I think at the moment she's probably working on the 46 week developmental spurt - there was a previous one around 37 weeks, which causes the 8/9 month sleep regression (which often continues through till 11 months).
When babies are working on a developmental spurt is the worst time to try sleep training of any sort - their minds are buzzing so much they simply can't stay asleep.
There's more info here, here and here.
11 months is relatively young to be on only one nap, and 1 hour sounds very short to me - she could be suffering from lack of daytime sleep. (Night sleep being worse if you reduce her nap suggests she could be on the edge of overtiredness normally.) How long has she been having just the one nap?
Could you try to get her to nap a bit earlier and let her sleep at least 2 hours, more if she wants to?
Alternatively, you could try for two shorter naps - if she wakes around 7ish, 9am and 1pm are good times to try.
I'd also recommend teaandcakes' suggestion of the Marc Weissbluth book, although IMO it's poorly written, badly organised and I think his 'cry it out' regime is cruel. But all the stuff on nap schedules is the most useful I've come across.
What time does she normally get up / nap? Does she ever drop off in the pram / car in the mornings?
It sounds like she increases tension by crying so if you do want to do some sort of 'sleep encouragement' (I hate the word 'training'), I'd wait till she's past 46 weeks past her due date, and then try some of the Baby Whisperer methods, or ideas from the No-Cry Sleep Solution. Controlled crying etc usually is pretty awful for a baby who increases tension by crying.