Plot new axes on intensity graph

[teroenzaa]

I am trying to draw XY axes through an arbirtary point on an intensity graph. I can draw two lines across the image (following posts like that linked below), but they don't seem to actually endf up a the coordinates I spesify. I know that I need to correct for the fact that the vertical scale increases from top to bottom, but how can I draw lines at the (x0,y0) position I spesify? It seems that the lines are overlaid on the image, but not linked to the actual axes of the intensity graph.

http://forums.ni.com/t5/LabVIEW/overlaying-XY-line-onto-intensity-graph/td-p/398963

[Artem.SPb]

you can use PlotAreaSize:

[teroenzaa]

Thanks. I'm still confused. I see that bounds was wrong because it found the size of the object, not nessesarily the plotting region. But PlotAreaSize seems to do the same thing. I want to draw a line at say (100,150) on the intensity graph, independent of the size of the chart.

Also, the options I get under the property node PlotAreaSize in my Labview appear to be different than in the picture you provided.

[Artem.SPb]

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@teroenzaa wrote:

Thanks. I'm still confused. I see that bounds was wrong because it found the size of the object, not nessesarily the plotting region. But PlotAreaSize seems to do the same thing. I want to draw a line at say (100,150) on the intensity graph, independent of the size of the chart.

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no PlotAreaSize - size of plot area only, Check it.

You need size of pixel in axis unit. So, you take plot size (pixels) and divide it to axis size.

Also, the options I get under the property node PlotAreaSize in my Labview appear to be different than in the picture you provided.

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You  can select any property in any order. You need axis size.
Btw, if your axis start not from 0, take range maximum and minimum.
Max-min=axis size

[teroenzaa]

Thanks so much. i think I understandnow.

Now I'll try rotating the lines by a user-spesified angle. 🙂

[Artem.SPb]

Degrees to radians and sine+cosine.
Or XY to polar -> change angle -> polar to XY

[teroenzaa]

Thanks. I ended up feeding the points into the 2D Cartesian Coordinate Rotation VI, but it's not right. I think this is because it is rotating about the origen and not the cursor point. I tried translating back to the origen, rotating, then translating back, and it seems to have a similar problem (forgive the dumb way I did that).

[Artem.SPb · Accepted solution]

but you need made "vertical mirror"

[teroenzaa]

I don't understand where  the "vertical mirror" comes in. I see that you convert to polar coordinates then add the angle (much more clever than my solution).

[Artem.SPb]

In my vi point(0,0) at left upper corner. You need left down.