Very Confused

I am back to working on the Newman project. I decided to follow my idea from Bad Blogger posting and take a chunk of mock data and apply a mask in ra, dec, and comoving distance and then convert that data into x, y, z and feed it into my code (which is what I will be doing with the Sloan data).

Here is my masked data:

ra and dec mask

ra and comoving distance mask

These masks are funny shapes in x, y, and z (as to be expected):

Because the data is contiguous in ra, dec, comoving coordinates, I make the randoms in these coordinates and when I plot the data and the randoms you can see they fall int he same regions:


However when I translate these randoms into Cartesian coordinates -- using the same algorithm I used to create the data -- I get the following problem:


This is very confusing to me. I must be doing something wrong in the conversion, but I've checked this several times, so I don't know why it would be different now. AAAAAAAHHHHH.