Re-Mapping my GPS data

Well, it's been a while, but the SWASC wheels (propeller?) are still turning.

This afternoon I have been discovering how to use a Freeware GIS mapping program called MapWindows. At the moment, it pretty well does all that I need a GIS program to do.

Using GPSBabel, I can import Google Earth data points as a seperate layer. I can export MapWindows shapefiles and directly upload them into Google Earth.

I used Google Earth to export aerial images from my area, then stiched them together. I also recorded 3 Lat/Long points from their map. The three data points where converted to decimal Lat/Long using the following formula:

Example:

Lat: -33 39 37.78 --> -33+(39/60)+(37.78/3600)= -33.66038333

Long: 115 18 24.91 --> 115+(18/60)+(24.91/3600)= 115.3069194

Then using the Georeference tool from within MapWindows and the three decimal Lat/Long. coordinates, I referenced my Google Earth aerial image. The plugin program automatically saved the reference image and the corresponding *.jgw file appending the word '_Rectified' to each of the files. You can then add a new layer and select the now referenced jpg image. MapWindows now knows the Lat/Long coordinates any location on the image.

Next I needed to import my old Sept. 2005 GPS 'walk in the park' Data. As this was stored in a text file, I imported it into Excel, cleaned out some columns that where not going to be used, and saved it as a CSV file. Then, using the CSV import plug-in (needed turning on in the Plug-in Menu), I imported the GPS Data. This is automatically and conveniently added into MapWindow as a new layer. Now I have a lovely map of my walk superimposed on a aerial photo of the neighbourhood. Note one of the differences is that with this method, the shapefile is made up of points, whereas, the MYGPS program I had them showing up a one continueous line.

Interestingly when I had a look, I noticed that I was running back to the house at one time - thinking that the battery might have been dying. Measuring the distance between the dots around the maps my speed varied from 2.59Km/Hr to 14.1Km/Hr. Ok, perhaps the GPS might not be reliable, so I averaged out the data between 6 points, and came up with a nice 9.3Km/Hr.

You can also export the data and import it into Google Earth using the shareware Plug-in called Shape2Earth. This is limited to only 500 data points, but if your really into importing to Google Earth, then this is a Rolls-Royce utility. Otherwise you can use the stand alone Freeware tool called shp2kml. You can then open the *.kml file in Google Earth to see the data points.