CTC Bootcamp Assignment 5 - Creating Topo Trails and Generating Elevation Profiles

Tuesday, March 17, 2015

After we got soaked into contour lines and topomaps let us try creating some new trails using terrain maps and check out elevation profiles.

Assignment 5

Type: home assignment
Date: Wed Mar 4th
Deadline: Sat Mar 7th
Duration: 1-2 hours
Submit one set of answers per team
All team members to participate & understand

Creating a Trail

In assignment #2 you identified existing trails in the satellite view in Google Earth
Let us know create some trails using the terrain view in Google Maps
Open maps.google.com in your browser
Click in the search box and Choose "My Maps":

The Google Maps Engine will be started allowing you to create trails and waypoints on top of the any map view (roads, satellite, terrain)
Give a nice name to your map, e.g. "My first hill trail"
Search for "Chengalpattu"
Click on Base Map and choose "Terrain" to bring up a topographic view of the area

Now create a new trail (use "Draw a Line" tool on top) that starts from GST, proceed East into valley, climb up on the South ridge to the 200m peak, climb down along the Northern ridge to the 100m Saddle and proceed Northeast to the 120m North peak to finish at the main road.
Next create a few waypoints (use "Add Marker" tool on top) along this trail: GST road, 200m peak, saddle between both peaks, 120m peak, main road - shown by red balloon markers below:

Exporting a Trail

Next, export your trail and waypoints to a KML file by clicking on the three vertical dots menu as shown below:

Open the KML file in Google Earth to view your newly created trail on the Satellite View
By default you ll be looking from straight up (2D kind of view). Use the top-right tool to:
  • Tilt the view and get a lower viewing angle (click continuously on the up arrow)
  • Rotate the view - see your trail from different directions (click the N symbol and drag it left-right)
  • Use the roller on your mouse to zoom in/out to the map

This will give you a more 3-dimensional view/feeling on the area. Play around with these 3 options to get a full 3D view from all perspectives on your trail.

Elevation Profile

Right click on your trail and choose "Show Elevation Profile"
You know get an excellent view of the slope, ascends and descends along the trail. 
Move your mouse across the elevation profile to see the exact location and altitude of each point along the trail - the central peak appears to be 217m
The Southern ridge of the central peak is much more gradual as shown by the wider spaced contour lines above and the gradual slope (left) in the elevation profile below
The Northern side of the central peak is more steep as shown by the narrow spaced contour lines above and the steeper slope (right) in the elevation profile below

Ensure to go through all above steps yourself (not just read this email) to get familiar with the tools and concepts.
You should be able to correlate the terrain view (contour lines) with the elevation profile above

Assignment - do it yourself!

Now that we created a new trail on a topographic map (rather then tracing an existing trail in Satellite view) using Google Maps Engine and seen the 3D view/elevation profile in Google Earth let's try it ourselves!

Identify a small set of hills near your area/city (different from Chengalpattu range) and go through the same steps above. This is the typical routine any CTC organizer follows to create a new trekking trail through the mountains: identify a sequence of (not too steep) ridges and valleys connecting peaks and saddles to create a new trail for exploration. The exported KMZ file can be downloaded in your smartphone for navigation during the trek. Simple as that! ;-)

Submit a (1) screenshot of your trail on Google Maps terrain view and (2) 3D view in Google Earth with Elevation profile (similar as above) in this answer form.

Get ready next for some hands-on with compass, bearing and positioning good old style (without GPS)!



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