Friday, May 25, 2012

Looking for Local History: Fun with GIS


May is local history month! All month long, we'll be sharing bits and pieces of Issaquah's collection, as well as tutorials to help you find local history on your own. Enjoy!

Many of the research requests we receive revolve around questions about where things used to be located, or what the area looked like before. One of the niftiest features of the King County iMap is it's ability to layer different information onto one map. Using iMap, it's possible to look at a current road (and parcel) map superimposed with the 1936 aerial image, to see what changes have occurred in the roads or landscape.

1. Start iMap and locate the property you're interested in (see our previous blog post for more information on how to find a property using iMap).


2. Once you've found the parcel map for your property, take a look at the checkbox options on the left. You can experiment with these options to increase or decrease the amount of information that is layered onto your map. At the bottom of the list is “Imagery.” Expand this item so you can see your options. Select 1936 aerial view.


3. Here we see current parcel boundaries laid over a 1936 black and white aerial photograph. See that large property with the two diagonal sidewalks? This is the Issaquah High School in 1936. Today, the Issaquah Community Center is located on this lot.




4. Here we take a look at the Issaquah Highlands. In the first map, current roads are laid over the 1936 aerial image, and contour lines have been added to show elevation differences. In the second map, parcel boundaries have been added to show properties:




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