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Memory Use out of control on SD card

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    Hi, I have a Samsung Galaxy Tab A tablet that has only 16GB of internal memory so I use a 64 GB SD card for all map storage and for the location of temporary files (set within Avanza app). I have a series of map collections that refer to my project area and these total only 6GB or 8GB, depending on the project. The app crashes often while using the collections (not a problem when using a map folder with single maps however, regardless of individual size) and the memory usage on the SD card is out of control. So I have a total of 14GB of maps (all user made) but the SD card tells me that 62GB out of 64GB has been used! Seems crazy – all I use the tablet for is Avenza. So what is going on here? can I clear the maps folder once the maps are loaded into a collection? Is there a cache issue that needs resolving? are the crashes storing lots of junk data someplace that I need to delete it from? It is really becoming a problem. I imagine that the App only needs approximately the same amount of space as the maps (say 14 GB in this case), so what can I do to free up what seems to me to be obviously-wasted space on the SD card?


    My SD card is a nominal 64 GB (actual 59.6 GB)
    Currently showing only 3 GB free/ 56 GB used

    The maps folder is 12 GB
    The Android/data/com.avenza/files folder is 24 GB
    The rest is basically zero (a few MB).

    So what happened to the other 30 GB? – This looks like a generic SD card partition issue.

    I think I need to create a new 30 GB partition on the SD card but in order to do this without risking my 232,795 files in 686 folders (actually 803 maps in 61 folders) I will make a backup first.

    I will let you know how it goes.



    Thank you for your additional posts regarding memory usage with SD cards. When it comes to SD cards, there is often a certain amount of space that is used for system loading, as well as the SD card partitions as you mention. Similar to a device hard drive, you never truly get the space they say you are going to get. In regards to Avenza Maps and caching of data, when you process custom made maps from an external source, such as an SD card, the map processes into a series of tiles for use in the app. This processing takes your original file size and will expand it significantly resulting in a larger file size taking up space. Unfortunately, in order to have maps usable in the app, this is unavoidable. Once the maps are loaded into a Collection, you will still need to maintain the maps folder on the SD card as this is holding the processed maps that the app is referencing. If you remove any processed contents from the SD card (or remove the SD card), they will no longer work in the app and you will need to start over.

    As you mention you are using an SD card with over 800 maps on it – this is a significant amount of data that can cause processing, memory and general performance issues. Are all of these maps stored within the app as well? The issue at hand may not be the SD card itself, but the CPU, RAM (depending on which model you have, Samsung Tab A’s generally only have 1.5-2GB of RAM), and processing capabilities of your mobile device instead, as regardless of the source of the files, it is the one that is going all the heavy lifting so to speak.

    Please feel free to contact our Support team directly ( and we would be happy to answer any further questions you may have.

    Avenza Support


    Thanks Kate, I see what you are saying but I thought using collections was the way to handle this? The 800 maps are all organised in collections of about 40 maps each. Each map is only 10-30 MB (optimized PDF’s), so when a collection is open only one actual map is open from each collection at a time. The users switch between the collections which each have a theme (ie imagery, topo, geology etc). So overall the performance time/speed/functionality seems to be pretty good. The main problem was the memory usage of the SD card (filling it up). The 2:1 ratio now makes sense (tiling) so I just need to allow 3 x the map folder size for the overall storage overhead. If I can sort out the partitioning then I think I have a winning solution to my storage problem.
    Due to the cost of the larger SD cards, it would be neat to be able to use a smaller (64 GB) card for each project and be able to simply insert the right card for the job, without having to *sigh* load all the maps again by hand each time. The way I see it, I should be able to pop in the right card, open Avenza and have all the collections for that card right there and ready to go.


    Update re SD card:
    There was/is 20 GB of ‘missing’ space on the 64 GB SD card. I can’t access it via a new partition (tried that, the SD card is a single partition already; only 15 MB is unallocated).
    I loaded up Folder Size Explorer, and that only sees 36 GB of data in the folders, but tells me that 95% of the card is in use.
    I have unchecked the “hide hidden files” in Windows Explorer (nothing new to be seen).
    I copied all the data from the SD card onto the C-Drive of my laptop and… it only shows 36 GB of used space. Good, right? Not really.
    I copied the folders from the C-drive onto a brand new 128 GB SD card, and…it still takes up 56 GB!
    Next issue is the Microsoft ReadyBoost setting on the SD card. Android doesn’t take advantage of this feature so it is useless unless you have a spinning HDD, which the tablets don’t have. If it is turned on it will grab a large chunk of the SD card for use as a kind of virtual RAM. Google it if curious.
    So I turned OFF the ReadyBoost function on the cards and expected to see a reversion to larger space, but this did not happen = no change.
    The next worse news is that when I put the original 64 GB card back into the tablet and launched Avenza…nearly all my Collections are gone! There are only 5 left out of 12.
    When I put the 128 GB card in, it is the same thing (same 5 are retained, the rest are gone).
    The individual maps are still on the SD card and I can create a new collection (great…) but for some reason the other collections have vanished.
    So, is Avenza actually taking up 4.5 x the space of the maps folders instead of 3 x? Why can’t I see this used space?
    From what I can tell it is not a function (at all) of the SD card, so that leaves me thinking it is something to do with the Avenza App itself.


    I formatted the 128 GB SD card and made sure ReadyBoost was switched off.

    Then re-copied the maps folder (via the C Drive) from the 64 GB SD card.

    Still shows 56 GB used even though the folder is only 36 GB on the C-drive.

    Map collections are no worse (still 5 of them) but no better, but at least I now have the 128 GB card as the main storage card so can rebuild the collections from here and should get a few more projects on it before we have to retire/delete the SD card and/or buy another SD card for the next series of jobs.


    Hi Arjan,

    I just wanted to touch base and see if you were still having problems with the SD card? The amount of space that individual maps take up varies from map to map based on scale, zoom levels, etc.

    In regards to not getting the full amount on your SD card, this is not uncommon with storage devices, as they often have reserved space for built-in mechanisms that are not always accessible (depending on the exact card, brand, etc.).

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