Aerial Photography - Photographs of the earth's surface taken from a platform flying above the surface but not in orbit, usually an aircraft.  Aerial photography is often used as a cartographic data source for base-mapping, location of geographic features, and interpretation of environmental conditions. 

Overview Map - A generalized, smaller-scale map that shows the limits of another map's extent along with its surrounding area.

Zoning - The application of local government regulations that permit certain land uses within geographic areas under the government’s jurisdiction. Zoning regulations typically set a broad category of land use permissible in an area, such as residential, commercial, agricultural, or industrial. Zoning regulations can also set constraints on building construction within areas, which may affect factors such as the maximum height of structures, minimum setbacks from property lines, amount of parking that must be provided, or the density of housing.

Zoom - To display a larger or smaller region of an onscreen map or image.

JPEG - Acronym for Joint Photographic Experts Group. A lossy image compression format commonly used on the Internet. JPEG is well-suited for photographs or images that have graduated colors.

Lossy Image Compression - Technology that attempts to eliminate repetitive or unnecessary information.

Bitmap - An image format in which one or more bits represent each pixel on the screen. The number of bits per pixel determines the shades of gray or number of colors that a bitmap can represent.

Plug-In - A small software application that extends the functionality of a Web browser.