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60CS memory management


norScot
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As I prepare for a 4-week trek in Nepal, I'm wondering if I have enough memory to record tracks for the whole trip. I don't have any maps installed, and will empty out all the waypoints and caches. I'm aware that I can set the frequency of recording track points, but I'd like to hear any other trips for optimising memory usage. I've heard that saving tracks is a bad idea, as each is allocated a fixed amount of memory, irrespective of length. Is this so? Should I never save enoute?

Is there any way that I can see how much memory has been used, and how much remains? I am definitely not carrying a laptop in my rucksack!

Thanks for any help.

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As I prepare for a 4-week trek in Nepal, I'm wondering if I have enough memory to record tracks for the whole trip. I don't have any maps installed, and will empty out all the waypoints and caches. I'm aware that I can set the frequency of recording track points, but I'd like to hear any other trips for optimising memory usage. I've heard that saving tracks is a bad idea, as each is allocated a fixed amount of memory, irrespective of length. Is this so? Should I never save enoute?

Is there any way that I can see how much memory has been used, and how much remains? I am definitely not carrying a laptop in my rucksack!

Thanks for any help.

 

I cannot comment on whether or not saving the track uses a fixed amount of memory. However, I do know that saving tracks causes some of the data such as speed for each segment to be lost.

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This is the dilemma I am in also. I have to save tracks here in Ecuador because I use those tracks to get back to places I visit regularly.

 

My eTrex Legend Cx is limited to 25 tracks and I am just about at that limit. I want to be able to use the memory card to store tracks. I can store custom POI's there - why not allow tracks as well.

 

Can anyone comment on this? Are we stuck with the hardware limit on the number of saved tracks?

 

What happens if I log a very long trip? There is some kind of data wrap function - will I actually lose track data after some number of data points? How does this work?

 

Thanks,

Joe

Quito, Ecuador

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This is the dilemma I am in also. I have to save tracks here in Ecuador because I use those tracks to get back to places I visit regularly.

 

My eTrex Legend Cx is limited to 25 tracks and I am just about at that limit. I want to be able to use the memory card to store tracks. I can store custom POI's there - why not allow tracks as well.

 

Can anyone comment on this? Are we stuck with the hardware limit on the number of saved tracks?

 

What happens if I log a very long trip? There is some kind of data wrap function - will I actually lose track data after some number of data points? How does this work?

 

Thanks,

Joe

Quito, Ecuador

 

Lets take these one at a time. The 60CS will save a fixed number of tracks (10 or 20, I cannot recall right now), each with 500 track points. It will save an active track log of up to 10,000 track points and will either wrap or stop when full depending on what you set it to do. This is regardless of the number of routes, waypoints or maps you may have saved.

 

The Legend Cx, I believe, will allow you to record your active log to the data card. It will record as much as you have space for on the card. You will have to upload them to a computer when you return from your trip. As far as what is saved in memory, you are subject to basically the same limitations as the 60CS.

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What I used to do with my old Garmin 12XL with it's limit of 1024 trackpoints before overwriting (and I see no reason why it wouldn't also work with the 60CS - it did with my old 76CS :anicute: ) was to download the tracklogs via a serial cable to my old Palm PDA which was running the GPilotS program.

 

GPilotS also can store all those waypoints in excess of the gps storage limit (500 or 1000) in the PDA and you can upload them to the gps as required.

 

If you want to go that way just make sure you use a 'serial' capable Palm. There are suppliers of the necessary gps to PDA cable - you need to get the one for your particular combo - or you could make up your own, as I did.

 

Unfortunately I can no longer do this with my new USB Palm Tungsten E2 as it doesn't have any hosting ability to accept serial input. :anicute:

 

But I now have no real need anyway as I now have a 76CSx and a 1gig microSD card and save the tracklog to the card. Someone mentioned somewhere else that saving trackpoints at 1 second intervals to a 1 gig card (2 gig cards are quite cheap at the moment) that it would take a couple of months to 'fill' the card with tracklogs. Of course, the amount of storage available for tracklogs would depend on what else is loaded on the card i.e. maps POI etc. I'm not sure how many bytes is used to store a single trackpoint but this should be easy to find out. Also waypoints in excess of the 1000 gps limit can be loaded as POI direct to the card so the waypoint storage is also virtually unlimited.

 

So the real solution to your problem would be to upgrade your gps to one of the latest models eg 60Cx, 60CSx, 76CSx. The tracklogs are stored as daily gpx files on the card.

 

Enjoy your trip.

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Even with a CS, you can influence how it saves the current track log. On the track log page, you can see how much of the current log space is used. When at 100%, it's full. Once there, it will loose the oldest points, or stop recording, depending upon the setting.

For the track log setting, use Automatic, then, if you are away from a computer a very long time, set the sampling frequency to something less than normal.

