## semi rings on the co-array map

This forum is dedicated to discuss all problems and suggestions related to the use of geopsy database and its plugins (array processing, H/V,...).
luigiV
Posts: 118
Joined: Fri Jul 17, 2020 9:28 am

### semi rings on the co-array map

Hi Marc,
how do you represent on the co-array map only the positive part of the rings?

Thank you

Luigi
Posts: 746
Joined: Mon Aug 13, 2007 11:48 am
Location: ISTerre
Contact:

### Re: semi rings on the co-array map

Hi Luigi,

If I correctly understand your question, the co-array plot is by definition from 0 to 180 deg. For each pair of stations, the direction of the vector joining the two stations is reduced to the interval 0 to 180 deg. If A and B are two stations, the vector from A to B is equivalent to the vector from B to A in the co-array plot. Each pair is represented by its direction from 0 to 180 deg and its inter-distance.

Best regards,

Marc
luigiV
Posts: 118
Joined: Fri Jul 17, 2020 9:28 am

### Re: semi rings on the co-array map

Hi Marc,
Sorry if I expressed myself in an unclear way, but the question is much more practical: how to represent only the positive part in the plot of the co-arrays. Working on the Property editor I could not find a way to remove the negative part and in the end to get only semicircles instead of whole circles.
Attachments
co-array.jpg
Posts: 746
Joined: Mon Aug 13, 2007 11:48 am
Location: ISTerre
Contact:

### Re: semi rings on the co-array map

Hi Luigi,

OK, I better understand your question. For these plots the X and Y axes are "Scaled", that is, their size is proportional to the difference between the max and the min value of the axis and to a user defined scale factor (by default the same for X and Y). The maximum axis value is controlled by the user in the properties box, however the minimum value of Y axis is controlled by the screen size of the window enclosing the plot. Resize the window so that the minimum reaches 0. Another way is to switch to "Total size" or "Axis size" for "Size" in properties "Y Axis/Scale". Then, set minimum Y to 0. Unfortunately, the X and Y scales are no longer equal which produced a deformed plot.

Best regards,

Marc
luigiV
Posts: 118
Joined: Fri Jul 17, 2020 9:28 am

### Re: semi rings on the co-array map

Hi Marc,
I followed your instructions both by modifying the scale factor to bring minimum y = 0, and by acting on the total size of the y axis. In both cases the ring is a deformed semicircle, as you said. I was hoping for Property box / object, but the dimensions of the object are not editable so I found a solution, for exporting the image of the rings, manually moving, with the mouse, the base of the window up to the value of y = 0 .
Therefore it would be sufficient to modify the default representation of the co-arrays (scale factor 1) to obtain the semicircles.
I also recorded that reopening Geopsy with different gpy files the program keeps the setting with the y axis = 0m for the co-arrays map.

luigi
Attachments
Mspac_rings.jpg