OS GPS Convertor
Introduction

This Pocket PC program converts positions between WGS84 latitude & longitude and Ordnance Survey (OS) British & Irish or Universal Transverse Mercator (UTM) worldwide grid references. It displays positions in multiple formats.
It can be used with:
- TomTom Navigator - to create a Point of Interest (POI) or Itinerary file ... then show on map, navigate to, etc.
- Destinator - to create a Favorite file ... then show on map, navigate to, etc.
- OziExplorer CE - to show the position on a map ... then create a waypoint, go to, etc.
TomTom is a registered trademark of and TomTom Navigator software is copyright TomTom BV, The Netherlands. OziExplorerCE is copyright D and L software, Australia. Destinator is a registered trademark of and Destinator software is copyright Homeland Security Technology Corporation (HTSC) and its successors and assigns.
License
This program is copyright (c) 2006 Barry Davies. You are hereby granted a free license to download the program for your own personal use. You may not modify or redistribute the program in any way. The program is provided "as is" without warranty of any kind, either expressed or implied. The entire risk as to the quality and performance of the program is with you. Should the program prove defective, you assume the cost of all necessary servicing, repair or correction. In no event will the copyright holder be liable to you for any damages arising out of the use or inability to use the program.
Setup
There's no install package. I've given detailed instructions below, with notes to help where your Pocket PC may be different to mine (an HP Ipaq 2210 running Windows Mobile 2003).
- Click this link and select to save the file to your PC: OSGPS-2-2-0.zip
- Extract the ZIP file contents. You should now have these files on your PC:
\OS GPS Convertor.exe
\TomTom\osgps.bmp
\TomTom\osgps.ov2
\TomTom\OS GPS Convertor.bmp
\TomTom\OS GPS Convertor.cap
\Destinator\osgps.bmp - Copy OS GPS Convertor.exe from the PC to any folder on the Pocket PC, in main memory or a storage card
- Create an OS GPS Convertor shortcut in the \Windows\Start Menu\Programs
folder on the Pocket PC. This lets you run it from the Start menu as: Programs - OS GPS Convertor
How? In Windows Explorer on the PC: Display the folder containing OS GPS Convertor.exe on the Pocket PC, then right-click on OS GPS Convertor.exe and select Copy. Display the \Windows\Start Menu\Programs folder on the Pocket PC, then right-click in it and select Paste Shortcut. Right-click on the new shortcut, select Rename, then edit the shortcut name to: OS GPS Convertor - Optional: You may want to add OS GPS Convertor directly to the Start menu
How? On the Pocket PC: Select Start - Settings - Menus. Scroll down the list and tick OS GPS Convertor, then tap OK
There are more steps later to set it up for the software you'll be using with it. But now is a good time to check that it works on your Pocket PC and try it out for the first time.
Basic use
To enter and convert positions:
- Select Start - Programs - OS GPS Convertor (or Start - OS GPS Convertor if applicable)
- Leave Grid set to British National Grid
- Leave Format set to 1: OS Grid Reference
- For Grid Ref, tap the ... button, tap TQ on the grid to select it, then tap OK
- Back in the Grid Ref text box, after TQ type the digits 300805
- Tap Convert
- The position entered is displayed in two OS grid formats, and the position converted to WGS84 in three latitude and longitude formats
- Tap New Position then repeat steps 2 to 7 using different input formats
- Tap Exit to finish. (Don't try the other buttons yet, they won't work!)
- Start the program again. Note that it remembers the last position entered
The next section gives more details of how to enter positions in each format. If you know all about that, move straight on to the following sections that describe how to use OS GPS Convertor with other programs.
Position formats
This section describes the formats that you can use to input a position.
Ordnance Survey grid references
National Grid references
National Grid references start with a two-letter code (British Grid) or one-letter code (Irish Grid) indicating a 100km x 100km grid square. This is followed by the Easting and Northing distance into that square from the South West corner. The fewer digits you use, the more approximate the reference. For example, 5-digit values (e.g. SD 12345 12345) are accurate to 1m, while the more common 3-digit values (e.g. SD 123 123, which is taken to mean SD 12300 12300) only indicate a position to within 100m.

