When you need to know more about that format, please look into a file of that type.

Using a HelP line to measure along a line

You may set sort of a ruler/Help line/Support line. You can then measure along that straight line! To make the help line drawn, first click on the help line icon as shown above or press the P key on your keyboard. The icon will then light up as shown below.

When the help line is being set, a perpendicular crossing line is also plotted. When that crossing line is parallel with the tree rings, you have the best position for your line.

DataH-mode - A "cursor" to help you measure perpendicular across the next ring

The "DataH-mode" is available (toggle) by right-click on the D-icon. It will give you a "cursor" with perpendicular help lines growing from a previous already selected point towards the next point to set.

Basics on measuring tree rings - on changing the measurement direction

Note: For information on how to change the measurement direction ("changing the measurement path"), see the section "How to measure at right angles or over a crack".

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