Yeah, on their own patch, dogs can be more aggressive. They run to the fence when a dog walker goes by and they bark at the dog and the dog goes away. Obviously, because the dog walker is only passing the house and not coming to enter it but your dog doesn't know that. She thinks they went because she successfuly drove them away so she continues to do so. Thats why dogs often have a thing for the regular quick visitors like postmen etc...They come to the house, the dog goes crazy and they leave. The dog doesn't know they are only there to drop something off and leave anyway, the dog thinks they leave because they drove them away.
I know of lots of dogs round our end that go mad at passers by when they are in the garden but are fine when out on neutral territory.

Out in public, she probably won't be a problem. Correction isn't a great idea to stop aggression either. It tends to have the opposite effect in convincing the dog that the other dog really is bad news. They think they are being told off or whatever because of the other dog, not because of their behaviour, after all, it only seems to happen when another dog is around so it further convinces them to hate other dogs.
Feeding her some of her daily food rations in the form of treats each time you pass another dog in public is a good way to teach her that other dogs are good news, not bad, even if she's just had a go at the other dog. Yes, you might fear that this is rewarding her aggression but it isn't. If she was one of those types that went whappy whenever another dog passed out in public, if you started giving her a treat after passing every dog, she'd soon be too busy looking at you waiting for the treat when she saw another dog to be throwing herself aggressively at it.