Spaced Out ::

Following on from my last blog, I spent a little time this week trying to extract data from the Garmin Geko’s so that I could load the tracklogs over standard OS basemap data. I was interested to see if there was a relatively painless open-source route and, after a bit of digging, came across GPSBabel. This is primarily a GPS data convertor, but also allows you to pull data straight off a unit. One command line later I had a GPX file (standard XML GPS logfile) of my data and was wondering how I could get this easily in to ArcGIS. Well, GPX2SHP came to the rescue. One more command line and I had my final shapefile. The shapefile had no coordinate system because GPSBabel had simply pulled off the raw data. Consequently, when it was loaded in to ArcMap it assumed it was Geographic data with a set datum. I wanted to change it to WGS84 and couldn’t see any obvious way to do it. Well, to cut a (very) long story short you need to use ArcCatalog and then right click on theshapefile and select properties. I had already looked here, however the somewhat counter-intuitive solution is to click on the Fields tab, select the Shapefield and then click on the “…” button next to “Spatial Reference”. This brings up the standard window for selecting a coordinate system and any changes can be made. However it couldn’t have been hidden any better without a lot more effort!!!!

End result: a nice tracklog that can be used within ArcMap.