# 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.

Database with the route, either digitized or imported from GPS/phone

• 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