Location Based Scanning Features
From The RadioReference Wiki
If you connect a GPS unit to the scanner, it can automatically enable/disable systems based on the geographic information you provide:
- Latitude (center of the range)
- Longitude (center of the range)
- Range (radius of a circle around the Latitude/Longitude) which can be selected from .5/1/3/5/10/20/30/50 miles.
When the scanner is within the "circle of coverage" defined for a site or system, the scanner will automatically unlock and scan the site or system. When the scanner moves outside the "circle of coverage", the site or system will automatically be locked.
Rather than center the lat/lon on the antenna site for the system and set the range to the receivable range for the system, it makes more sense to center these settings on the geopolitical center of the system, and bound the range to encircle that entity. That is, while one can technically hear the Arlington TRS from west Fort Worth, you might not want to. Instead, set the lat/lon/range values to approximate a circle around the Arlington city limits so that Arlington wouldn't be heard until you approach it.
Also, not all geopolitical areas are perfect circles. You can modify the shape of the system by entering multiple sites for the system (even though the system might have only one site) and use different location settings for each site. For example, stack two circles to make a tall, narrow scan area for the system.
Location Based Features
The scanner can display information or provide an alert when certain location requirements are met. The following are the types of location features allowed.
- Dangerous Xing (DXG): Stores location, range, direction of travel. If you are within range, traveling in the specified direction, you receive an alert.
- Dangerous Road (DRD): Stores location, range, speed. If you are traveling at a speed greater than the one specified, and are within the range of the specified location, you receive an alert.
- Points of Interest (POI): Stores location and range. If you approach the specified location, you receive an alert.
- See the DRD_DXG_POI for points defined in this wiki
- Also see Population Area Centerpoint
In general, a location alert can have:
- Speed (optional)
- Alpha (optional)
- Alert Type and Level (optional)
- Vector (optional)
Alerts are based on:
- Speed setting > 0 and no vector entered, non-directional speed alert
- Speed setting > 0 and a vector is entered, directional speed alert
- Speed = 0 and vector is entered, dangerous intersection alert
- Speed = 0 and no vector entered, point-of-interest alert
The user can quickly save a location by pressing GPS. Scanner prompts for the type of location to store (Speed, Intersection, or POI).