Canvas is defined as follows: “(1) A heavy, strong cloth of various grades, used for sails, tents, etc. (2) A piece of such cloth; a sail. (3) A strong, closely woven cloth stretched on a frame and prepared for the reception of colors, as in paintings. (4) A painting. (5) A square-meshed fabric of linen, silk, or the like, on which embroidery or tapestry is worked with a needle. (6) A tent; especially, circus tent.”

When someone is talking about surveying an area, canvass is used. Canvass is defined as follows: “(1) The going about to solicit orders, interest, or votes. (2) A political campaign. (3) A survey taken to ascertain sentiment. (4) A detailed examination; especially, a sifting of votes in an election; a recount.”

Machine Briefs:
OPTION #1: canvas= KAN/VAS
OPTION #2: canvas= KAN/VA*S
OPTION #3: canvas= KWAS

OPTION #1: canvass= KA*N/VA*S
OPTION #2: canvass= KWA*S