OpenStreetMap

Documenting Process for Creating GPS Traces

Posted by DougPeterson on 5 February 2015 in English (English)

I thought I would record what I do for traces for any future reference. This applies to walking or driving traces.

For hardware I use a Holux M-1000C Wireless GPS Logger. This is an external bluetooth GPS receiver I use with my phone. Prior to June 2013, the phone I used was a Samsung Galaxy S. After that date I have used a Samsung Galaxy S3.

The GPS on my original phone was particularly bad. I believe when the Galaxy S was originally released the GPS was basically broken. I was primarily using the GPS in my phone for geocaching so the poor accuracy of the GPS was frustrating. I also drained the battery quite quick between the GPS and downloading maps. Improving accuracy and battery life were the main reasons for getting a separate receiver.

For software I use Locus Map Pro. Locus Map has good geocaching capability as part of its significant mapping capability features. The reason I was looking at a mapping application for geocaching was that I was looking for good off-line map capability. Locus Map can store tiles for off-line use or use off-line .map files rendered by the Mapsforge library. I have a limited dataplan so all the maps being downloaded for geocaching were using up all my data.

I started mapping on OpenStreetMap to improve areas I wanted to do geocaching in; for example, parks. There are phone applications focused on collecting OSM data. However, the ones I have tried all use on-line maps so that is not desirable for me. So I continue to use Locus Map to record waypoints of amenities or features I wish to map. I create my own off-line maps using a Mapwriter plugin custom tagging file with Osmosis to create the file and a custom Mapsforge theme to render the map. That way I see everything I add on my phone.

I created my own recording profile in Locus Map to save a point every 1 second AND 1 meter. The default accuracy is unchanged at 100 meters, meaning it will exclude all points whose accuracy is worse than 100 meters. This could be lowered but I am not sure it matters. Bad data would tend to be obvious visually and I have not noticed a situation like this. The profile will record points while standing still. I leave it that way for trail mapping as I will come to deliberate halts to better draw the trail, particularly at trail intersections or sharp corners. I would not want to lose that visual information. It will not record Cell ID information which is an alternative to track recording if GPS is not available. I have not experienced that situation.

I do clean up some of the traces I upload. This is typically in the case where I did not shut off the recording soon enough and I went somewhere that might be misleading. There are also sometimes scribbles (I read that description somewhere) where I was going back and forth in apparently random directions that make for a mess in the track visually and created data of no real value.

There are other things or behaviors I do as part of tracing. I have excluded them from here as I was focused more on recording the technical details.

Comment from joost schouppe on 6 February 2015 at 13:25

I just use Osmand on my LG G2. Quality seems good enough to me, but of course, I’m using it mostly in not so densely populated areas. Here’s an article I wrote about how to use Osmand to contribute to OSM. And here’s a pretty map of the tracks I’ve been uploading to OSM over the past 9 months.

Comment from DougPeterson on 6 February 2015 at 18:10

I have looked at OSMand and other free OSM based navigation tools such as Navfree, MapFactor Navigator or Be-On-Road. I thought OSMand had the most features and had better features for contributing to OSM. There were some others that were nicer to look at. OsmAnd seems like a good choice for a single tool, depending on what you are trying to record. It might avoid having a second tool like OSMTracker.

The navigation tools are going to be more focused on navigating and may not include things that would contribute to screen clutter and confusion. I think that is appropriate to their purpose. One thing about the free version of OSMand is that it limits you to ten free file downloads, which I think includes updates to map files you may have already downloaded. If someone is interested in OSMand then it would seem worthwhile to buy the full version OsmAnd+.

For me, the issue is that all the navigation tools use their own map files. I want to see all the items I am mapping on my phone or tablet. That includes seeing things that I have already mapped. That is why I use my own tagging file with Osmosis and my own theme in Locus. I can make my phone’s map look a lot more like OSM on-line. In some cases I am displaying things that are not displayed on-line, such as survey marks.

Comment from Alan Bragg on 28 February 2015 at 14:10

Very nice write-up. Thanks for the information. I have an Iphone 4 and use the Galileo app which allows great off-line use of OSM vector files which you download state by state. I set the accuracy threshold to 32.8’ nd the distance threshold to 0.0’. I too have switched to an external data logger, the Garmin Glo (Built-in antenna · Bluetooth · 0.7″ x 3″ x 1.6″) which I wear in the crown pocket of my Tilly hat. I like the rechargeable battery.

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