New and improved Maidenhead Grid Square Locator
May 30th, 2009 by K2DSL

I have mentioned a few times (most recently at Find that maidenhead grid locator for an address)  about Maidenhead Grid Square Locators and my desire to have them as part of the log for each contact. It helps show distance as well as for mapping and just overall complete information on a contact.

The QRZ.com page that allows you to enter an address and calculate a grid locator hasn’t worked for half a year despite multiple requests to have someone look into it. Someone recently suggested using APRS.fi to do it and that works fine. But in the end I decided to write my own, which probably took more time to find the right formulas to convert between lat/long and the grid square then to code the actual page.

At http://www.levinecentral.com/ham/grid_square.php is the web page I put together. You can enter in an address or a call sign. If a call sign is entered, I pull address info from QRZ.com and the process continues from there. The address is then processed by Google and it comes back with either a latitude/longitude for that address or that it didn’t find anything. If Google doesn’t find a hit, I start stripping the address down piece by piece and try again.

Once a hit is found I calculate the grid square based on the latitude and longitude returned by Google. I place a map point at that location (usually the location specified or associate to the call sign) with the info as well as the grid location displayed at the top of the page for quick reference. If the address was manipulated, the address which returned results is displayed. I then can calculate one of the corner points for the maidenhead grid square locator border and draw a rectangle that represents the area for the grid square the location is within.

There is nothing very magical about the page but I wanted something to do what I needed and how I wanted it done so what better way to get that then writing it yourself! The current Google mapping framework I use is the same as used by the Repeater Mapping pages which is great for getting something built quickly. Depending on how much more I might want to add to this page, I might need to use a different Google toolset or deal with the Google API directly.

I’ve looked and looked at the terms of use for the QRZ lookup which is using my paid account. I can’t find anything that seems to disallow what I’m doing posted on the web site or distributed to me when I signed up.  Hopefully it is ok. Please let me know how you like it. I know for me and finding grid square locators for call signs/addresses that QRZ doesn’t already have, it will save me a lot of time.

73,
K2DSL

Posted in Misc

6 Comments

Posted By: David, K2DBK on June 1st, 2009at 11:16 am

Really nice job David. One nice feature that you didn’t explicitly mention is that since it’s powered by Google Maps, you can put in a location, like a state park, where you might be operating from without having to find the actual address. One suggestion: If you could add in a feature to allow entry of a 4 or 6 character grid square it would have pretty much everything. I have a grid square locator on my k2dbk.com website that does just that, but I like yours better anyway.

73,
David, K2DBK

Posted By: David - K2DSL on June 4th, 2009at 8:00 pm

I added the ability to specify a grid square (4 or 6 characters) and plot that. I also added some additional info and link the call sign displayed to QRZ. I threw in a clear button to clear the form.

If an address it entered, it maps that. If no address and a call sign is entered, it maps that. If only a grid square is entered it plots that.

Posted By: Scott N3SW on September 29th, 2009at 2:02 pm

Thanks for the Maidenhead locator site. One suggestion, can it be enhanced to handle locators of more than 6 characters? If I have a device that gives me an 8 character locator, can you narrow it down more on your mapping function?
73
-sw-

Posted By: WE7X-Rod on October 5th, 2010at 8:13 pm

Great job! I like it a lot.
Is there a way to find a location on the map, and get the resulting 6-digit grid easily?
It might be there alraed. If so, I have apparently missed it.
Thanks,
Rod
Issaquah, WA

Posted By: K2DSL on October 6th, 2010at 7:02 am

Rod – Thanks for the comment. If you are asking if there’s a way to click on the map and get the grid square, then no. You can type in a location in the top address field and that will find the location and show the grid for it. If you want to pan/scan the map and then click on it to get the grid, I’d suggest checking out http://no.nonsense.ee/qthmap/ or http://f6fvy.free.fr/qthLocator/fullScreen.php

Posted By: N3TUI Tom on May 8th, 2012at 10:06 pm

Hello Dave
First time I have come across a site that depicts my actual as close as it appears on Google maps. Very close to actual. Koodoos to ya.
73
Tom
N3TUI

Post a Comment Below »
Your Name:

Your Email:

Website?

Your Comment:

Please note: Comment moderation is enabled and may delay your comment. There is no need to resubmit your comment.

Private