Rectangular Target - 2013: Y Axis inverted?

I’m running the Rectangular Target - 2013 on my computer (not the cRIO) with the sample images.

The screensteps documentation (, the section on “Position”, diagram “Aiming Coordinate System A x,y”) indicates that Y=-1.0 is the bottom of the frame, but the data I am getting back is Y=-1.0 is top of the frame.

HybridLine_SmallGreen2 has two targets at (0.50625, 0.120833) and (-0.1625, 0.0583333). hmmm, the 2nd (leftmost) target looks higher in the frame to me, but has a small Y value.

I made a copy of HubridLine_SmallGreen2 with the targets almost at the top of the frame, the target coordinates change to (0.50625, -0.779167) and (-0.1625, -0.854167). Higher in the frame, but smaller Y value (almost -1.0).

Am I doing something wrong, or are the docs wrong?

I ran the LV example, and if you click on the fourth image, it is pretty clear that Y axis has -1 at top and 1 at bottom.

Greg McKaskle

ah. Docs are wrong. Who do we contact at WPI about that? :slight_smile:

It is stored at WPI, but may have been written by someone from FIRST. Perhaps the best place is to file a tracker on

Greg McKaskle

I’ll try, but the best fit I can find would be to file a tracker against WPILib.

It’d be good if the screensteps had a “send corrections to …”

There were several trackers filed for screenstepslive documentation related to Java in the WPILib Java tracker on FIRSTForge. They were fixed. I’d recommend putting your comments on the LabVIEW vision documentation in the LabVIEW section in the WPILib Tracker.

I’m not seeing a place to leave comments or any feedback. What am I missing?

Sorry, I realized I left out a few important words. I edited the original post. I was refereing to the LabVIEW section of the WPILib Tracker on FIRSTForge.

…and FIRST just fixed the docs.