Subchapters:

Working with arraysThere is a lot of operations on arrays, have a look to the manual. The last one presented here will be total.: IDL>
proj1 = total(image1,1) Here the proj1 and proj2 are vector resulting of the sum of the image1 on the x and y axis respectively. It can be seen as a projection along a direction. You can normalize it by: IDL>
proj1 = total(image1,1) / (size(image1))[1] The grand_total is the sum of all the elements of image1. The mean of the array is: IDL> mean = total(image1) / n_elements(image1) But can also be obtained by: IDL>
print,moment(image1) The first element is the mean: IDL>
print,(moment(image1))[0] 
IDL courses C. Morisset © 2004 IA/UNAM V 2.2 