## ImagePlot Axis

Posts: 2
Joined: 2012-06-17
Location: Switzerland

Hello,

Firstly apologies if this comes across as a stupid question, I'm new to IGOR (and a lone bastion of sanity amongst a department who insist on using excel for everything :S )

So, I have a problem making an ImagePlot from a series of XRD diffraction patterns Angle vs. Intensity (the angles are constant throughout the data). I made an image plot from this data (table of Angle, I1, I2, I3, I4, ... , converted to a 2D Wave and plotted as an Image plot). This gives me an image with the angle column (which i'd like to define as an x-axis) as a strip in the image, and the x-axis is in terms of "row number".

How can I define the X-Axis on an image plot to have values from the wave representing the (2Theta) angles?

Thanks

Posts: 910
Joined: 2007-06-21
Location: United States

If you have unevenly-spaced rows in an image then you can use a separate 1D wave to control the X axis of the image plot.

When you created the 2D wave you should have omitted the Angle column. Since it is in your 2D wave, you need to remove it. You can use Data->Delete Points to do this.

In order to use a 1D wave to control the X axis of an image plot, the 1D wave must have one more point than the 2D wave has rows. This is because the 1D wave specifies the X positions of edges of the pixels. If you think of a 1 pixel image, it has 2 edges. So you should duplicate your Angle wave and add a point to it. For information on this, execute:

`DisplayHelpTopic "Image X and Y Coordinates"`

If the rows in your 2D wave are evenly-spaced then you do not need and should not use a separate 1D X wave. In this case you should use the 2D wave's X scaling which specifies the centers of the pixels.