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| Buffer |
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A Buffer is the term used to define the area adjacent to some object, such as a map feature or a user defined shape. A buffer distance is supplied in the same units as the map data (feet, meters, miles, etc.) and a buffer polygon is created outward from the parent object. The buffer polygon can then be used to locate other map features that reside within the buffer distance of the parent object (when the buffer polygon is overlaid onto other map features they will touch). (Click here to see the button for creating a buffer.) |
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| GeoCoding |
Geocoding is the term used for determining a location along a measured network - typically this means locating a street address. Geocoding uses interpolation to locate an address - geocoded addresses are located at their theoretical location. If the address range of a street segment spans the address being geocoded, a point location will be created where that address should be. For instance, 197 will be located 97% of the way from the 100 end of the 100-199 block of Main St. (to be precise: 97 / 99 * 100 = 97.97%).
Interpolation also allows for addresses that do not exist in the real world to be "found". In the example above, there may not be a property or building assigned the number 197, but the geocoding process has no way to know that and will create an address location anyway. Another limitation is the network data used - if there inaccuracies in the street network, the geocoding process will produce unexpected results. (Click here to see the button for geocoding an address.) |
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| Map Extent |
A Map Extent is the bounding box that defines the area of a map being viewed. A Map Extent is defined in terms of the map coordinates comprising the corners of the bounding box, usually the lower left X and Y coordinates, and the upper right X and Y coordinates. Whenever zoom functions are performed, the current map extent changes to represent the current area being viewed. |
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| Map Sets |
Map Sets are a mechanism for storing the map's location (map extent) and/or map layer visibility settings. Map Sets may be private or public. Private Map Sets are saved by the user, and are available for a temporary time period (set by the site administrator). Public Map Sets are established by the site administrator and are available to all users. (Click here to see the button for working with Map Sets.) |
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| Pan |
The process of moving the current view of the map laterally, without changing the map scale. (Click here to see the buttons for panning.) |
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| Polygon |
Geometric term for a two-dimensional area. The minimum number of coordinates required to define a polygon is 3 (a triangle). Polygons can contain an unlimited number of coordinates and be irregular in shape. An example of a polygon is the land area of the state of California. |