- In Grid select British or Irish National Grid
- In Format select 1: OS - Grid Reference
- In Grid Ref type the grid square code then the Easting and Northing values as 2,3,4 or 5 digits each. The ... button lets you select the code from a grid diagram.
Note: Easting and Northing values must both be the same level of accuracy. Any spaces, punctuation or other characters entered are ignored, which can be helpful if you input values using handwriting recognition.
Full Easting and Northing values
Some OS maps such as the 1:25,000 Explorer range show the full Easting and Northing values along their edges, so you may prefer to enter positions in this format.

- In Grid select British or Irish National Grid
- In Format select 2: OS - Easting/Northing
- In Easting enter the Easting value
- In Northing enter the Northing value
Note: Always enter the full values for Easting and Northing, which are most often 6 digits long.
Ordnance Survey web site
For more information, see http://www.ordnancesurvey.co.uk/ Some very helpful PDF leaflets about map reading can be downloaded from: http://www.ordnancesurvey.co.uk/oswebsite/mapshop/
WGS84 latitude & longitude
The World Geodetic System 1984 (WGS84) is the reference system used by the Global Positioning System (GPS). OS GPS Convertor lets you input positions as a WGS84 latitude and longitude in any of the three formats commonly used. When you tap the Convert button, the position entered is shown in all three latitude & longitude formats, and the position is converted to whichever grid is selected in the Grid list.
Degrees (D.D)

- In Grid select any grid as required
- In Format select 3: WGS84 - D.D
- In Latitude select North ( + ) or South ( - )
- Type the degrees 0 to 90.000000
- In Longitude select East ( + ) or West ( - )
- Type the degrees 0 to 180.000000
Note: Zero values can be left blank. Don't type + or - signs, use the drop-down lists.
Degrees and minutes (D M.M)

- In Grid select any grid as required
- In Format select 4: WGS84 - D M.M
- In Latitude select North ( + ) or South ( - )
- Type the degrees 0 to 90
- Type the minutes 0 to 59.9999
- In Longitude select East ( + ) or West ( - )
- Type the degrees 0 to 180
- Type the minutes 0 to 59.9999
Note: Zero values can be left blank. Don't type + or - signs, use the drop-down lists.
Degrees, minutes and seconds (D M S.S)

- In Grid select any grid as required
- In Format select 5: WGS84 - D M S.S
- In Latitude select North ( + ) or South ( - )
- Type the degrees 0 to 90
- Type the minutes 0 to 59
- Type the seconds 0 to 59.9
- In Longitude select East ( + ) or West ( - )
- Type the degrees 0 to 180
- Type the minutes 0 to 59
- Type the seconds 0 to 59.9
Note: Zero values can be left blank. Don't type + or - signs, use the drop-down lists.
UTM Grid References
UTM Grid
OS GPS Convertor can handle UTM grid references (in the WGS84 datum) for any longitude worldwide and for latitudes from South 80 degrees to North 84 degrees. It cannot handle the two special zones for the polar regions.
UTM grid references (e.g. 30U 543210 5678900) consist of:
- Zone Number from 1 to 60 indicating the longitude zone.
- Zone Letter from C to X (excluding I and O which are not used) indicating the latitude zone. For calculation purposes it only matters whether the position is in the Northern or Southern hemisphere, and the zone letter isn't always provided in the grid reference, so OS GPS Convertor only requires the hemisphere which can be guessed if the code is not known.
- Easting value indicating the Easting in metres, optionally followed by the letter E.
- Northing value indicating the Northing in metres, optionally followed by the letter N.
For more information on UTM grid references, see http://www.dmap.co.uk/utmworld.htm or http://geology.isu.edu/geostac/Field_Exercise/topomaps/utm.htm or google for UTM.
UTM Grid reference

- In Grid select UTM grid
- In Format select 1: WGS84 - UTM Grid
- In Zone type the longitude zone from 1 to 60
- In Zone select the latitude hemisphere (latitude zones C to M are in the Southern hemisphere, and N to X in the Northern)
- In Easting type the Easting in metres
- In Northing type the Northing in metres
Note: Format option 2: WGS84 - UTM Grid is identical to option 1 at this release.
