Module 6: Corridor Analysis

 Module 6: Corridor Analysis

In this weeks module we learned how to do corridor analysis, which considers a range of possible paths instead of a single optimal path. This is useful because the least-cost path is not always the most optimal path for what a person needs for the area. In scenario 4 we once again needed to do the conceptual steps before starting out analysis.

Step 1: State the Problem

Problem: Potential movement of black bears between the two protected national forest areas.

Goal: Create a suitability and corridor analysis of the black bear movement between the national forests.

Step 2: Break Down the Problem

Objective 1: Reclassify the roads into suitability classes.

Input dataset: Roads shapefile

Objective 2: Reclassify the slopes into suitability classes.

Input dataset: Elevation raster

Objective 3: Reclassify the Land cover into suitability classes.

Input dataset: Land cover raster

Objective 4: Invert suitability model

Input dataset: The reclassification models of the roads, elevation, and land cover.

Objective 5: Create a corridor analysis

Input: The cost path inputs for the two national forests.

Step 3: Explore Input Datasets

Once again this is from Model Builder within ArcGIS Pro which is helpful because it can do all the data for you without doing each step separately. Also, it lets you work through the problem before beginning the work. The image below is my flowchart for this scenario.

When I did the analysis, I did the corridor analysis. I made sure to get the least-cost path for both national forest polygons. First, I did the cost distance and cost path for both of the polygons. After changing the least-cost path to a polyline I then did the corridor analysis from Scenario 3. I used the corridor tool where I put in the two cost distance surfaces and inputs. There is no graduated color ramp, so I went to classify and switched it to three breaks and added in the threshold for each one. Similar to scenario 3 I times the minimum value by 1.05, 1.1, and 1.15. This showed the different areas and how they were less optimal as you went out. The image below shows the corridor analysis of the best path between the two national forests based on the criteria that was given to us in the beginning of the distance to the roads, elevation, and land cover.

When thinking about the data after the initial analysis there are more factors that I would see if we could get more information. First, I would possibly see if there were any criteria for the rivers in the area and what the black bears might want to be close to those areas as well. Another factor would be if there were any developments in the area that could disturb the bears and where they might want to go with the corridor analysis.

This scenario did have a couple of hiccups on trying to get the data to represent the best paths. Even though I did all the analysis correct I was only able to get one corridor analysis path. I tried different ways but it was only giving me one route each time. I am not sure the best way to fix this, but when doing the exercise it did say the Cost Distance, Cost Path, and Corridor Tools were being taken out and replaced with a newer one. This might help with getting the correct analysis in the future. At the same time, it is important to note that when doing the analysis it is important to take your time and try to understand what you are doing for each step. Lastly, make sure to name your outputs to where you can see which features are being represented and not to use the same name within the same geodatabase.