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About Lat/Lon Coordinates and Grid Squares
Last updated Thu Nov 13 10:36:26 MST 2008

In this section:

  • Basic Facts about QRZ Coordinate Data
  • About Grid Squares
  • How to modify input new coordinates

Basic Facts about QRZ Coordinate Data

For USA amateurs, the lat/long and grid squares listed are presented using one of three methods. First, QRZ uses the 2006 TIGER/Line data from the US Census department to perform geododing of the listed FCC address. This method determines the county, zip code, and a close approximation of the address's actual lat/long coordinates. This is the same method used by popular applications such as Google Maps.

Not all addresses can be geocoded due to various factors. For those addresses, we use a ZipCode geographic database which assigns the general lat/long coordinates of the Zip Code listed in the FCC record. This method is less accurate because some zip codes cross county lines, and, because there is only one location for the entire zip code area, which might be quite large. Another accuracy factor is that the zip codes listed for some licenses is simply incorrect, due to mistakes made on the application, or, in one of the license processing steps. There are some zip codes which for unknown reasons, are unlisted.

QRZ always allows the user to input a custom lat/long position. If a user wishes to suppress their location, they can enter an arbitrary position, or, Latitude 0,0, Longitude 0.0..

About Grid Squares

By default, grid squares shown are determined directly from the lat/lon coordinates. Grid squares do not lie. There is only one grid square possible for any given lat/long position that doesn't lie exactly on a boundary line. As with the lat/long coordinates, you can enter an arbitrary grid square for your callsign. The system may, however, point this out to visitors of your page.

How to input new Coordinates

Lat/long coordinates must be entered in decimal degrees. Using this sytem, positive lattitudes are in the northern hemisphere and negative ones represent the south. Likewise, east longitude values are positive and west longitude positions are represented by negative numbers.

If you know your position only by the older degrees, minutes and seconds (nnn, nn', nn'' NE/SW) method, then you must convert these values to decimal values. An easy way to do this is to simply find your location on our online GridFinder application.


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