September 08, 2010

High-resolution railroad maps online

Back in 2002, I stumbled across a company called TheHistoryCD. Among gobs of other offerings, the company advertised offered a collection of high-resolution scanned images of vintage railroad maps. I quickly grabbed the four-CD set and found the images had originated with maps in the Library of Congress.

The images were organized by state and collected into four main regions. The maps were all pre-1900 vintage. Many dated from the 1850s with some going back to the 1830s. Three even dated from the 1820s!

As advertised, the images were indeed high-resolution. Due to the scanned resolutions, the images would have occupied huge amounts of storage space, probably in the range of eight or ten DVDs had the images been uncompressed. The 4-CD collection of images was made possible by compressing the images using a proprietary format called "MrSid." While a cute moniker, "MrSid" actually stands for "multiresolution seamless image database". The format is now used quite heavily in the mapping business to store massive images such as color air photographs.

The problem with the collection was that the CDs were non-indexed. It was impossible to locate a desired map without cumbersome trial and error. I imagine that most users such as myself would have wanted to locate specific rail lines and that task might have taken as much as a half-hour or more.

For my own purposes, I extracted all the images and discovered there were 279 separate maps. The maps were extremely valuable as historical references, just really hard to use. Even with those shortcomings, I have wanted to recommend the collection to my correspondents many times over the last eight years. Unfortunately, TheHistoryCD company disappeared. Try as I may, I was never able to locate any alternate source for the images.

Until a few weeks ago.

It turns out that all the images originally found on TheHistoryCD set, plus many, many more, are available on the Library of Congress web site. They are found on a sub-site of the library called American Memory in a special section dedicated to railroad maps.

As best I can tell, the library offers 613 maps, all viewable online for FREE. You can also download entire maps if desired. There is a genuine mother-lode of information here for railroad enthusiasts!!!

As always, there is a downside.

Indexing on the Library's site is immeasureably better that when the maps were available in TheHistoryCD collection. Nonetheless, indexing is still greatly wanting. Searching by Keyword can help. Sadly, the trial-and-error method of browsing by Geographic Location is still probably the most useful. For instance, my hometown in southern Indiana probably appears on 15 or 20 maps, but the Keyword search only finds two. Similarly, searching for company names can work sporadically, but the prevelence of railroad abbreviations precludes general usefulness. Moreover, even when a map is located with the desired feature, the web site offers no help in narrowing down where in a given state or region the feature may appear.

It would be great, great, great is some obsessed person would index the maps the way we'd all like. That would take years, so do not expect any improvement over time. Still, the maps are a tremendous benefit to railroad enthusiasts, especially to those with patience.

No comments: