Resolution

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Joe D

27 Jan, 2019 05:11 PM

The app is great. I did have one question though.

I currently use Avenza. The workflow is to create a map in Caltopo, save it as a big PDF (48x48) with my caltopo pro account, then upload it in Avenza. I mostly use the Forest Service 2016 layer with enhanced relief added. I use very little in-app functionality when I'm out -- I basically just want to see where I'm at on the map.

The problem with the Caltopo app though, is that after saving high resolution tiles of the same area/layers of a PDF that I have in Avenza, the resolution isn't as good. In the app I zoom into an area, then bring Avenza up using the same area and zoom, and the Avenza map is clearly the sharper, more usable image. Am I missing something? This isn't a ridiculous zoom either to some 10 meter section, but a view that'd I'd commonly use when out and about. And when I look at the offline layers part of the app it does confirm that the area I tested is saved in high resolution.

  1. Support Staff 1 Posted by matt on 27 Jan, 2019 11:21 PM

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    That doesn't sound right, the resolution should be the same as the website and at least as good as the PDF (since the PDF images are stored as JPEGs and there's a small amount lost due to the lossy compression).

    Are you sure you downloaded high resolution tiles for both the FSTopo and Elevation layers? If you look at the map with an internet connection available, do you encounter the same low-resolution issues?

  2. 2 Posted by Joe D on 21 Mar, 2019 05:33 PM

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    Sorry for the delay Matt. Nothing like putting a comment out there and then going quiet...

    Anyhow, It appears to only be a FSTopo 2016 issue. Even connected to a good internet connection at work that layer isn't sharp for me. When switching to FSTopo 2013 or any other layer while connected it works great.

    Offline, it's the same: FSTopo isn't sharp but MapBuilder Topo, FSTopo 2013, etc. all are.

    Another couple of questions... I'm really enjoying MapBuilder Hybrid while planning on my desktop CPU. Any way to approximate that with an offline layer in the app? I'm downloading the 2015 Imagery offline layer now, so maybe something like adding that as a second layer at a lower percentage? It's not a big deal, but I just want to make sure I'm not missing anything.

    Also, I was wondering about deleting offline layers from the phone. When I get into the "tiles" folder on my phone, some layers are clearly labeled (mapbuilder_overlay, naip_2015-2m), while others are less clear (dem, f-2m, canopy). I could see in the future asking a user to designate a folder where the download is going, that way it's easy to delete. Unless there's an in-app way that I'm missing.

    And a suggestion: It'd be nice to have some kind of download progress bar or something, especially while I'm at home on a really slow connection. At this point I know to just click download and leave it for a while, but initially it was confusing as to whether it was working but slow, or something was awry and I should re-download. Obviously not super important and maybe not worth the effort.

  3. Support Staff 3 Posted by matt on 21 Mar, 2019 05:57 PM

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    What lat/long are you looking at?

    If you've downloaded a recent imagery layer and the MapBuilder Topo layer, MapBuilder Hybrid is automatically available - that's why it's not listed as a separate download.

    File naming needs some documentation, but dem is elevation data (digital elevation model), f-2m is the high resolution (2m) forest service data, canopy is canopy shading used by MapBuilder Topo. Last part of the file name is the lat-long block and then the 15x15 minute grid within there. I'd recommend backing them up onto a desktop rather than just deleting them, so that you can copy them back if you want.

    Download progress should show up as an Android notification separate from the app, similar to what you'd see when downloading a large file in Chrome. Let me know what Android version you're running if that doesn't show up.

  4. 4 Posted by Joe D on 21 Mar, 2019 06:21 PM

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    Location is the northern Big Belt mountains in Montana, roughly 46.8045, -111.6816.

    Great to hear about MapBuilder Hybrid. I will give it a try when the imagery download is finished.

    Thanks for the file naming tips and the advice to backup. I will do that.

    I'm using Androind 7.0, and lo and behold! There's the notification once I go in the app manager and allow Caltopo to give notifications. That's an easy fix.

  5. Support Staff 5 Posted by matt on 21 Mar, 2019 08:44 PM

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    I downloaded offline FSTopo 2016 tiles for that area and it looks ok to me in the app. Are you able to send a screenshot?

  6. 6 Posted by Joe D on 29 Mar, 2019 06:58 PM

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    Sure Matt. First attachment is caltopo app, FS2016 with 35% enhanced shading. Second is same layers/scale in Avenza. Avenza is sharper, but where it really stands out is when I zoom Avenza out just a hair, it's perfectly sharp. Caltopo only allows a bigger jump out in zoom, so I'm either out farther than I'd like or in where it's not clear. Really though, I'm using the mapbuilder layers more and more, and as the third screenshot shows mapbuilder_hybrid looks great at the same zoom.

    Other issue: I like a map with aerial imagery and 40' contours. 4th attachment shows that I have 40' contours downloaded for my home range. When using the desktop version, it zooms in from 200' contours to 40' nicely. But in the app there is no zoom level where it switches to 40'. See 5th attachment. This happens in the app both when connected and when offline.

    Also, thanks again for all the support.

  7. 7 Posted by Joe D on 30 Mar, 2019 01:07 AM

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    And another question -- sorry :)

    I have some Mapbuilder layers I've made custom using the desktop version and they're saved to my account. They're also the main base layer in a few maps that I have synced to the app. However, when I open those maps in the app the custom mapbuilder layer isn't there, and from within the app, when I choose Add Map Item, my custom layer isn't available under Layers.

    Do I need to choose Custom Source, at the bottom? If so, I couldn't find the URL for my saved layer on caltopo.com.

    Any help is appreciated if that feature is actually available. If not, oh well.

  8. Support Staff 8 Posted by matt on 01 Apr, 2019 05:00 PM

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    Custom mapbuilder layers are not yet available in the app, although I expect they'll be available before the app gets out of beta (syncing custom mapbuilder layers for offline use is a whole different issue).

    I've discovered a bug where if you have offline data downloaded at different resolutions, it applies the lowest resolution system wide, not the highest. This was due to a late change that switched from tracking layers via zoom levels (highest is best) to meter / pixel resolution (lowest is best), and not properly.

    Your screenshot shows that you have high resolution 40' contours downloaded for that area; do you have low resolution contours downloaded elsewhere? (although I'd expect to see what you're seeing with the USFS maps, which is a one-zoom-level difference; the contour screenshot you sent looks much worse.

  9. 9 Posted by Joe D on 08 Apr, 2019 03:51 PM

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    Thanks again for the great support.

    I'm not sure what other levels of contour downloads I have. What are the files called? I see both a C-2 prefix and a C prefix before the lat-lon blocks of the area I downloaded, if that's the file name.

     Also, is the imagery defaulting to lowest resolution as well? I see in the download folder that there is NAIP_2015-1m, NAIP_2015-2m, and NAIP_2015, which I presume are all three levels of NAIP imagery, even though I only chose the 1m download.

  10. Support Staff 10 Posted by matt on 08 Apr, 2019 07:39 PM

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    The contour files are available as c-. No prefix is the low-resolution download, which contains all zoom levels down to a certain point (zoom 15 for NAIP and contours). The -2m and -1m have 2 meter and 1 meter resolution data (zooms 16 and 17) only, ie you need all 3 files to form a continuous layer.

    Hope to get a new version of the app that fixes this out soon.

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