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cattivikkio

Editing list of preloaded geocaches

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Hello,

 

I recently bought a Garmin GPSmap 64st, which came preloaded with 250,000 geocaches.

The list contains many of the caches I have already logged, plus many more in countries which I am not planning to visit in the foreseeable future.

On the other hand I think it's cool to have preloaded caches, as long as they're in my area and I haven't logged them.

So, I would like to be able to edit the list (via a script which I will write) and remove all the caches that I'm not interested in.

 

The problem I'm having is of course that the preloaded caches do not come in a GPX file but rather in a GGZ.

More precisely they are in the file preload.ggz, along with preload.sum and preload.ver, under the GGZ folder.

I've done some reverse engineering and found out that the preload.ggz is simply a zipped file which contains both the caches (as a bunch of PQ's) and a SQLite3 database used to access the caches on the device.

 

I know I can figure out how to remove the caches and update the database, but I was wondering about the preload.sum file: I'm pretty sure this is some kind of checksum, so I assume if I modify the db I would also have to ricreate the checksum file.

 

Does anyone have any idea on how this checksum (if it is indeed a checksum) is calculated? It is a 4 bytes file, so it's not an md5 for sure.

 

Thanks in advance

/cattivikkio

Edited by cattivikkio

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First find that file and delete it. It is absolutely useless. New caches in the area you want are being placed and some of the ones in the file are out dated, disabled or even archived. The shelf life of a file is not that long.

 

Then go to the Pocket Query page and set up a PQ or two to get current information and load that. You can even set it up to run once a week to keep your device up to date.

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First find that file and delete it. It is absolutely useless. New caches in the area you want are being placed and some of the ones in the file are out dated, disabled or even archived. The shelf life of a file is not that long.

 

Then go to the Pocket Query page and set up a PQ or two to get current information and load that. You can even set it up to run once a week to keep your device up to date.

 

+1

 

B.

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First find that file and delete it. It is absolutely useless. New caches in the area you want are being placed and some of the ones in the file are out dated, disabled or even archived. The shelf life of a file is not that long.

 

Then go to the Pocket Query page and set up a PQ or two to get current information and load that. You can even set it up to run once a week to keep your device up to date.

+2

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First find that file and delete it. It is absolutely useless. New caches in the area you want are being placed and some of the ones in the file are out dated, disabled or even archived. The shelf life of a file is not that long.

 

Then go to the Pocket Query page and set up a PQ or two to get current information and load that. You can even set it up to run once a week to keep your device up to date.

 

What an easy solution! Even easier, why don't I just throw away my GPS? So I don't even need to bother removing the file. Problem solved! :lol:

 

Seriously, I appreciate the time you took to answer but I had read the posts about how to delete the file. If I wanted to do that, I wouldn't have bothered posting under a new title "Editing...."

 

I understand that the file gets obsolete with time, still with 250,000 caches there's a very high chance that when I'm in some area and I see a cache on my GPS, that cache is still there. If it's not, then I only wasted a few minutes searching, no big deal. It's a bit worse if I spend time re-logging a cache that I had logged and forgot about...

Having so many preloaded caches is good for those occasions when I have my GPS with me even if I hadn't planned to be geocaching in that area and therefore had not loaded any PQ.

 

So, just to make it clear and save everybody's time: I know how to delete the file. I'm asking for someone who knows how to edit it or rather (since i know how to edit it), how to recreate the checksum (assuming that's what it is)

 

TIA

Edited by cattivikkio

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I still say delete it, and start afreash...

 

Otherwise, if you insist on keeping the file, load it into GSAK, do a cache re-freash, and delete the Found, and Archived caches, maybe even down load newer caches from a PQ, then reload to the GPS.

 

In a new area, even 5 minutes looking for a cache that is long gone, when you could have found another cache that IS there, would annoy me!

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But the point is, if you're going to be in an area, run a quick pocket query before you go so that

 

1. your listings are fresh and you have the most recent logs to reference.

2. You have more listings in the area to choose from.

 

the pre-loaded geocaches sounds like a good idea. In practice, Garmin was just showing off its new .ggz file format that Groundspeak has yet to adopt. It won't surprise me if Garmin abandons this practice with all future models and instead returns to including a free month of premium membership with your purchase.

 

Actually, it wouldn't surprise me if the next round of the gpsMAP and eTrex series gets wifi and geocaching live built in as the Oregons did.

Edited by mineral2

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If you onsist. Ypu can edit it n Basecamp.

 

I'm pretty sure Basecamp will not read GGZ files.

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I still say delete it, and start a fresh...

 

Otherwise, if you insist on keeping the file, load it into GSAK, do a cache re-fresh, and delete the Found, and Archived caches, maybe even down load newer caches from a PQ, then reload to the GPS.

 

You could update found, but that is about it. The API only allows 10000 updates per day. You could filter and update ones in your area though.

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Load the 250k pre-load GGZ into GSAK, cross reference with your own 'found it' database, then update for archived listings, and export back to your GPSr.

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If you onsist. Ypu can edit it n Basecamp.

 

I'm pretty sure Basecamp will not read GGZ files.

You're right. I just assumed Garmin would support a file it created in its software.

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Load the 250k pre-load GGZ into GSAK, cross reference with your own 'found it' database, then update for archived listings, and export back to your GPSr.

 

This is the only way that I know of to edit the supplied GGZ file. The Garmin Export GSAK macro will export in GGZ format again. I did that myself when I first got my GPSMAP 64s. It was a long, tedious project. And like others here mentioned, many of the caches in the file were either disabled or archived. After playing around just to see what GGZ was all about, I deleted the file.

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I still say delete it, and start a fresh...

 

Otherwise, if you insist on keeping the file, load it into GSAK, do a cache re-fresh, and delete the Found, and Archived caches, maybe even down load newer caches from a PQ, then reload to the GPS.

 

You could update found, but that is about it. The API only allows 10000 updates per day. You could filter and update ones in your area though.

 

Run a 'Status Check' to identify Archived, Found and Temporary Disabled caches.

Then work on updating with 10,000 lite and 6,000 full calls on the API per day.

Edited by Bear and Ragged

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Run a 'Status Check' to identify Archived, Found and Temporary Disabled caches.

Then work on updating with 10,000 lite and 6,000 full calls on the API per day.

 

Is status check not limited to the number per day?

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@cattivikkio 

 

Did you try it? I was thinking the same as you -- be nice to have the pre-load updated for unplanned new areas, and have it refreshed/updated for archived/myfinds for local areas (or even just remove local areas entirely, use my PQs instead). I'd be interested in hearing what your results were.

 

Another alternative, that would work for me, if I could get it to work -- change out the icons on my PQs so at least where there is a PQ loaded I can distinguish between my PQ and the preloads. I haven't been able to get that to work either - or find a forum link.

 

Can anyone point me in the right direction?

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Hi, I know this is an old thread, but still high in Google searches related to GGZ file format.

 

Anyway, the four bytes in the .sum file aren’t checked by the GPS, so edit away! :D

 

Perhaps it is checked, along with the basemap & preloaded map .sum files when the device is started in test mode,

so Garmin service can tell the files are corrupt, and then rewrite them if that is the case.

 

 

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I'm not sure that Garmin still supports or develops its own GGZ file format. Basecamp neither reads or writes GGZ files, requiring you to use 3rd party software to create them. The new GPSs continue to support the format, but maybe because the OS/firmware is simply written from the previous generation of devices and it's likely no more trouble to leave GGZ support in than to take it out. That and the geocaching community still enjoys it.

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