It’s springtime in Dallas and that means stormy weather. A quick check of WeatherBug's “Radar and Maps” gives me a snapshot of what’s overhead at the moment. Hitting the animation button, I have a sense of where the weather is from, its changing intensity, and where it is going.

Ah, the joy of “real time” data. We have grown to expect it. If I do a quick Web search of the phrase—“real time data,” I quickly end up with tons of links to places like the US Geological Survey for stream flow, NASA for ocean surface topography, NOAA for buoy data…and the list goes on.

But what about the production and dissemination of geographic data in the age of sail, horse, and foot in a world still marked by terra incognita? We can get a sense of it by using ArcGIS Explorer to investigate a map from the David Rumsey collection—the 1812 world map by John Pinkerton.

After launching ArcGIS Explorer, I opened the 1812 map service by going to File > Resource Center and clicking on the word “Historical” in the list of globes. Touring the map I begin to see what is there and what’s not in terms of geographic information for the period. For instance, focusing on North America, I immediately see a green area—the United States as of the Treaty of Paris, 1783. Surprisingly, the US map does not show the addition of the 1803 Louisiana Purchase. It also does not show topographic details from the 1804-1806 Lewis & Clark expedition, but does present some resulting stream details and names. (Note: The official expedition map was not published until 1814.) The Pacific Northwest coast and Western Canada, however, display rich detail from coastal mapping by George Vancouver and interior mapping by Alexander MacKenzie before the turn of the century. Both men, British explorers. North American Spanish territory is clearly hand-colored in yellow. Interestingly, British political geography for the period encompasses Lower and Upper Canada, Hudson’s Bay Company territory and then angles southwest from Minnesota to the San Francisco Bay, and all of then Russian America.

Besides the time it was taking to get new geographic information to cartographers, it also is important to note that this world map is the product of a British map maker and publishing house. How might these have affected the data they had access to and what and in what ways they chose to present them?

We’ll return to this map in a future blog posting.

- George Dailey, ESRI Education Manager