 

My 60 CSx can save 20 tracks, but then the resolution will be reduced. Saving to the card is a good idea in these units, but not available on the CS, of course.

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The problem with saving to the SD card is that, according to the manual, these are files that are NOT used by the unit, but are intended to be used by PC mapping programs.

 

I think what the OP and I are asking for is the ability to carry more routes in the unit that can be used at any time. I need them to get to and from places in a South American city that does not have basemaps available, nor does it have well-marked streets and highways. I get somewhere with someone who knows the way, track it, and use that to get home and back to the location another day.

 

The .gpx files stored on the SD card, according to the manual for the LegendCx, are stored in daily intervals. Does this mean that if I start and stop a track to be stored in the unit, that discrete track is stored in the daily file on the SD card, or is just a continuous track log for that date? That is not useful to me since I need discrete tracks to a location. I guess I should play with it some and find out.

 

I think it all boils down to us wanting more capacity in the unit, or the ability to write and read unit-usable tracks to the memory card. 25 tracks is just barely enough for me. 50 would be great.

 

Joe

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Hi Joe,

 

I misunderstood what you and norScot were wanting to do. Confusion between tracks and tracklogs. I now gather you want to store tracks (i.e. routes that you want to follow, possibly repeatedly) and not follow, or necessarily store, where you actually went previously (ie. tracklogs). With my old Garmin 12XL I just wanted keep tracklog records for later viewing in a PC mapping product.

 

I suggest that you both still have a look at the GPilotS program and a "serial" Palm PDA. This may be able to do what you want, i.e. store routes in excess of the 25 limit on the Palm and upload them when required to the GPS. You will need a gps to PDA cable.

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Hi Joe,

 

I misunderstood what you and norScot were wanting to do. Confusion between tracks and tracklogs. I now gather you want to store tracks (i.e. routes that you want to follow, possibly repeatedly) and not follow, or necessarily store, where you actually went previously (ie. tracklogs).

 

This is not exactly what I'm looking for. I shall be trekking in the mountains for 4 weeks, and I want to record where I have been, so that I can review the tracks later (particularly in Google Earth) and add my photos. I won't ever reload these tracks to my GPS. My concern is that the 10'000 available track-points may not be sufficient.

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First, the usual meaning of track and tracklog is the same. A recording of where you've been.

The word "route" is used to describe where you want to go.

 

Second, the tracklog has it's own memory area. Deleting waypoints does not give you more tracking memory, as they don't share the same area.

 

You can use saved tracks as routes, since you can ask for trackback along the track. The unit will then direct you along the path of the track.

 

When walking in the mountains for four weeks I don't think the 10000 points will be enough either. Since the unit can store 20 tracks, I recommend you clear all saved tracks, then start saving them every second day during your trip. Thus you can keep on for 40 days. It's true that it will reduce the resolution of the tracks when you save them, but at least you have something. You can also set the recording mode to Automatic - less often, or least often, to avoid sampling track points to the current log too often. Resolution will suffer, of course, but it's simply impossible to have both at the same time.

 

As for logging to the card (assuming a 60 CSx), you get one track each day. Then you upload them to the computer (Mapsource), edit them as you like to cut off what you don't want in a track, filter them down to max 500 points, if there are more points in the track, then download the track to the GPS again, as if it was saved in the unit. Now you have a track you can backtrack later on.

If you want to do some more work, you view the track on the computer, then draw a route on top of it. If there are no roads on the map, then you have to use a direct route, with straight lines from one intersection/turn to the other. A 60 CSx can store 50 such routes, each having 250 viapoints (when it's a direct route, autoroutes can have 50 viapoints, but they require roads). Thus you can at least build a library of 50 routes in the unit, to use when necessary.

 

The only Garmin model I'm aware of that can have a virtually unlimited library of routes to call upon when necessary is the Zumo. It has support for storing the routes and tracks on the SD card. Then import the one you need when you need it. Delete something from internal memory first, if necessary.

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Thanks a lot Anders.

Do you have any idea how often track points are saved in the Automatic - least often mode? Is it speed-dependent? I would really like to quantify (even as an estimate) how many points I'm going to generate in 4 weeks, but when I look at tracks I can't see much consistency in the time or disctance interval.

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There shouldn't be.

 

To visualize how automatic mode works, you can think like this:

Say that you start at a point we call A. You begin walking along a straight line in some direction. After a certain distance, you make a turn. A new point, B, is generated to log where you made that turn. Now imagine a straight line projecting through A and B. As long as you keep going within a certain distance from that line, no new point will be generated. But when you stray off far enough, point C will be dropped, and a new imaginary line through B and C will be projected. As long as you are near enough to this new line, nothing happens. When you go too far away from it, point D is registered. This sequence keeps on repeating itself over and over again.