TomTom Navigator
Introduction
OS GPS Convertor can work with TomTom in two ways:
- Point of Interest (POI) file. This is a quick way to input a position, typically while TomTom is running, then display it on the map, navigate to it, etc. The POI file only ever contains one POI, which is moved to the position you input each time
- Itinerary file. This is a way to prepare a list of positions for later use. The list might be a series of "drive by" waypoints that forces TomTom route planning to take your preferred route, or a series of "destination" waypoints that you want to visit one by one, or a mix of both. After creating the itinerary file, you can load and use it in TomTom when needed

The animation to the right shows how well the two programs can be integrated.
OS GPS Convertor is used to enter a map grid reference, then TomTom is used to check the position and navigate there:
- Tap the screen
- Start OS GPS Convertor
- Enter the position and convert it
- Create the POI. This exits back to TomTom and displays the position on the map
- Check the position on the TomTom map and adjust it if necessary
- Start navigating to the position
TomTom Navigator Setup
The following notes show how to set up the two programs to work together.
Starting OS GPS Convertor from TomTom
It can be hard to start other programs when TomTom is running. These are some options:
- If you are using TomTom version 3 it's not a problem. You can display the Start menu by tapping twice in the top left hand corner of the screen when in Navigator view, and then run OS GPS Convertor from there
- Use a hardware button. It makes more sense to assign the button to display the Today screen or the Start
menu rather than just to run my program, but the choice is yours.
How? I set up the hardware buttons on my Pocket PC by selecting Start - Settings on the menu, then tapping the Buttons icon - Use a TomTom custom menu. This is my preferred option, but this subject fills whole web pages by itself.
Google for TomTom.mnu or look on the PocketGPSWorld TomTom Navigator forum to find out more details.
How? You will need to create a TomTom.mnu file in the \TomTom\SdkRegistry folder on the Pocket PC. This file defines all the entries for your menu. The entry for OS GPS Convertor will look like this (the final digit after SDK may be different, depending on what else you've got installed.):
MENUITEM|TASK_SDK1|
You will also need to create OS GPS Convertor.cap and OS GPS Convertor.bmp files in the same folder. Example files are included in the zip file you downloaded (they unzip to the \TomTom folder on your PC). The .bmp can be copied across as is. The .cap file will need editing first in a text editor, to amend the AppPath line to the folder on your Pocket PC where OS GPS Convertor.exe is installed. The path goes between the two || characters, so if you created \CF Card\Utils\OS GPS Convertor.exe then you would put:
AppPath|\CF Card\Utils|
OS GPS Convertor settings
- Copy the osgps.ov2 and osgps.bmp files (that were unzipped to the \TomTom subfolder on the PC)
to the TomTom map folder on the Pocket PC
Where are map files stored ? On storage cards, with folder names ending in Map. For example, my TomTom 3 GB map was in \CF Card\Great_Britain Navigator Map, while my TomTom 5 GB Plus map is in \CF Card\Great_Britain_Plus-Map - Start OS GPS Convertor
- On its menu select Settings - TomTom
- Tick Show position on TomTom map only if you are using TomTom version 5 or later and you want the POI position to be displayed automatically on the TomTom map after it is created. Leave it blank otherwise
- In POI / Map folder type the full TomTom map folder name.
On some Pocket PCs you can fill this in by tapping Browse - if you now see a list of POI files,
simply tap on any POI in the required map folder to fill in the folder name.
Example: I have this field set to: \CF Card\Great_Britain_Plus-Map - In ITN file format select the TomTom version you are using
- In ITN folder type the full TomTom itinerary folder name.
Example: TomTom 3.07 put mine in the \My Documents\TomTom Navigator Settings folder in main memory. TomTom 5 puts them in the \itn folder in main memory. If in doubt, create an itinerary in TomTom and save it, then look for the folder containing that .itn file! - Tap OK to save the settings
- If you ticked the option to show the POI position on the TomTom map, create the following folder on your Pocket PC
if it doesn't already exist:
\TomTom\SdkFileCalls
Note that this is the folder path from the root of the Pocket PC. It is not the \tomtom folder in \My Documents (which, confusingly, is shown first as just \tomtom when I look at the Pocket PC from Windows Explorer on my PC). Look carefully to find the correct folder. Depending on what other add-ins you've already installed, the \TomTom folder may already have the \SdkFileCalls subfolder in it, or another one called \SdkRegistry
TomTom settings
You can choose whether or not TomTom displays the OSGPS POI symbol on its map. It's usually helpful to display it, but some users have better performance when custom POIs are not displayed.
