Lab--How Long is the Path Atop the Cliff?
Whitby is a historic
fishing town on the coast of North Yorkshire in England. We
have the following data:
New DEM DTMs at 0.5, 1, and 2 m
resolution from the
UK Ordnance Survey.
New DEM DSMs
at 0.5, 1, and 2 m resolution from the
UK Ordnance Survey.
Database. GPS log for part of a hike taken
along the coast. This averages about 10 second spacing between
readings. It has the time, Lat, Long, speed, and heading from the GPS.
To digitize the route, you will use two procedures. We want a
sequential point database, with the points in order. You should plot the
GPS log using the Connect
sequential points option to provide a map upon which to digitize.
- Stream Digitization:
- Point mode digitization:
Database with the route, either digitized or imported from GPS/phone
- Add elevations, Edit: DEM, Add
interpolated elevation from DEM
- Add slope: Edit: DEM, Add slope/aspect from DEM.
This will be the slope at the point, and not necessarily the component in
the direction of travel.
- Add travel information: Edit,
Navigation, Add travel path (Azimuth, distance, speed).
Insure you select interval distances, cumulative distances, and 3D
distances.
- You can sum the fields by Double clicking on field name
and picking Sum.
Tools you might consider
Deliverables:
- Complete the table below:
DEM |
DEM Size |
Track |
Distance |
3D distance |
Gain |
Drop |
50 cm DTM |
|
GPS logger |
|
|
|
|
1 m DTM |
|
GPS logger |
|
|
|
|
2 m DTM |
|
GPS logger |
|
|
|
|
50 cm DTM |
|
GPS logger |
|
|
|
|
1 m DTM |
|
GPS logger |
|
|
|
|
2 m DTM |
|
GPS logger |
|
|
|
|
"Best" choice |
|
Your stream digistization |
|
|
|
|
"Best" choice |
|
Your point mode digitization |
|
|
|
|
- Discuss which digitization mode you prefer. Consider both how hard
it was to do, and how well your results for the distances compare with the
database produced by the GPS.
- Discuss how much you think the 50 cm DEM improves results compared with
the 1 and 2 m data sets.
- Where are the biggest DZ values between successive readings? Is
there anything there that might account for the readings?
- For computing the distances and elevation changes, is the DTM or the DSM
better? Why?
- For terrain visualization while hiking or doing your analysis, is the
DTM or the DSM better? Why? Consider the
openness, reverse
grayscale slope, and reflectance maps, and show three distinct types of
terrain and how you recognized them.
- What are the features at the following locations? (You might want
to consult additional sources, and consider their size.)
- 54.48540197,-0.59528116
- 54.48655703,-0.59230511
- 54.47650072,-0.58461403
Last revision 3/27/2017