Trend Surface Analysis
Comparing Different Orders of Polynomials
The impact on changing the order of the polynomial used for the trend surface analysis can easily be seen when maps of the same variable with different orders of polynomials are compared. The 1st order polynomial map is very simplistic, with the the clast size increasing towards the southeast. The 2nd order polynomial shows that the areas with the highest D50 values are found in the middle of the map with the size decreasing out towards the edges. The 3rd order polynomial map is the most complex and show that the highest values are found towards the center of the main valley and also towards the northwest (which is the opposite of what the 1st order polynomial map shows). This map also shows that there are higher values near the southwest of the map, which corresponds with the deposits in the South Creek tributary valley. The 4th order polynomial map shows less variation across the area than then 3rd order polynomial map, although, the pattern of high D50 values is quite similar to that of the 3rd order polynomial map.
Trend Surfaces of Other Variables
Based on the fact that the trend surface analysis that was done using a 3rd order polynomial seemed to show the most interesting patterns given the data, the trend surface analysis of the other variables was conducted using 3rd order polynomials as well.
According to the trend surface analysis, the highest clast abundance values are found on the south side of the main valley and to the northwest while the lowest values are found in the southwest, near the South Creek tributary valley (and over the lake).
In general, the C40 index values trend from lowest in the northwest to highest in the southeast. Within the moderate trend surface values, which are located in parallel to the direction of the main valley, there are higher values to southwest (over the lake) and lower values over the actual deposits.
The RA index values follow a similar trend as the C40 index values, trending from low values in the northwest to higher values in the southeast, with some variation in the moderate values in the middle. Like the C40 index trend surface, there is a peak over the lake in the southwest corner of the map, however on the RA index map, this area of higher values stretches up further to the northeast than is found on the C40 index trend surface map.
The highest values of vegetation density are found on the east side of the map and there are two peaks on the trend surface, one to the southwest, near the South Creek tributary valley and the other over the center of the main valley (although the trend surface values do reach a maximum at the eastern edge of the trend surface).
According to the trend surface analysis, the highest clast abundance values are found on the south side of the main valley and to the northwest while the lowest values are found in the southwest, near the South Creek tributary valley (and over the lake).
In general, the C40 index values trend from lowest in the northwest to highest in the southeast. Within the moderate trend surface values, which are located in parallel to the direction of the main valley, there are higher values to southwest (over the lake) and lower values over the actual deposits.
The RA index values follow a similar trend as the C40 index values, trending from low values in the northwest to higher values in the southeast, with some variation in the moderate values in the middle. Like the C40 index trend surface, there is a peak over the lake in the southwest corner of the map, however on the RA index map, this area of higher values stretches up further to the northeast than is found on the C40 index trend surface map.
The highest values of vegetation density are found on the east side of the map and there are two peaks on the trend surface, one to the southwest, near the South Creek tributary valley and the other over the center of the main valley (although the trend surface values do reach a maximum at the eastern edge of the trend surface).