packages_gee/fstats at main · BzGEO/packages_gee · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
/* Estimate forest cover percentage using MODIS data
 */

function fstat_modis(img,res,aoi,year) {

var f_stat = ee.Number(img.clip(aoi).select('constant').eq(1).multiply(ee.Image.pixelArea()).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.sum(),
  scale: res,
  maxPixels: 1e18
}).get('constant')).divide(1000000);

var for_pct = ee.Number(img.clip(aoi).select('constant').eq(1).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.mean(),
  scale: res,
  maxPixels: 1e18
}).get('constant')).multiply(100);

var nf_pct = ee.Number(img.clip(aoi).select('constant').eq(0).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.mean(),
  scale: res,
  maxPixels: 1e18
}).get('constant')).multiply(100);

print('MODIS, year: ', year);
print('est. forest area: ', f_stat, 'sq. km');
print('est. % forest cover: ', for_pct, 'percent');
print('est. % non-forest cover: ', nf_pct, 'percent');

}

exports.fstat_modis = fstat_modis;

////////////////////////////////////////////////////////////////////////////////////////////////

function fstat_modis_(img,res,aoi, year) {

var f_stat = ee.Number(img.clip(aoi).select('canopy_cover').eq(1).multiply(ee.Image.pixelArea()).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.sum(),
  scale: res,
  maxPixels: 1e18
}).get('canopy_cover')).divide(1000000);

var for_pct = ee.Number(img.clip(aoi).select('canopy_cover').eq(1).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.mean(),
  scale: res,
  maxPixels: 1e18
}).get('canopy_cover')).multiply(100);

var nf_pct = ee.Number(img.clip(aoi).select('canopy_cover').eq(0).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.mean(),
  scale: res,
  maxPixels: 1e18
}).get('canopy_cover')).multiply(100);

print('MODIS, year: ', year);
print('est. forest area: ', f_stat, 'sq. km');
print('est. % forest cover: ', for_pct, 'percent');
print('est. % non-forest cover: ', nf_pct, 'percent');

}

exports.fstat_modis_ = fstat_modis_;

////////////////////////////////////////////////////////////////////////////////////////////////

/***
 * Estimate forest cover percentage using Landsat data
 */

function fstat_landsat(img, res, aoi, year) {

var f_stat = ee.Number(img.clip(aoi).select('constant').eq(1).multiply(ee.Image.pixelArea()).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.sum(),
  scale: res,
  maxPixels: 1e18
}).get('constant')).divide(1000000);

var for_pct = ee.Number(img.clip(aoi).select('constant').eq(1).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.mean(),
  scale: res,
  maxPixels: 1e18
}).get('constant')).multiply(100);

var nf_pct = ee.Number(img.clip(aoi).select('constant').eq(0).reduceRegion({
  geometry: aoi.geometry(),
  reducer: ee.Reducer.mean(),
  scale: res,
  maxPixels: 1e18
}).get('constant')).multiply(100);

print('Landsat, year: ', year);
print('est. forest area: ', f_stat, 'sq. km');
print('est. % forest cover: ', for_pct, 'percent');
print('est. % non-forest cover: ', nf_pct, 'percent');

}

exports.fstat_landsat = fstat_landsat;

//////////////////////////////////////////////////////////////////////////////////////////////////////////