Letterboxing OS Grid to GPS Software

General letterboxing discussion.

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Colin
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Letterboxing OS Grid to GPS Software

Post by Colin »

Hi
I have written a small program which some people may find useful :!: If you subscribe to the Letterboxing Catalogue (Written by Mike Holiday) and use a GPS along with a compass!!! Basically the program extracts all the clues with valid grid refs from the Letterboxing Cats DB and converts the cords from OS Grid to WGS84 (GPS) format you can then filter by grid squares and various other things, if you have a Garmin GPS you can then send the Cords and Clues directly to it, or you can create a GPX file instead if you wish to import to your GPS via another application.
Currently it is still A WIP and I am ironing out some minor bugs.
Anyway if you want to download it feel free the URL is http://www.gpsletterboxing.talktalk.net/

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Post by Dizzy »

An excellent program Colin, however I'm experiencing problems with an error report whilst attempting to upload the system DB file STAMPS.SBF. Please see the screen shots below.

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Post by Colin »

Hi Dizzy
currently it only opens and convert stamps.sbf (this contains the list of all the current an old leterboxes) and the places.sbf (contains a list of various places around dartmoor). judging by your sceen shot you are trying to open the walks.sbf file? I am not sure what your copy of this file of this file contains ? I presume it must be info you have added yourself?

My copy has nothing it it so I have not tried to convert it however if you zip your copy up and email it to me I will have a look to see if there is any info in there worth converting.

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Post by Dizzy »

Hi Colin, the walk.sbf was just one of the files I tried to upload but I do understand that your program works only with the stamps.sbf and the places.sbf. I can open the places.sbf without any problems, however our stamps.sbf contains nearly 5000 clues so maybe it's just the size of the database I am attempting to upload.
If the filepath is not c:LETTERBOX/STAMPS.SBF more so extracting this froma letterboxing stamps.sbf from a saved file on a memory stick should work just as well hopefully.
Thanks for the offer of taking a look at the file Colin but this is only the letterboxing database, plus don't take this the wrong way but I would prefer to not pass on nearly 5000 hand typed clues by my partner. :lol:
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Post by Colin »

Hi Dizzy
First off I am impressed someone has entered 5000 clues manually now that is impressive. One of the main reasons I wrote this app is so I did not have to manually transfer clues from the DB to my GPS. Also it does not matter where the file resides.

I don't think it is the amount of records, the current stamps.sbf contains over 22000 stamps, as it also holds all the old ones as well as the current ones. Can you post a screen shot of the dialog you actually get when trying to open the stamps.sbf file as I can possibly work out at which point it is failing the opening? Trying to reading in a DB file in Biary format is a bit on the tricky side and I may have missed something somewhere and I can probably add some extra code to trap the error and ignore it. It may be an issue with trying to resable the database records in the correct order?

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Post by Dizzy »

Hi Colin, I can't quiet see where you mean about the dialogue info, all I can really show you are the screen shots from start to finish while attaching the DB file extension. If there's anything I've missed then please let me know.
Oh, BTW I've just been corrected by my partner Crafty Jo that she has now typed out nearly 10,000 clues onto the letterboxing database!!! Now that's some going don't you think! :) This one is an old copy to try out your program.

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Post by Colin »

Hi Dizzy
10,000 clues sounds like you are a slave driver :)
A quick question I notice that your file only contains 51000 datablocks so I preume you must of started with an empty file as the current stamps.sbf file contains 81000 or so blocks? which is about 22000 records. Also I notice from one of your screen shots that you have lots of SBF files in your folder are these just old backups ? if so can you try the oldest one to see what happens.

What I can do is do to get to the bottom of this is to do a mod on the import routine which will write each record read back out to a text file so I will then be able to see the exact record that generates the error

if that is ok with you

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Post by Dizzy »

Thanks Colin, yes the other DB files are different database folders contains clues from other letterboxers which I have also tried to open without success.
If you can write an Mod to see if you can locate my problem that would be great. If it is my error then please accept my apologies, if not then if a downloadable Mod for your program could be available that would be great!

