Portable maps- Are they truly offline maps?

[Narayan Aras]

Hi

Question:1 Are the portable maps truly offline maps?

In other words, suppose I view a city in the map with zoom level 1 (the lowest zoom factor).
Then I zoom in to the next level (=2) and view the entire city
Then I progressively go closer (up to level 18) and systematically scroll across the city to ensure that I have not missed any area.

In this case, will GPSE remember the entire city as a portable map?

Or will it start dropping tiles when the memory reaches a particular limit?

Question #2: Can I update the portable map in different sessions?
Suppose I keep viewing the same city in different sessions, and each time I see new areas.
Will GPSE keep adding these new areas to the previously stored map?
(That means eventually the map for the whole city would be stored on my mobile.)

[Michael Schollmeyer]

In the current version of GPS Essentials (including 3.2.12), the app maintains a database and stores all map tiles it receives into this database. You can backup or copy this database (it's in com.mictale.gpsessentials/databases). There is an expiration time for every tile, specified by the server, defaults to one week. After this time, the tile remains in the cache but whenever you load it again the app will also see if there is a newer version on the server. Distinct from expiration, there is a limit to the sum of all tiles in the local database. When you exceed this limit, GPS Essentials will erase least recently used map tiles. You can change this limit in settings.

Starting with GPS Essentials 4.0, the behaviour will change slightly. There will still be expiration and limit, but map tiles will be managed in streams, so you can delete them by map type and (in future versions) you will also be able to import, export and share them.

Cheers, Michael
mictale.com/ms
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[Nathan Asdourian]

Hi Michael,

I've had your program installed for a number of years and only used it for the access to the altimeter info from gps. Lately I have been looking much more closely in hopes that I am able to utilize it for a project I am working on for the 4 wheel drive group I am a member of. I currently am using version 4.0.32. 

Would you have any interest in somewhat expanding your support for offline use?

Since you will likely want more info before answering that, I will give you a little background of what it is I'm doing, What is currently needed, and what my vision for the project is.

The group I am a member of is a registered non profit, and was approached a number of years ago by the Barstow office of California's BLM (Bureau of Land Management) in hopes that we would be interested in creating a new trail within an OHV designated area. The group accepted and set out creating this trail, which over the years ended up going back and forth on a number of issues, all which recently have been resolved. Next Thursday May 1st will be the official opening of the trail. Along with that they are having the state commissioners on site for a tour of the grounds, and a number of different presentations are being given, myself being responsible for a bit on new trail technologies that we are testing out and working on.

I have been working on setting up a publicly accessible, self contained wifi hotspot to be located at the trail head. The device will have NO access to the internet, and will be powered by a solar panel, with a small battery to ensure proper shutdown each night. Specifically what I currently have in progress is a Raspberry Pi running Raspbien and a customized version of PirateBox. Once connected to it, using a web browser to open any site results in redirection to the local web server, and provides access to a file listing. Initially there will be a PDF map of the area, as well as .gpx files that contain very detailed gps routes, as well as track logs for the nearby trails. 

The first issue we come to is that since this is not something normally done, very few people are likely to already have an appropriate program on their phone, and even fewer are likely to have previously cached the map tiles. It also will provide a repository where people can upload a tracklog they create for us to consider making available to others.

This brings me to the second issue, If you check the attachment you will notice that due to the size of the point markers, and lack of any way(that I have found) to hide them, such a detailed route results in the map being very difficult to use. 

The last issue is with the route guidance , I tried to play with this but not knowing exactly what various icons are for, it seems that something isn't very happy at the moment because numerous actions partially crash the app.

I do for some reason seem to have a continuing issue with the pop out menu thing, on my phone for whatever reason it is extremely jumpy and finicky. I tap it, nothing, tap again, nothing, tap again opens then closes right away, tap again same, again opens. try to rotate it, rotates a few degrees then closes...Even using the stylus for my phone I have the same problem. I'm guessing this is likely device related, but it looks like it allows for both tap to open and drag to open, with the drag closing when you lift your finger, and tap not closing...maybe an option to select only one method would take care of the problem on touchy devices?

My thoughts on some ways to handle these issues which would make everything much more usable for backcountry use, so you can get an idea of at least initially what might be involved. It's also possible that it could be handled by a plugin?

#1 Not having the app installed is easy for android, I can easily provide the apk file along with instructions on loading it

#2 Not having the maps cached is somewhat more challenging. I am currently reading up on rendering my own open street map tiles in order to get an overhead map view that doesn't have the restrictions pertaining to downloading. Once I manage to do that, I will need some way of packaging the tile set into a single file, then an easy way to load that tile set and change the map type to use that set. 

