Tuesday, January 25, 2011

Why Parking Aisles are a Good Thing

I have been mapping parking aisles in my neighborhood. I was hoping that someday some OSM-based routing engines would tell me where I could take a short cut on my bike or on foot that would take me through the parking aisles and foot paths rather than around the parking lot.

I found such a situation in my neighborhood today at the Table Mesa Mall. You can see that I have added parking lot, parking aisles (not very straight but I will clean them up), buildings, shops and even stairs.

My scenario is that I am leaving King Soopers grocer on the west side of the complex and want to travel to Savers on the east side. I put the query to both open.mapquest.com (which uses OSM data) and maps.google.com (which uses data from somewhere else). Open.Mapquest sends me via the shortest route through the parking lot... Google sends me around the periphery.

Clearly, as Google gets more data into their dataset, their routing will likely get better... but that's the point, isn't it... that OSM also didn't have the data but then I came along and added it... and then MapQuest took that vector data and updated their routing web service.

Go OSM!!! Good job MapQuest!!!

Here are the two results (you can click on the image to get a larger view)...

Wednesday, January 5, 2011

OpenStreetMap Survey using iPad and GaiaGPS

There are many good OSM mapping techniques described at http://wiki.openstreetmap.org/wiki/Mapping_techniques.

The ideal mapping approach involves having tools that let you record new features (e.g., GPS and some kind of note taking device such as pen and paper) and also let you see what has already been mapped in your survey area (e.g., Walking Papers).

I prefer to use as little paper as possible, so when I discovered this solution that works for GPS-enabled iPad or iPhone devices, I wanted to share it.

You will need to download GaiaGPS (http://www.gaiagps.com/) from the iTunes App Store. Once you have installed the application, you can download the current OSM maptiles for the area you want to survey and then you can go into the field and start your work. As you start your surveying, you can place pins (aka Waypoints) and label them with notes relevant to the feature you are capturing. If find labelling/annotating waypoints in GaiaGPS orders of magnitude easier than trying to do the same thing with a standard GPS unit. You may also want to consider turning on a track (GaiaGPS calls it a "trip") so that you can get the path of your survey for later upload to OSM.

Once you have finished your survey, you can get the .gpx data out of GaiaGPS by e-mailing it to yourself. Once on your desktop, you can import the .gpx data with annotated waypoints and tracks into a tool like JOSM to guide you in adding OSM features.

Here is a 5 minute video that demonstrates the key points. The video quality is mediocre but you should get the idea of how to use the tool. I am not a representative of TrailBehind (the makers of GaiaGPS). I am only a very satisfied customer that has learned to use this app to simplify my OSM surveys.

Sunday, January 2, 2011

Viewing OSM tiles using an iOS 4.2 device

I have not been able to get the slippymap used by sites like http://www.openstreetmap.org to play well with my iPad.  The slippymap provided by OpenLayers doesn't seem to recognize the touch gestures for zooming and panning.  I noticed, however, that the Google Maps API does recognize the touch gestures.  So when I saw in "OpenStreetMap: Using and Enhancing the Free Map of the World" the example to load OSM tiles into the GMaps API, I thought I would give it a try.

You can see the results here.  Nothing special, but now at least I can navigate the OSM data easily with my iPad.  The example I am using makes use of tiles that I am building for a bicycle route map of Boulder, CO, USA.  It is my first rendering project and I am using Maperitive for it.  I will post more on that later.