Effects of Sampling Interval on Spatial Analysis of Watershed Nitrogen Loading

1
Effects of Sampling Interval on Spatial Analysis
of Watershed Nitrogen Loading

• Derek Wu
• Lynn Usery
• Michael Finn
• U.S. Geological Survey

2
Introduction
Agricultural Non-Point Source (AGNPS) pollution
model
3
Materials and Methods

• Study Area 12 35 km

• Methods
• Simulate a 30-m nitrogen surface
• Take samples of 30, 60, 90, , 600-m intervals
• Calculate mean, standard deviation
• variogram, interpolation accuracy
• clustering level, hot spot pattern

4
Results(Mean , Standard Deviation)
5
Results(Variogram)
(g)
(h)
6
Results (Interpolation Accuracy)
7
Results
Hot spot pattern local Getis-OrdStatisticCluster
ing level global Morans Index
8
Discussion

• Interpolation error Clustering level Hot
  spot areas
• Variogram of 30-m nitrogen

9
Conclusions
10

• Questions Comments?