Table 3.
PPV (%) of approximation methods versus map-based measures for sample areas in Aberdeenshire and Ayrshire
| |
|
Current method |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| All premises <1 km point distance | All premises <3 km point distance | All premises <5 km point distance | All premises <26 m field distance | All premises <151 m field distance | All premises <1 km field distance | By Voronoi tessellation | By area weighted tessellation | ||
|
Aberdeenshire |
|
|
|
|
|
|
|
|
|
|
Gold standard |
All <15 m |
65.2 |
22.7 |
10.4 |
93.9 |
85.0 |
37.4 |
38.1 |
36.4 |
|
All <15 m - river |
62.3 |
21.4 |
9.9 |
87.7 |
79.4 |
35.0 |
35.7 |
34.1 |
|
|
All <15 m - road |
55.1 |
19.6 |
8.9 |
79.8 |
72.2 |
31.8 |
32.3 |
31.2 |
|
|
All <15 m - river/road |
52.2 |
18.3 |
8.3 |
73.6 |
66.7 |
29.3 |
29.9 |
28.9 |
|
|
All <15 m - river/road/ditch |
49.3 |
16.5 |
7.5 |
66.9 |
60.6 |
26.7 |
26.9 |
26.3 |
|
|
All <15 m - river/ditch |
59.4 |
18.9 |
8.8 |
78.5 |
71.1 |
31.3 |
31.6 |
30.6 |
|
|
Shared fence |
52.2 |
18.4 |
8.4 |
74.8 |
67.8 |
29.8 |
31.3 |
29.8 |
|
|
Shared fence - river |
50.7 |
17.8 |
8.1 |
72.4 |
65.6 |
28.9 |
29.9 |
28.6 |
|
| |
Shared fence - river/ditch |
49.3 |
16.2 |
7.4 |
66.3 |
60.0 |
26.4 |
27.2 |
26.3 |
|
Ayrshire |
|
|
|
|
|
|
|
|
|
| Gold standard |
All <15 m |
56.7 |
17.2 |
7.4 |
96.1 |
80.4 |
32.0 |
41.2 |
39.1 |
|
All <15 m - river |
53.2 |
15.8 |
6.8 |
89.0 |
74.4 |
29.6 |
38.0 |
36.1 |
|
|
All <15 m - road |
48.3 |
15.0 |
6.4 |
82.9 |
69.3 |
27.5 |
36.5 |
34.6 |
|
|
All <15 m - river/road |
44.8 |
13.6 |
5.9 |
75.7 |
63.3 |
25.2 |
33.3 |
31.6 |
|
|
All <15 m - river/road/ditch |
43.8 |
12.4 |
5.3 |
68.5 |
57.3 |
22.8 |
30.4 |
28.5 |
|
|
All <15 m - river/ditch |
52.2 |
14.5 |
6.3 |
81.5 |
68.1 |
27.1 |
35.2 |
33.1 |
|
|
Shared fence |
46.3 |
14.1 |
6.0 |
78.2 |
65.4 |
26.0 |
33.5 |
31.9 |
|
|
Shared fence - river |
44.3 |
13.1 |
5.7 |
73.5 |
61.4 |
24.4 |
31.8 |
30.2 |
|
| Shared fence - river/ditch | 43.3 | 12.0 | 5.2 | 66.9 | 55.9 | 22.2 | 29.3 | 27.5 | |