Tracking Creatures of Bavarian Folklore Using a Least-Cost Path Model

Table of Contents

  1. Tracking Creatures of Bavarian Folklore Using a Least-Cost Path Model
  2. Setting up Your Workspace
  3. Preparing the Data
  4. Skill Drill: Geocoding an Address and Creating a CSV Table to Import As XY Data
  5. Skill Drill: Defining the Study Area
  6. Skill Drill: Acquire Elevation Data from the USGS National Map Viewer
  7. Skill Drill: Acquire Land Cover Data from the USGS National Map Viewer
  8. Skill Drill: Acquire Hydrography Data from the USGS National Map Viewer
  9. Changing Global Environment Settings for Raster Processing
  10. Creating Cost Surface Models Using a Relative Cost Scale
  11. Creating a Remap Table to Reclassify Elevation
  12. Skill Drill: Creating a Remap Table to Reclassify Slope
  13. Skill Drill: Creating a Remap Table to Reclassify Tree Canopy Density
  14. Converting the Hydrography Features to Cost Surface Models
  15. Creating a Total Cost Surface Model
  16. Creating a Cost-Distance Surface Model
  17. Creating a Migration Corridor
  18. Determining the Least-Cost Path
  19. Skill Drill: Creating a Map of the Results

Preparing the Data

The following Skill Drills for preparing the data use the knowledge you have learned in previous courses, including Geospatial Concepts (GSP 101) and Geographic Information Science (GSP 270). Therefore, the instructions do not contain many step-by-step details. You should refer to previous coursework if needed. Registered students may also post questions on the weekly Q&A Discussion Forum on the Canvas LMS.

Skill Drill: Adding the Den Locations as XY Data

In this scenario, HSU students recorded the location of several wolpertinger dens using hand-held GPS receivers. Information about these dens, including location and the identification number, is available in a comma-separated value (CSV) file.

If you are a registered student at Humboldt State University, you may access the data used in this lab by logging into the course using the Canvas LMS. Find the link to download the data on the assignment page in Canvas. Download and then decompress the file into your original folder.

A GPS receiver set to WGS 1984 was used to obtain the geographic coordinates in decimal degrees. It’s important to remember that each geodetic datum as a unique set of latitude and longitude values. For example, the latitude and longitude values for your home using the North American Datum of 1983 will be different than the latitude and longitude values using the North American Datum of 1927. Likewise, the World Geodetic Datum of 1984 (WGS 1984) will use yet another set of latitude and longitude values to define the location of your home. Like most latitude and longitude values, you will obtain from the internet or a GPS receiver, the decimal degrees in this are currently in the geographic spatial reference system WGS 1984. When adding XY data, the ArcGIS software only reads the decimal degrees. It is unaware to which spatial reference system these decimal degree values belong. ArcMap will assume, incorrectly, that the spatial reference is the same as the dataframe. You must indicate in the Add XY data dialog box that this series of decimal degree values belong to the WGS 1984 spatial reference system. If you do not, your den locations will likely end up somewhere in the ocean.

An image of the Add XY data dialog box
You can locate the spatial reference ArcMap will use under the Description. To re-define the spatial reference, click on the Edit button to select the correct spatial reference.

After adding XY data, the ArcGIS software will create a temporary events layer. In many ways, the events layer appears to be similar to a shapefile. However, it is only a temporary representation and does not have an associated database.

An image of the Warning Dialog Box in ArcMap.
The ArcGIS software will remind you that you will still need to export the events layer to create a permanent shapefile that includes database functionality.

Export the events layer as a shapefile and save it to your working folder. You should now have a shapefile of the den locations in the WGS 1984 spatial reference system saved in your working folder. Next use the Project tool to create a copy of the data with the NAD 83 UTM Zone 10 spatial reference system. Add the layer with the correct spatial reference to your Table of Contents and remove the old version.

An image of the ArcMap window showing den locations.
An events layer is temporary and should be exported as a shapefile. In this map, the Del Norte and Humboldt County boundaries were added in the background as a frame of reference. These background layers are not needed for the analysis. They were obtained from the U.S. Census Bureau.