I didn't realize it had been so long since you were there!
If you can picture the esplanade (and I don't nkow if you can...before we went in '05 I hadn't been since I was a child and had absolutely no memory of what it looked like before.
Anyway, if you were a bird up in the sky, facing
disneyland itself, you would be over the esplanade.
Behind you would be the entrance to DCA.
If I have my brain on straight, your RIGHT wing would point towards Harbor, though a person wouldn't see Harbor since they would be standing on the ground (being a bird has its sight-line advantages)...what the person would see is the ticket booths on that side. Beyond the ticket books are little "tents" or marquees, covering tables where you put your bags to be checked by "security" AKA "bag check". Beyond those tables is the tram pickup/dropoff area, then outside that the cab area, then there's Harbor.
Your birdy LEFT wing, however, would point towards DownTown Disney. But if there were a person walking on the ground (trying to get away from the pigeon strangely hovering above the esplanade, perhaps), that person would see the other side's bagcheck/security, between the esplanade and DTD.
So either way you come into the esplanade a person has to go through bag check. It's not a big deal, you just open your purse/bag/camera bag/whatever and they squeeze the bottom and look inside. When you are exiting, going out to Harbor or DTD, you just find the Exit line...you don't get checked leaving the area.
You might want to have some fun on googlemaps using the mixed street and satellite views, it's fun to really see what's going on. Get the main Disneyland address, center the view on what you want to see, hit the + button to zoom in...might help you with my bizarro birdy-view story.