In the meantime, it would be a significant help to be able to export the cache to a file, though currently I am unable to bulk download the mapsource tiles, it tells me 3k to download and will go 7-10% then just stop. hitting back then crashes GE and if I attempt to start the download again, it completes very quickly and is obvious that it didn't actually do anything.

Ideally it would be nice if this package could also include the waypoints, routes, and track logs in order to reduce what is required while you are essentially standing at a kiosk in the desert with the rest of your party waiting...

#3 for visibility on the map, an option to hide the markers for waypoints associated with a route(unless you are navigating to that particular one) be hidden from view.

#4 for the route guidance, there are a few things, some of which may already exist in your program.

a separate icon that specifically goes into this mode would likely be a good idea, since you could then make a few assumptions, namely that network access won't exist...

On selecting this mode, a list of nearby routes should be presented, perhaps defaulting to a particular one if you are within x distance of the starting point.

after selecting a route(trail) a quick evaluation must be done and if the person is somewhere very near another point on the trail, it should ask them if they are mid-trail and provide the option to either start from the beginning(route to the first point of the route) or resume the route from where they are(route to the next nearest waypoint based on where they are)

The screen at this point should be as simple as possible and not require the device to be in a particular orientation(ie laying flat on something with the screen up)

The main object on the screen being a navigation arrow, pointing you towards the next waypoint, and automatically moving on as you go by each one. it will need to have some intelligence built into it on whether it should move on based on direction of travel during approach. basically it should correctly handle for example if there is a waypoint at the bottom then top of a hill, and a switchback going up the hill.

some form of line on the arrow should also indicate whether or not you are actually on the trail you think you are...so if gps says your 15ft over, the line would be off to one side so you can recognize that you aren't on the right trail rather than realizing it when one of the trails turns off.

A few things to note, while auto-advancing is desired, it should not automatically skip more than 1 or perhaps a configurable number, without prompting.

Some other things could be displayed below or to the side, such as the moving average speed(typically around 3-5mph for our particular group) distance to next nav point, distance to completion, distance to final point, ETA at finish, altitude, total ascent/descent.

One Idea I did have was that it would be very awesome if we came up with a specific app, along with a service that ran on the trail head wifi point, where you connect to it, then open the app and it handles the data downloads for the user along with anything else needed.

It would be nice for a tracklog to be created, so if they are interested in checking in on the way back to camp, we could get a sense of how quickly they moved through everything, and whether they went around particular obstacles. Which would aid in future updates to the trails, as well as whether we need to add go-arounds, or even eliminate parts of a certain trail.

Well, before this gets any longer I'm going to post it, I need to go dig through my electronics stash in search of some parts for creating an uninteruptable power supply.

I hope to hear from you soon, 

Nathan

[Michael Schollmeyer]

Hi Nathan,

Thanks for the very elaborate post. I hope I can cover all issues:

First, there is no "native" export format in GPS Essentials. I am planning to build one and then you could prepare a stream, export lossless into the native format and host this file on your box. The next thing that comes closest to that is KMZ. I recommend you record your track data along with some hot spots (you will already have done this) and then build something using Google Earth. G4 now supports a much wider subset of KML. You could try the following layout:

KMZ Root
Round Trip
Trailhead (Placemark)
P1 (Placemark)
P2 (Placemark)
...
Trail
Polyline
Map (Folder)
Image1 (ImageOverlay)
Image2 (ImageOverlay)
...

This is in KML terminology. KMZ is good because the file can be self-contained. The round trip is a set of nodes in G4 that the user can follow. He opens the round trip and presses "Start", G4 will pick up the nearest waypoint and start from there.

The trail is just a visual representation.

You can use ImageOverlays to add a background map to the stream. Here is a video that shows how to do this: http://www.youtube.com/watch?v=2Z61FrCynKE&list=PLZ76pL0pHrbxP0CAOL0S_GVp95IkEhDIs. This is a good way to work around tiled maps because you cannot host them in a KMZ file. With G4, a slippy map (that's a map that reads from a map tile server) is just a stream so you could share it, but you need to be online for this (And sharing is currently limited to 100MB). There is a size limit for image overlays that is device dependant. It might work on your device but not on older devices.

You could also add the sibling trails to this file, but remember to keep it simple or people might get lost.

I'll respond to your G4 issues in a separate thread.

Cheers, Michael
mictale.com/ms
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> <2014-04-26 17.13.50.png>

[Michael Schollmeyer]

> This brings me to the second issue, If you check the attachment you will notice that due to the size of the point markers, and lack of any way(that I have found) to hide them, such a detailed route results in the map being very difficult to use.

This is because you probably used GPX to import the data. Either try KML (or KMZ) or fix it manually, e.g. select the stream, select the category with your nodes (from the top drop down), select Style from the menu and change to polyline.

> The last issue is with the route guidance , I tried to play with this but not knowing exactly what various icons are for, it seems that something isn't very happy at the moment because numerous actions partially crash the app.

