Naming conventions for rows and columns

[calvin.harman@…]

The psImage struct uses mixed naming conventions when referring to pixel
locations: rows/columns and x/y coordinates. While a very minor problem, it can
become confusing and difficult to fix as both code and documentation grow over
time.

I'd like to propose we use row/column naming throughout both documentation and
code. (Row would be the y-coordinate and column the x-coordinate.)

[robert.desonia@…]

Follow-up question: we should try to be consistent in the order they appear in
function parameters, structs, etc. Given x=col and y=row, most of the functions
that used x,y as input now have col,row.

Would one prefer the order of row before col over col before row?

[eugene]

existing astronomy functions (ie, iraf, sextractor, etc) always refer to image
coordinates in the form (x,y) not (row,col). I believe all functions should
have the form OperateOnImage(image,x,y) in which case the x refers to a column
number and the y refers to a row number.

[eugene]

I have changed the psImage definition in the SDRS to use the union rows with
elements in the form rows_TYPE. Function parameters continue to be in the form
function(x,y)