Continuing on the mapping theme, I wanted to talk about a few tools I use for my mapping activities.
I use an old Garmin eTrex Legend GPS receiver for my geocaching hobby and backwoods exploration. I purchased Garmin’s MapSource Topo in 2004, and I still use it today. The software isn’t updated much anymore, but it reliably moves waypoint and track data to and from my receiver. My map database is still original, but it isn’t a big issue as I don’t tend to use the unit for street navigation. I usually save “raw” field data in .gdb files, and also save a copy where I’ve cleaned up the tracks or edited waypoint symbology and labels. These files can be converted / imported into the programs below.
Google Earth Pro
I know most people know about Google Maps in their on-line or phone app form. Fewer people know about the free, downloadable PC/Mac app called Google Earth Pro. In addition to allowing you to view zoom-able maps of the entire globe, you can also make your own maps to share with others. The features I use are:
- Satellite basemaps (recent historical imagery is available)
- Track and waypoint overlays from my collected GPS data
- Photo overlays of old maps and aerials (zoomed and rotated)
- Getting coordinates of features in the overlays and basemaps.
You can also make cool map fly-over videos. It’s an awesome tool and a great place to start learning about making maps.
ArcGIS / ArcMap
Sometimes you need the real deal for mapping. In my case, I found that building a composite aerial map of around 16 photos in Google Earth Pro was bogging down the computer I was using. I also needed to stretch a hand drawn map in a non-uniform way to match the basemap. That task exceeded the capabilities of Google Earth Pro’s zoom and rotate (AKA affine transformation).
Esri’s ArcGIS / ArcMap does all of this work very well. It’s not so easy for casual users without mapping experience, but it’s definitely the way to go for people who are really into this stuff. It lets you stretch maps and aerial images to fit other maps (georeferencing) and uses variable image resolution to speed screen update time. This is the tool that makes most of the print maps you see today. I’ve completed a lot of on Esri’s on-line courses. It’s the next best thing to community college courses on the subject. I find learning this tool to be quite engaging, especially when paired with my interest in local history.
QGIS is another fantastic Geographical Information System program. It’s open source and free to use. It has many of the features of ArcGIS and its components. I did have great success in using the program to get beyond my issues in assembling the previously mentioned composite. On-line training is also readily available. I stopped using the program when I decided to start learning the more mainstream ArcGIS.