Historic Pelham

Presenting the rich history of Pelham, NY in Westchester County: current historical research, descriptions of how to research Pelham history online and genealogy discussions of Pelham families.

Monday, February 14, 2005

Studying Antique Maps of Pelham Using Online Services That Provide High Resolution Scans -- Part I

There are a tremendous number of online resources that offer high resolution images of important maps showing Pelham and surrounding areas from the 17th century to the present. Any serious student of local history can find important historical maps that can be magnified to sizes larger than the original. Often free software tools may be used to maintain the scale of the original map as the image is resized so that important distances may easily be determined. For genealogists, many of these old maps reflect the owners of properties depicted on the maps.

This posting will be the first in a series of postings that will describe how to access and utilize such maps from online services such as those offered by The Library of Congress, The New York Public Library and many other sites such as DavidRumsey.com. Part I will address the map collections maintained by The Library of Congress in its online "American Memory Collection".

The Library of Congress American Memory map collection may be found at http://memory.loc.gov/ammem/browse/ListSome.php?category=Maps. It contains seven categories of maps including civil war maps (1861-1865), Liberia maps (1830-1870), maps (generally - 1500-2004), National Parks maps, Panoramic maps (1847-1929), Railroad maps (1828-1900) and Revolutionary Era maps (1750-1789). For students of Pelham history, I have found the Maps (general, 1500-2004) and Revolutionary Era maps (1750-1789) collections to be particularly good, although there are relevant materials in some of the other categories as well.

We will use the Maps (general, 1500-2004) collection as an example. By clicking on that link on the American Memory maps page, you will be taken to the following location: http://memory.loc.gov/ammem/gmdhtml/gmdhome.html There you can browse maps by category, although I prefer to search for maps. At the bottom of that page you will see a link entitled "Search by Keyword". By clicking on that link and following the simple instructions on the search screen, you will be able to perform keyword searches. Try "Westchester", for example. You should see a set of 8 search results returned including some important early maps of Westchester County that show the area surrounding Pelham. Don't limit yourself to searches for Pelham and Westchester. Searches for "New York" and even browsing the collections for early maps of the Atlantic cost of North America reveal important early maps that show Pelham and surrounding areas.

Most important is the technology offered by the Library of Congress for studying the maps you have found. Click on any of the search result links to look at a map of Westchester. You will notice that you are first taken to a bibliographic page providing information about the map you have selected as well as a thumbnail image of the map. If you click on the image of the map, you will be taken to a page with a "Zoom View" and a "Navigator View" of the map. You can easily magnify the map and select portions that you wish to analyze more carefully. Don't stop there, however.

Notice that at the very bottom of the page there are links entitled "Download MrSID image" and "View more information about the MrSID compression technology". The Library of Congress and many other such institutions use an image compression technology known as the MrSID compression technology for delivering images of maps online for academic analysis. The technology allows users, using ordinary home computers, to magnify images of maps to many times their original size, to export high resolution images of all or any portion of the map for printing or other purposes, and to preserve the original scale of the map no matter what size is viewed (among many other things). Most interestingly, this can all be done offline simply by downloading a free copy of the MrSID image from the Library of Congress Web site and also downloading a free copy of the MrSID compression technology software available from a company known as LizardTech available via links on each map page in the Library of Congress American Memory map collections. To learn more about the free MrSID browser plugin offered by LizardTech, you can go directly to http://www.lizardtech.com/download/dl_download.php?detail=geo_expressview_plugin&platform=win and downoload it from there.

Once you have downloaded the MrSID software, you can save from any of the map pages on the Library of Congress site a high resolution copy of the map(s) in which you are interested by clicking on the links entitled "Download MrSID Image" and, when prompted, instructing your system to "Save" to a location of your choice on your computer hard drive (e.g., your "My Documents" file). Once you have done so, open the MrSID software and select file > open then browse to the map file you saved and open it. Using the button that looks like a magnifying glass you can begin magnifying and browsing the map you have selected whether you are online or not. The software is rich in its functionality, so you will have to explore it for its features. You can use it, however, to find Pelham and its roads, properties and topography during a host of different times from the 17th to the 20th centuries.

During the next few days I will blog about some of the additional online map collections where important maps of Pelham and surrounding areas may be found and analyzed using the MrSID software.

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