I'm sure there as many ways of going about building an Open Source map of Ireland as there are formats for storing GPS data, and as a GPS newbie I'm probably going about this the wrong way completely but there's nothing like diving in head first so here's a proposal and attempted bootstrap for one approach.
One thing I've learned, to my disappointment, is that there really isn't the breadth and depth of shareware/freeware GPS software out there that I was expecting to see. Now I'm not one of those people who expects to get everthing for nothing in the software world but in the spirit of building an open source free map of Ireland I think its best to create a framework which can avail of as many free tools as possible so as to make the publication and consumption of OpenEir data as... well 'open' as possible.
Here's a list of the software - with a variety of different licenses attached - that I've downloaded and tried out over the last few weeks.
- OziExplorer
- GPS Trackmaker
- 3D Tracer Demo
- EasyGPS
- ExpertGPS
- Wissenbach Map
- GPS Utility
- MyGPS
Now remember I'm a complete novice at GPS and much of the functionality of these applications remains a mystery to me. I'm struggling to grasp the intricacies of geodetic datums, cartesian reference system, transverse mercator projections and so on. But I don't think you have to understand these things in detail in order to produce something useful. After considering the various options and permutations I decided to work with MyGPS one of the few uncrippled freeware applications. Here's the procedure I followed -
1) I extracted four adjacent 10km radius satellite photos of county Limerick from MapProxy and stitched them together using Paint Shop Pro. I settled the 10km default because anything anything less didn't really produce any greater detail, just a bigger and blurrier image.
2) I imported the map into MyGPS and calibrated it using the MapProxy coordinates.
3) I then downloaded the track and waypoints I captured a few days ago when I travelled from The Square, Newcastlewest, along the N21 into Limerick and then back out along the north of the county via the N69, turning left before Foynes onto the R521 and back into Newcastlewest.
To my delight the rendered track follows very closely along the visible roadway of the satellite photo. I'm not sure why the fit isn't exact, whether its to do with calibration, the position of the satellite, datums, my GPS receiver, or whatever, but in my opinion this quality of projection is plenty good enough for OpenEir.
And here are the first OpenEir files for you to download if you wish -
1) Calibrated map of Limerick (well, most of the county) 2) Waypoints and Trackpoint file for Limerick route
To play with these you first need to download MyGPS, and then import them from the file menu. You can then choose to filter out the track or waypoints and delete the waypoints which are of no interest. You can also create routes using the waypoints and upload as much or as little data to your own GPS unit.
The next step for OpenEir is of course to setup some kind of more organised repository for further calibrated maps and tracks. A Wiki may be most appropriate for that.
What use is any of this? What problems are we trying to solve here? Stay tuned for Part 2...
Your idea has a lot in common with the openstreetmap project. I'd recommend browsing around the wiki, and the mailing lists, to get a feel with what they are working on. Right now it has a particularly London focus, but everything is being planned and developed with the entire world in mind.
http://www.openstreetmap.org/
The reason your tracks are slightly askew from the background imagery is because the Landsat 7 satellite imagery server (which MapProxy interfaces with) is incorrectly callibrated. Generally I've noticed 20-30m shift north of the base imagery. Unfortunately there are no other public sources out there right now, but that should be changing in time.
http://brainoff.com/worldkit/scratch/gps/ : example of another miscalibration on that imagery
http://worldwind.arc.nasa.gov/forums/index.php?showtopic=1512&st=0&p=8513&#entry8513 : confirmation on the problem, and work on a solution
Finally, you might be interested to hear about GPX (gps XML interchange format) support in worldKit. It's unreleased, in alpha, but present in the latest available downloads. myGPS has GPX output options. Currently, worldkit will only plot tracklogs, and not waypoints.
You can add a gpx tracklogs file in the config.xml like this
gpx id="UNIQUEID"URLOFFILEgpx
Cheers
Mikel
Posted by: Mikel Maron | April 18, 2005 at 01:31 PM
Mikel, thank you very much for the great input. Yes, I agree that the OpenStreeMap project has a lot of similarities to what I'd like for OpenEir to achieve and I'm sure we'll contribute to that resource as well. But as a fan of the 'small pieces, loosely joined' philosophy I'd love to see if this can be done through blogging, RSS, tagging and so on, as well as via a centralised Wiki or other database.
Great news about the new features of WorldKit - I'm a big fan of your software and as you probably know have been geotagging some of my blog posts using WorldKit. I'm looking forward to experimenting with it - Please keep up the great work.
Posted by: James Corbett | April 18, 2005 at 10:49 PM
I am looking for a gps map for ireland for driving purposes I am new to the gps game but disappointed that Ireland does not have the 99% coverage that the rest of europe has. can any one recommend a pay for package that gives the best coverage for pda / laptop, I need to nav the major cities but also would be great help to have the town maps for larger towns. There would appear to be a lot of available shareware for all of europe. Sorry if this is not the right forum to ask this question.
any help would be great,
thanks
gerry.
Posted by: gerry | November 21, 2005 at 12:12 AM
Hey,
Great site, got the link from Google, so your efforts to promote the site are working.
Very interrested in your work. I downloaded all the files and info, got the map working and calibrated off the runway in Shannon and Limerick City, imported your .txt file with the waypoints but csnnopt see the route on the map. any idea why???
Living in Clare, so will be downloading maps from mapproxy asap.
BTW what kind of GPS reciever are you using, in the market for one as a christmas pressie
Regards
Posted by: Liam Kitson | November 29, 2005 at 12:00 PM
Thanks Liam, its great to have another GPS enthusiast onboard the OpenEir project! I'm not sure what could have gone wrong with the import - which text file did you use?
I'm using a fairly basic GPS unit myself - a Garmin Geko 201 - because I'm really very new to the GPS field and wanted to learn a bit about it before 'going big'. I also got a great bargain from CharterNavGPS in a sale at the beginning of the year.
Please join in the discussion on the Yahoo! OpenEir Group :)
Posted by: James Corbett | November 29, 2005 at 12:09 PM
what u have done is brill do you have anything for pocket pc
Posted by: jonathan gaspari | April 20, 2006 at 12:58 PM
Thanks Johnathon but unfortunately no, nothing specifically for the Pocket PC. But the idea isn't to produce platform specific solutions, just the open GPS data for all.
Posted by: James Corbett | April 20, 2006 at 03:01 PM
looking for road map software I can load on my Garmin GPS V with detailed road map of Ireland. I'll be traveling in the southern half of the country and am trying to avoid buying Garmin's world map software. I understand it does not have the detail I need regarding the more rural areas I'll br traveling. Any free ware for a user that needs this capability for a week at the most?
Posted by: Bill | May 01, 2006 at 02:22 AM
Hi Bill, unfortunately I don't know of any such software, sorry :(
Posted by: James Corbett | May 02, 2006 at 09:48 AM