To display (or hide) the OSGPS POI in TomTom version 3:
- Start TomTom and display its menu
- Select More - More - Properties, then the POI tab
- Scroll to OSGPS in the list and tick (or clear) its box
To display (or hide) the OSGPS POI in TomTom version 5:
- Start TomTom and display its menu
- Select Change Preferences - > - Manage POI - Enable/Disable POI
- Scroll to OSGPS in the list and tick (or clear) its box
Using with TomTom Navigator
Create a POI and navigate to it
This is the quick way to navigate to a position. Each time you do it, the new POI position overwrites the existing one.
- While using TomTom, start OS GPS Convertor
- Enter a position and tap Convert
- Tap TomTom POI. The POI file is updated and OS GPS Convertor exits
- If you use the 'Show position on TomTom map' setting, the position is displayed on the map:
- Drag the map if necessary to adjust the position
- Tap the cursor button at the bottom of the screen
- Select Navigate there
- If you don't use that setting, you are back in TomTom where you left it:
- Display the TomTom menu
- Select Navigate To - Point of Interest - OSGPS
- [TomTom 3] The POI is selected so just tap OK
or
[TomTom 5] Tap the POI to select it, then tap the Done button
Note At step 3 you may see the message "Error code 11 - sharing error." This indicates that TomTom has locked the POI file because it is using it, so my program cannot update the POI position in the file. One example of when it happens is if you ask TomTom to navigate to the POI when it has no satellite fix. It's also been suggested that it is more likely to occur if the POI is displayed on the map, but I've not seen that yet. The only solution so far found is to exit TomTom to remove the lock, then start again. You may be able to just ask it to navigate to somewhere else, but on my Pocket PC that doesn't seem to release the lock. You may also like to experiment with not displaying the POI on the map, if you get the problem a lot.
Create an Itinerary and use it
This is a way to build a list of positions to work with in TomTom. OS GPS Convertor only works with its own itinerary file called osgps.itn to avoid overwriting any of your data. If you want to create several itinerary files with it, create one then rename the file, create the next and rename it, and so on.
To create the itinerary in OS GPS Convertor:
- Start OS GPS Convertor
- Enter a position and tap Convert
- Tap the TomTom Itinerary button
- In the dialog box, select your options then tap OK
- A drive-by waypoint forces TomTom to plan its route through this point. When you are navigating, TomTom just shows it as a flag and drives you straight through it
- A destination waypoint is one that TomTom will plan a route to. When you are navigating, TomTom shows the distance and time left to go to this destination and when you reach it you have "arrived".
- The waypoint is given a default name, that you can edit if required
- You can choose either to add this waypoint to the end of the current itinerary file, or to create a new itinerary file (overwriting any existing one) starting with this waypoint
- To add another position, tap New Position then repeat steps 2-4
- To finish, tap Exit
To use the itinerary in TomTom version 3:
- In Itinerary view, tap & hold on the itinerary list until a menu pops up
- Select Load...
- Tap on OSGPS
- You can now either start navigating to the first destination in the itinerary, or work with individual positions in the itinerary as follows:
- Tap & hold on an itinerary position until a menu pops up
- Select More ...
- Select an action from the menu
To use the itinerary in TomTom version 5:
- Display the TomTom menu
- Select Itinerary planning
- Select Options - Load Itinerary - Yes - osgps
- You can now either start navigating to the first destination in the itinerary, or work with individual positions in the itinerary as follows:
- Tap on an itinerary position
- Select an action from the menu
OziExplorer
Introduction
OS GPS Convertor works with OziExplorer by showing the position entered on the OziExplorer map. It starts OziExplorer for you if it is not already running. You can then use it in OziExplorer, for example creating a waypoint then navigating to it.