Please try to be more precise, I'm more than happy to fix crashes.

The most important new thing about G4 is that you can follow any sequence of nodes in a stream. Either you press start from the Route card which starts from the nearest node or you long tap on a node and select the navigate icon from the menu. Then you can switch forth and back between the nodes in the Route card or stop the route.

> I do for some reason seem to have a continuing issue with the pop out menu thing, on my phone for whatever reason it is extremely jumpy and finicky. I tap it, nothing, tap again, nothing, tap again opens then closes right away, tap again same, again opens. try to rotate it, rotates a few degrees then closes...Even using the stylus for my phone I have the same problem.

Which device is it?

> I'm guessing this is likely device related, but it looks like it allows for both tap to open and drag to open, with the drag closing when you lift your finger, and tap not closing...maybe an option to select only one method would take care of the problem on touchy devices?

Yes, the menu supports both drag and tap usage which is a bit confusing. This is the first iteration and I will improve it. I'm not a fan of configurations though, G4 already has too much configuration items.

>
> My thoughts on some ways to handle these issues which would make everything much more usable for backcountry use, so you can get an idea of at least initially what might be involved. It's also possible that it could be handled by a plugin?

Probably not a plugin, but I am ready to improve usability whenever it fits into the app. G4 has probably become a bit too complex which is great for the avid every day user, there has to be some improvements for everybody else.

> #2 Not having the maps cached is somewhat more challenging. I am currently reading up on rendering my own open street map tiles in order to get an overhead map view that doesn't have the restrictions pertaining to downloading. Once I manage to do that, I will need some way of packaging the tile set into a single file, then an easy way to load that tile set and change the map type to use that set.

You would need a file format that is supported by G4 for import. At this time, there is none (that supports tiled maps). It will probably come in the future.

> In the meantime, it would be a significant help to be able to export the cache to a file, though currently I am unable to bulk download the mapsource tiles, it tells me 3k to download and will go 7-10% then just stop.

If your network is ok it's most probably a server issue. Sometimes it's also very slow, e.g. the server usually caches map tiles but when you're getting close to zoom level 16, the server will generate map tiles and this is very slow.

> hitting back then crashes GE

Is that reproducable? What exactly are you doing? Back should not do anything, you need to tap Cancel to close the dialog. Is it crashing then or when you restart bulk download?

Would you send me your device id? It's in Help on the start screen.

> and if I attempt to start the download again, it completes very quickly and is obvious that it didn't actually do anything.

Bulk download will skip previously downloaded tiles and pick up where you left it.

> #3 for visibility on the map, an option to hide the markers for waypoints associated with a route(unless you are navigating to that particular one) be hidden from view.

Try a different style for this category. Polyline is good for a line without markers.

[Nathan Asdourian]

Reading through your responses, one thing seems rather obvious. My current line of thinking with regards to how mapping and gps programs work, is utterly useless, and I'm thinking it is sort of the root issue here. I don't suppose you have any documentation written up that explains the various concepts and how to use the different features? I do need it to be offline as I will be out in the desert for a week starting tomorrow.well, today...

I did use .gpx as I am used to using garmin mapsource, recently I have moved to using basecamp which redefines how you use a gps program by creating a database then you can link any of the content in as many places as you want, without multiple copies existing.

I believe it does support exporting to .kml, if not directly then by first sending it to google earth, I will play around with using that instead of .gpx from now on.

Given my current thinking, which we now know to be flawed with regards to GE, I quite frequently find myself going in circles trying to do something.

For example I found a screen for the non-road beta route mapping, and it says i need 2 points, then says I have to specify one but I can't manage to do that.

I will sit down and find some bugs for you once I get back, One point that I think  you missed was an off-road navigation mode that points an arrow the direction you should be more or less going, and perhaps has a couple stats you can show.  The reason behind this is that the places we go you frequently must be watching exactly what your doing otherwise you end up needing to be pulled off of something with a strap. so Putting nothing but the next waypoint direction gives you what you need to know, but not enough to distract you with a map.

Nathan

[Michael Schollmeyer]

GPX is a good format when you want to transfer waypoints, routes and tracks as these are the core concepts of GPX. KML is a presentation format, there are polylines and polygons with line width and color, but they are pure presentation, no "meaning". Both formats make sense, depending on what you want to achieve.

Concerning navigation, I recommend you create a route (a stream that has a category with type Route, if you import a route from GPX you will get exactly this). Once you started a route, open compass view. The compass will have an arrow that points to your next waypoint. Also add a few widgets at your preference, e.g. "Distance", "Total Distance", "TTG", "ETA",... There is also a route control widget that lets you move forward and back in your track.

Keep an eye on your battery life!

Enjoy your trip!

Cheers, Michael
mictale.com/ms
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