Thanks again,

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Post by Colin »

Hi Dizzy have PMd you with an update

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Post by Nik - KOTM »

there's an update?
Cos this looks interesting
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Re: Letterboxing OS Grid to GPS Software

Post by Gemma »

Colin wrote:Hi
I have written a small program which some people may find useful :!: If you subscribe to the Letterboxing Catalogue (Written by Mike Holiday) and use a GPS along with a compass!!! Basically the program extracts all the clues with valid grid refs from the Letterboxing Cats DB and converts the cords from OS Grid to WGS84 (GPS) format you can then filter by grid squares and various other things, if you have a Garmin GPS you can then send the Cords and Clues directly to it, or you can create a GPX file instead if you wish to import to your GPS via another application.
Currently it is still A WIP and I am ironing out some minor bugs.
Anyway if you want to download it feel free the URL is http://www.gpsletterboxing.talktalk.net/

Colin
Colin,
Very good apps, but why would one want to convert OS to WGS84? My GPS, like most I guess, deals with OS. Letterboxes are findable by OS.

Will try the apps though.
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Post by Sowerby Streaker »

Looks a very impressive piece of work Colin -
O.K. Just tried to run the program, loaded O.K. then when I went to upload STAMPS I got a message which said ' Bugger something done wrong' Rather strange message, so is this program safe, or am I doing something wrong :(

Just got a bit further and it started to load then up came the same message that Dizzy had 'Access violation at address ....'
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Post by Colin »

Hi Gemma
in reply to your question the idea is not to have to retype the clues but to be able to export them to either a GPX file or directly to a GPS from the letterboxing system. For example if you use the letterboxing system software you have to reneter the Grid Refs decriptions either directly into your GPS or in a program such as Mapsource / Memory maps Etc to send data to your GPS. If for example you use map source you would enter the OS grid refs / Decription, map source then does a Helmert transform to convert it to WGS84 format and then sends it to your GPS. If you enter the OS grid directly into your GPS the GPS does the same conversion in memory. No GPS unit can you the OS grid directly as the GPS sats are configured to send WGS84 positioning data. Thw whole idea is to cut out the retyping of clues. I hope this explains everything.

Hi Sowerby Streaker
The Bugger something went wrong it just my sense of humour when an error occurs, (it won't damage anything) I think I have tracked down the issue? It is hopefully to do with the Number of Records in the stamps.SBF file being incorrect, it seems that if a person adds there own clues to the letterboxing system the Record counter in the file is not always incremented even though there are new records. (Its not the letterboxing sytem it is an issue with superbase) my app took this number and created an array (spreadsheet) in the memory sized according to the file header number of records, the issue is that there are more records than the array is sized for so it overwrites the end of the array causing the error.

Hopefully I have fixed this, It needs a bit of testing but once done I will update you.

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Post by Sowerby Streaker »

Colin wrote:Hi Gemma
No GPS unit can you the OS grid directly as the GPS sats are configured to send WGS84 positioning data.
Hi Sowerby Streaker
Hopefully I have fixed this, It needs a bit of testing but once done I will update you.
Thanks for swift reply - thank goodness it was your sense of humour :roll: Appreciate the effort you are making as well - must be very time consuming, but a challenge :wink:

Re your answer to Gemma - I can manually put in the 10fig grid into my GPS directly e.g SX 12345 BNG 12345 so exporting straight from a file would be great. I can export from map to GPS once I have plotted my route onto Tracklogs, but not export from the letterboxing program.
Youv'e certainly got a few of us 'hooked'
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Post by Colin »

Hi Sowerby Streaker its taken a fair few hours so far but am on the home stretch now once this import bug has been soterd. I am sure there are a few other minor issues (I know of one to do with redrawing the grid everytime the height is updated) but the file import is the only tricky one to fix.
I am not sure if you have tried but you should be able to open the places.sbf file and also the export.sbf (update file). Once these few issues are sorted I am debating trying to add drawing of tracks so the clues / tracks can be exported in one go. Currently If you want to add tracks you will have to export the clues as a GPX file and then import them into your mapping program and then add the tracks.
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