|Help: Contents > Finding Resources > Selecting Categories|
The resources on GeoHistory have been organized and tagged in various ways. The categories tree on the left side of the page helps you find relevant resources by limiting the list of items to the criteria you select.
Categories are arranged in a hierarchical, expandable tree. To view sub-items of a particular category, click the plus icon . To collapse a particular part of the tree, click the minus icon next to the parent of the section you want to hide. Use the scrollbar to move up and down to view the whole tree.
To select a category, simply click the blue underlined link. Once selected, the category name becomes red and bold. To un-select a category, click it again, or click the "view all" link to reset selected categories.
Selecting multiple categories under the same main heading (Resource Type, Geography, Contributor) will display combined results for all categories under that main heading. For those familiar with library searching terms, this is a boolean OR operation.
Example: If you select Street Maps and Topographical Maps, both under the main heading of Resource Type, you will see all maps that are listed as either "Street Map" or "Topographic Map."
Selecting two categories under different main headings will only display those resources that are in both categories. This is a boolean AND operation.
Example: If you select Street Maps under Resource Type, and Philadelphia under Geography, you will see only Street Maps that are also tagged with as being of Philadelphia.
You can mix and match categories under different headings to craft your search. The criteria used displays at the top of the Search Results list.
Maps are tagged with the highest level area that appropriately describes the map. A map of the entire state of Pennsylvania, or a significant portion thereof, will be tagged as "Pennsylvania," not as any of the individual counties or cities shown. A map that is listed as "Philadelphia" will generally not also be listed as "North Philadelphia," even though North Philadelphia may be included on the map.
If you are doing research on a particular area of a city or state, make sure to look through resources that cover a wider range than the area you are interested in. For instance, if you are researching an area in Northeast Philadelphia, also look for citywide atlases of Philadelphia.