Water (WA) | Impervious Surface (IS) | Non-Tree Vegetation (NTV) | Tree Canopy (TC) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Land cover (weighted mean of all sample size schemes) | 1.0% | 38.2% | 45.8% | 14.7% |
Sample size schemea | 10 points (2.8/km2) | 12 points (3.3/km2) | 25 points (6.9/km2) | 50 points (13.9/km2) | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Land cover | WA | IS | NTV | TC | WA | IS | NTV | TC | WA | IS | NTV | TC | WA | IS | NTV | TC |
Minb (%) | 0.0 | 10.0 | 30.0 | 0.0 | 0.0 | 16.7 | 25.0 | 8.3 | 0.0 | 20.0 | 36.0 | 4.0 | 0.0 | 32.0 | 34.0 | 10.0 |
Meanb (%) | 0.0 | 36.0 | 45.0 | 18.0 | 0.8 | 31.7 | 50.0 | 17.1 | 0.8 | 41.2* | 45.2 | 12.8 | 0.8 | 42.2*** | 43.0 | 14.0 |
Maxb (%) | 0.0 | 60.0 | 80.0 | 40.0 | 8.3 | 50.0 | 75.0 | 41.7 | 4.0 | 56.0 | 64.0 | 28.0 | 2.0 | 52.0 | 52.0 | 22.0 |
SDc | 0.0 | 16.5 | 19.0 | 12.3 | 2.6 | 10.2 | 14.0 | 10.3 | 1.7 | 11.3 | 8.9 | 7.5 | 1.0 | 6.1 | 5.8 | 4.2 |
CVc | 0.0 | 45.7 | 42.2 | 68.3 | 0.0 | 32.4 | 29.1 | 61.3 | 210.8 | 27.5 | 19.6 | 58.6 | 129.1 | 14.4 | 13.6 | 30.2 |
Sample size schemea | 100 points (27.8/km2) | 250 points (69.4/km2) | 500 points (138.9/km2) | 1,000 points (277.8/km2) | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Land cover | WA | IS | NTV | TC | WA | IS | NTV | TC | WA | IS | NTV | TC | WA | IS | NTV | TC |
Min (%) | 0.0 | 25.0 | 36.0 | 9.0 | 0.4 | 35.2 | 42.8 | 11.6 | 0.0 | 34.4 | 43.8 | 12.4 | 0.7 | 36.5 | 42.9 | 13.4 |
Mean (%) | 0.0 | 36.0* | 48.0 | 14.0 | 1.0 | 38.8*** | 45.8 | 14.4* | 0.9 | 38.4*** | 46.3 | 14.5** | 1.1 | 38.0*** | 45.4 | 14.9** |
Max (%) | 3.0 | 46.0 | 62.0 | 18.0 | 2.0 | 42.0 | 47.6 | 16.4 | 1.4 | 41.8 | 50.0 | 17.2 | 1.8 | 40.4 | 47.2 | 15.8 |
SD | 1.0 | 6.1 | 7.6 | 2.5 | 0.5 | 2.4 | 1.7 | 1.8 | 0.4 | 2.0 | 1.8 | 1.3 | 0.3 | 1.3 | 1.2 | 0.9 |
CV | 161.0 | 16.9 | 15.5 | 17.8 | 54.2 | 6.2 | 3.7 | 12.6 | 51.5 | 5.2 | 3.9 | 9.0 | 29.2 | 3.4 | 2.7 | 6.0 |
↵a Shown are the number of sample points (N) and the sampling intensity (N per km2 of study area).
↵bMinimum, mean, and maximum run values derived from ten independently replicated runs of i-Tree Canopy for each sample size scheme.
↵cSD (sample standard deviation) and CV (coefficient of variation: mean ÷ std. dev. × 100) of the ten replicates for each sample size scheme.
Asterisks (*) indicate a significant difference between the mean land cover values of a given sample size scheme and the land cover values derived from a computerized classification of high-resolution imagery (shown in Table 2) using one-sample t-tests (*p < 0.05; **p < 0.01; *** p < 0.001).