Arrow 'points' to right axis fixed to a marker

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Thu, 03/07/2013 - 08:04 pm

Hi Guys,

I am using the lovely Igor pro for some graphs, and can't seem to figure out how to do something.

I have a graph with a left and right scale, and one data set that relates to the right scale. I would like an arrow to point from one of the markers to the right legend (to show that the market set relates to the right legend). I can draw one in using the tools, but if I change the size of the graph or the scale of anything it will then be in the wrong place.

Is there a power which allows me to attach it to a marker? The picture explains what I'm after: http://imgur.com/OJ9nJIk

Thanks
I forgot I was after one more thing... I would like to have different colored sections of the graph background. Again I could make a box of a color, but if I move anything then it will lose its position. Similarly to the arrow, is there a way to fix them so I can re size the graph and they will stay in the same locations?

This is an example of what I would like: http://imgur.com/ck6pE2z (the brown boxes are just an example of colored sections I would like)

Thanks Guys

March 7, 2013 at 08:16 pm - Permalink

Hi Steve,

You can draw these objects (the shaded areas and the arrow) with the tools menu. Show tools with command+t. When you draw you can specify to fix to the axes and define the points. This gets around any issues with resizing. You can draw in the front or back of the graph by option clicking the picture of the tree and selecting userback (or whatever). The legend you also need to freeze in place. I am actually not sure how you do this (I know how to freeze it, but not how to plot the top corner relative to say bottom and right axes, which is what you need to do). Maybe somebody else will chip in.

March 7, 2013 at 11:56 pm - Permalink

After you have drawn any object (arrow, box, whatever) double click it with the select tool. There the first (top left) option you see is the coordinate system for the positioning. You have 4 options:
Absolute = positioning in Igor points (sort of pixels)
Relative = percentage of graph size (between 0 and 1)
Plot Relative = percentage of plot area (between the axes)
Axis XX = fixed to axis values

What you want is the last option for the right axis.

March 8, 2013 at 02:54 am - Permalink

chozo wrote:
What you want is the last option for the right axis.

Well, to keep the arrow in place horizontally, he needs to choose X coordinates as Axis coordinates associated with (most likely) the bottom axis.

The arrow should most likely also have Y coordinates set to Axis and using the right axis.

The colored boxes, in order to maintain fixed horizontal location should use Axis coordinates with the X axis (most likely bottom). To make a shaded box that spans the graph from top to bottom, choose Plot Relative for the Y coordinates, and set the Y0 to 0 and Y1 to 1.

You may also wish to set the line thickness to zero so that you don't have an outline around the colored box.

Finally, to avoid covering axes and traces with the colored box, you will want to put the box in the User Back drawing layer. Hold down Option (Macintosh) or Alt (Windows) while clicking the tree icon to get a menu of drawing layers.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com

March 8, 2013 at 09:18 am - Permalink

Thanks guys, I got the arrow working, I just set it in place, then chose axis right and the same point where the marker is at, looks great.

Same with the boxes, once I figured out the X and Y axis coordinates it was quite simple. Igor is truly powerful!

March 12, 2013 at 01:23 am - Permalink