A ZSE controller described issuing an IFR clearance altitude that placed the aircraft in an area below the MVA/MIA. The reporter suggested MVA/MIA altitudes be labeled on one video map as a controller aid.

Narrative

Aircraft X called asking for their IFR clearance. They had one on file. They reported 10 miles south of the airport. I gave them a discrete code. They were still not in RADAR. I took care of another aircraft while waiting to see their discrete code. I identified them and told them what altitude they were out of. They were only out of 084 (I think). I then issued a clearance to PIYOL (initial fix for the ILS) then direct. I asked them to advise when they had the destination weather and that he could expect the ILS; unless he had a different request. At one point; I did issue the current altimeter. There were two problems; I gave 080 as the altitude assignment when the MIA (Minimum IFR Altitude) is 090. However; that was the requested altitude. Also; they were slant/A and therefore unable direct PIYOL. Aircraft X questioned what 'PIYOL' was and I told them it was the definition of the fix. I realized that I gave the wrong altitude (about 30 seconds before the MSAW went off) and had already climbed them to 090. Aircraft X was always in the climb during the time I did this (or at least; that's what I remember). Aircraft X then turned due west and joined the radial and tracked inbound. I did not issue that clearance; but when I noticed them flying due west...I realized what they were doing. I chose not to correct them because I knew what they were doing. Aircraft X was safe at 090 on that heading and did not turn west until at altitude. They were shortly in a 075 MIA during flight. This aircraft always files /A. I do not know why I cleared them direct to PIYOL except that they were doing the ILS at the airport all day and thought I was providing a service. As for the MIA; I think that if we had the altitudes labeled on our MAP2 button; that it might have clued me in to the fact that I gave the wrong altitude.