How I'm doing it now

Posted by Freebourg on 23 August 2011 in English (English)

3 years since my last entry, and not so much upload last year.
Well, life has continued since then.

OpenStreetMap has changed too.
From the weekly updated map with a big portion of blank parts, it's now one of the best available online map, and the most accurate one for sure, when mapping has been done.

While, 3 years ago, I could just go anywhere and be almost sure the route wasn't mapped. I know have to do that differently, based on my knowledge of things (which is a limited 10 km area) or by comparing satellite views or other maps to get an idea.
It's also more necessary to pay attention to all the tiny details. Because you often find roads and streets, but the POI are missing.

When I look at what I published here in 2008 about the hardware. It justs feels like a joke today. Come on, 2 MB?
But that is what the society and the marketing says.

I'm now using an Android Samsung Galaxy S phone to record GPS tracks. It works, but I find it less accurate, but the worst problem is battery life, and the fact that you can't just throw it in your bag and forget about it.
So, tracking in a car with a mobile power outlet is OK, but if you're going on foot or any mean of transportation without power supply, the smartphone just won't do it.
I found the Android application for OSM mappers to be useful. I only use its short-geopositioned-audio-files-recording capability, and it really saves time.

I've previsously worked with paper and pencil before. And, to be honest, it wasn't that bad. It's also easier to thing about where you will be heading in a second, when you do that. The problem is, this takes time, and you're not as fluid as just "talking". You must stop everytime to take note of street name, POI, etc.
The difference is the price. $500 smartphone vs $70 Bluetooth GPS data logger.

If you bring your computer in your car, I found my USB GPS mouse to give the most accurate results. The fact I can put it on the roof certainly helps.
The nice thing about the laptop, is that you can view your GPS accuracy (how much GPS in sight, quality of signal), log much more than you could possibly do in your entire life, no lag of system, ability to show the route taken on a map with background, ability to open images, etc.

I own a MacBook Pro, but couldn't make my GPS device work on it, despite installing kExt modules.
Sorry but you won't find better GPS support on any other OS than Linux.
gpsd is just the best thing invented since sliced bread.

Comment from nmixter on 24 August 2011 at 05:07

$500 dollars for a smart phone? What is it a rolls royce? My 150 dollar android phone does fine except for the battery life. Anyway that is the nice thing about osm is there are many ways to contribute

Comment from Freebourg on 24 August 2011 at 06:43

Well, considering the $650 price tag of an iPhone 4...
If you are only looking for a GPS logging capable smart phone, $150 is fine.
I paid $350 for a 1 month used Galaxy S, and I find it very cheap for what it is honestly.

A Garmin eTrex for example is $250, so...

Comment from dkj on 24 August 2011 at 07:06

the recent smart phones seem to be quiet good for gps tracking. Accuracy sometimes not perfect, but even my Locosys GT-31 accuracy fails sometimes by 10-20m, especially in the mountains. Yet with the new Bing-Ovelay in josm it is much easier to find this kind of problem and create extremely accurate mapping.

Yes, today you have to search for the areas where the map needs work. Yet I found a lot detail work still needs to be done, many small villages still badly mapped, or the mountain tracks in the Alps sometimes are not very accurate, sometimes straight wrong.

BTW, the Nokia N900 mappero software shows you the accuracy of the gps as a circle on the online or cached map.

Comment from HannesHH on 24 August 2011 at 07:39

The accuracy only means that your GPS thinks that your current position is somewhere inside a circle with that radius. Where that circle is in relation to your actual position, it does not know!

It is so misleading how software presents those values and I myself only found out about this years after I started using GPS.

Another option for smartphone based tracking would be using a bluetooth GPS receiver. With Android it is a piece of cake to use (I use BlueGPS).

Comment from Freebourg on 24 August 2011 at 08:26

Yes, but if you have a good GPS reception with no window/roof in-between you get a 5m radius, while otherwise having a 15-20 m one.
I found speed to be another important factor to consider. Because the position is updated once per second, if you go faster than 35 km/h, your position will be updated less than every 10 meters. Then biking is fine.
Most devices I tried aren't that good when it comes to tracking on foot.

A direct satellite facing GPS device is also less prone to lose signal, and it will "see" more satellites.
3 satellites in view is necessary to get a 3D fix.
Because you can lose signal or have a weak one, the more satellites in view you have, the better the accuracy of the mapping.

There is no point to create a path on JOSM following the exact position of each logged GPS point. The goal is to get an idea of the shape of the road. It wouldn't make sense neither because GPS is not accurate enough. If the GPS track shows something like /\/\/\/\ (with less angles) the road was probably straight.

I'd like to see a weather-sealed Bluetooth GPS mouse/data logger with long battery life that would provide a better solution compared to smartphones internal GPS.

Thanks for your comments.

Comment from Rovastar on 24 August 2011 at 20:24

Yes, a lot has changed over the years, amazing really. You do know that we can use Microsoft Bing imagery to trace the detail? It is a recent addition in the last year or so and used in conjuction with the GPS can make very accurate maps.

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