canopy cover material?

where do I find suitable material for making my own custom canopy cover?
no disrespect to those doing it commercially, but I'd rather sew one
myself. that way I know it fits exactly, where the straps are, etc.
the glider sits rigged in the California/Nevada sun and occasionally
gets rained upon. I made one out of inexpensive fabric store material
and it lasted 4 seasons, but now it's in tatters and only suitable for a
pattern.

any pointers would be appreciated.

Ken
San Jose, CA