Even though my last thread on the topic didn't get much of a response I decided to continue my estimations of the size of parts of our GW world.
This was my method. I found a long, uninterrupted distance in Old Ascalon to run. I picked it because of the ease of killing things in my way. One assumption I made is that Vertical difference doesn't change the horizontal speed* I ran for precisely 20 seconds. Next I found the distance ratio between how far I ran and a larger stretch on the zoomed in World Map (1:7)** Then I found the ratio between that stretch and the overall dimensions of the world map (1:16.5 vert and 1:19.5 horiz)*** Some math later, I found the time to run the full length of the map to be 38.5 minutes vertically, and 45.5 minutes horizontally. Now, this corresponds to an incredibly small map. The fastest marathons (unofficial records here) ever ran are around 2 hours. So, given that our characters never get tired etc. the world map is about 8 miles across, and slightly less vertically.
End message: This place is tiny, but larger than cantha on a ratio of about 1.35:1. This ratio is an additional confirmation of the accuracy of my determinations, as the aspect ratios of the two maps should be equal, and then the ratio of vertical to vertical should equal the ratio of horizontal to horizontal. In my case they differ by about .1 which is not too bad considering my methods.
EDIT: Added Pictures
*I made this assumption based on a few trials, and that there is no Z-axis in the guild wars universe, the map moves under the player, the character model isn't actually moving at all.
**Zoomed in World Map
****Error analysis, see other thread, the error analysis is the same.