Obviously, with the setting "most often", the tolerance for deviations from the line is smaller than if you have "normal", and even more compared to "least often", of course.

 

This is a rather intuitive way to understand automatic recording mode. The more stable your trajectory is, the less points required. Some early units actually specified the tolerance in meters, instead of the more subjective more or less often. But today's units factor in not only your position, as you move. They do about the same calculation for your speed and elevation. So to avoid logging new points you must follow a straight line at constant speed and elevation. If any of the three change too much, a new point will be used.

 

Driving 10 km along a straight highway, with cruise control engaged, may very well use less points than walking 200 meters along a track in the woods.

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Thanks for a very good explanation, Anders. Unfortunately, I don't think I'll be travelling far in a straight line in the Himalayas. However I've just thought of another approach: say I trek for 25 days, and cover 20km each day, giving a total of 500km. I'm only interested in the time when I'm actually moving, so if I set the GPS to record every 10m (which I think is very high resolution for a track), then I have only used 5'000 of my available 10'000 points.

 

So no problem! No expensive upgrade o 60CSX, or have I missed something?

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Automatic mode will not save points when you are staionary either, assuming the air pressure doesn't change too much, or it will believe you are travelling vertically.

But you are right in that 10000 points will be enough for a point every 50th meter, if you move 500 km.

On the other hand, if you go 20 km each day, and save the track for that day, the reduction to 500 data point gives you an effective capacity of recording once every 40 meters.

You can only save 20 tracks, but the last five days will easily fit in the active log, which is there in addition to the saved tracks.

Hence I would recommend that you start out with clearing the track log, then set it to automatic and normal.

After the first day, save the log and check how much of the log has been used (in percent). Assuming it was less than 50%, continue the next day, save the log for that day only and check the percentage again.

Soon you'll have a feeling for how many percent of the log you need for each day. Remember there's a calculator built in!

Once you know that, you can easily estimate if the active log will be sufficient for your last five days, or if you need to adjust the more/less often setting to accomplish that. Until you reach day 21, use it in normal mode, to get a good resolution for the active track. It will be reasonably reduces in the saved logs anyway.

When you do reach day 21, you've had 20 days to figure out if it should be less often, more often or whatever.

 

This method also adjusts for that you may cover a different distance then you expect some days. Your planned 500 km in total may end up being a bit more. With your idea of 100 meters fixed distance, you are ready for 1000 km, but you loose resolution if you don't need it all. My method will give you the best resolution you can have. The only thing you don't get in the save tracks is the time information, so if that's very important to you, you have to go your way.

This assumes that the 60 CS does clear that information from the logs, of course. My old eTrex Vista does, but my iQue 3600a does not. I noticed now that the 60 CSx does remove timing data, so I assume it's the same for other 60-models.

 

But apart from that, I'd say this is the most effective way you can use your GPS' features.

Edited by apersson850
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This is not exactly what I'm looking for. I shall be trekking in the mountains for 4 weeks, and I want to record where I have been, so that I can review the tracks later (particularly in Google Earth) and add my photos. I won't ever reload these tracks to my GPS. My concern is that the 10'000 available track-points may not be sufficient.

 

Seeing you only want to view where you have been in Google Earth, MapSource etc then I suggest that you upgrade your gps to a 60Cx or 60CSx. The extra cost is really just the difference between what you could get selling your CS and the new purchase. For a trip of a lifetime that is just small change. For that you get a much better unit. With saving your tracks to a 2 gig card you won't have to worry about any old 10,000 trackpoint limit. As for resolution, from what I have read (just check the maths) you could set the gps to record trackpoints at 1 second intervals and still have room left over on the card. Your tracklog is saved daily to the card (as day-stamped gpx files) and you will have your trip saved in 28 days of gpx files. You will be able to edit each file when you get home to remove the stuff you don't want.

 

Enjoy your trip.

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With saving your tracks to a 2 gig card you won't have to worry about any old 10,000 trackpoint limit. As for resolution, from what I have read (just check the maths) you could set the gps to record trackpoints at 1 second intervals and still have room left over on the card. Your tracklog is saved daily to the card (as day-stamped gpx files) and you will have your trip saved in 28 days of gpx files.

Found the source of where I had read how much memory a trackpoint takes. It is here. Read the 2nd para of the "Pros:" section. Saving at 1 second intervals for 28 days will require storage for 2,419,200 trackpoints. At 1.3 Mb per 10,000 trackpoints this will use up 315Mb of a microSD card. If you have purchased a 2 gig card (why not they are so cheap nowadays?) then you would still have approx 1.5 gig left over for maps, POI etc - some storage is required for card management.

 

Enjoy your trip.

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Thanks to Anders for the elegant workarounds for managing limited storage capacity.

 

However, I'm following BaldEd's suggestion and upgrading to a CSx, so all my troubles will be over until Garmin come out with the next generation.

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