I need to calculate the angles between two points on ArcGIS. I have ArcInfo License, too. I have 5 points on a diagram. One of them is my reference point. The other four creates angles between each other. I need to calculate each angle automatically. Because I have 7500 of these points. I'm also adding a picture of my points. I need to calculate the angles of point number 1-2, 2-3, 3-4, 4-1.
The Generate Near Table tool (under Analysis Tools > Proximity) will get you started. You can give the tool a search radius around your reference points and tell it to find the 4 nearest other points, it will calculate the distance and angle to each of the 4 points from the reference point. Make sure the Angle box is checked, Find Only Closest Feature is unchecked, and you enter the appropriate number of nearest points to find:
Once that's done you will have angles to each point from the reference point, so you'll need to do a little math to figure out the angles in your screenshot. The Near tool calculates angles relative to the X axis so an angle of 0 would be due east, 90 would be north and -90 would be south.