OziExplorer setup
OS GPS Convertor settings
To set up OS GPS Convertor to work with OziExplorer:
- Start OS GPS Convertor
- On its menu select Settings - OziExplorer
- In OziExplorer program folder type the full folder path to the OziExplorer program
By default it is the \OziExplorer folder in main memory. If you installed OziExplorer to a memory card the folder path will be different - Set OziExplorer program file to the version of OziExplorer that you use
OziExplorerCE.exe is the standard program, OziCE_Dev.exe is the development version - Tap OK to save the settings
Using with OziExplorer
Show position on map and create waypoint
To show a position on the OziExplorer map then create a waypoint at it:
- Start OS GPS Convertor
- Enter a position and tap Convert
- Tap the OziExplorer button
- The position is displayed on the OziExplorer map
- On the OziExplorer menu select File - Waypoints - Create Wp at Position
Note: The map will not move to the position entered if OziExplorer is already running in moving map mode.
Destinator
Introduction
OS GPS Convertor works with Destinator by creating a Favorite file with the position entered. The Favorite Item has the WGS84 latitude and longitude coordinates as its name, and the OS or UTM grid reference as its description. The OSGPS Favorite file only ever contains one Item, which is overwritten with the new Item each time you use this feature.
Destinator setup
OS GPS Convertor settings
Set up OS GPS Convertor to create a Destinator favorite:
- Copy the osgps.bmp file (that was unzipped to the \Destinator subfolder on the PC)
to the Destinator favorites folder on the Pocket PC.
Where are favorite files stored ? In the folder structure where you installed Destinator. A default installation of Destinator 3 puts them in main memory in \DestinatorApps\Destinator\Common\Favorites - Start OS GPS Convertor
- On its menu select Settings - Destinator
- In the Destinator Favorites folder type the full Destinator favorites folder path
- Tap OK to save the setting
Using with Destinator
Create a Favorite Item and navigate to it
This is a quick way to navigate to a position. Each time you do it, the new Favorite Item overwrites the existing one.
- From Destinator, return to the Today screen
- Start OS GPS Convertor
- Enter a position and tap Convert
- Tap Destinator Favorite. The Favorite Item is created and OS GPS Convertor exits
- Back in Destinator, select Destinate - Favorites - OSGPS - Items
- The only entry is selected, so just tap Navigate
Note At step 6 you can select Tools instead, if you want to modify the Favorite Item, copy it to another category, etc.
Reference
Program support
You'll find me in the Pocket GPS World forums, where my username is barryd. I don't use Destinator, so any questions about how to use it with my program are better put to username Getoffandwalk, who worked out how to do it.
You will also find me in the Groundspeak Geocaching forums, mainly in the UK forum, where my family's username is BandMandAandA.
Program history
Version 1
- 1.0.0, 02 Aug 2004 - Original release.
- 1.0.1, 11 Aug 2004 - Two minor bugs fixed
Lat/Long layout (previously Long/Lat)
Format retained between uses. - 1.1.0, 28 Oct 2004 - Irish National Grid added
Partial Easting/Northing can be entered
Grid, format and last position retained between uses. - 1.2.0, 13 Feb 2005 - OziExplorerCE support added
No longer need to put its shortcut on Start menu
Now brings TomTom or OziExplorerCE window to the front
Bug fixed in latitude/longitude storage between uses. - 1.2.1, 27 Mar 2005 - Bugs fixed affecting rounding and display of some results
(less than 1%)
Improved accuracy of Irish National Grid conversions.
Version 2
- 2.0.0, 03 Jun 2005 - Redesign to extend functionality and support TomTom
Navigator 5 (which no longer has a Go to coordinates screen).
Older TomTom versions still supported. - 2.0.1, 12 Jun 2005 - Fixed bugs to make it work properly with TomTom Navigator 5
Added more control over positions created in itinerary
Added option to specify where OziExplorer is installed. - 2.1.0, 03 Jul 2005 - Destinator support added
OS grid keyboards added
TomTom Itinerary entry name now editable
Select which version of OziExplorer to run
Tidied up Settings dialogs and registry settings
Various minor bugs fixed. - 2.2.0, 05 Aug 2006 - Settings are now being saved for Windows Mobile 5 users.
Added UTM grid references as a new format
Added option to show POI position automatically on TomTom map on exit
Added notes on setting up an entry for OS GPS Convertor on a TomTom custom menu
Credits
A big thank you to all those people who have given me ideas and support in developing and testing this little program.
