Google Earth Engine——Landsat植被連續場（VCF）樹木覆寫層包含了每個30米像素中被高度大于5米的木質植被覆寫的水準地面的百分比估計，資料集來自GFCC表面反射率産品

The Landsat Vegetation Continuous Fields (VCF) tree cover layers contain estimates of the percentage of horizontal ground in each 30-m pixel covered by woody vegetation greater than 5 meters in height. The dataset is available for four epochs centered on the years 2000, 2005, 2010 and 2015. The dataset is derived from the GFCC Surface Reflectance product (GFCC30SR), which is based on enhanced Global Land Survey (GLS) datasets. The GLS datasets are composed of high-resolution Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) images at 30 meter resolution.

Tree cover, the proportional, vertically projected area of vegetation (including leaves, stems, branches, etc.) of woody plants above a given height, affects terrestrial energy and water exchanges, photosynthesis and transpiration, net primary production, and carbon and nutrient fluxes. Tree cover also affects habitat quality and movements of wildlife, residential property value for humans, and other ecosystem services. The continuous classification scheme of the VCF product enables better depiction of land cover gradients than traditional discrete classification schemes. Importantly for detection and monitoring of forest changes (e.g., deforestation and degradation), tree cover provides a measurable attribute upon which to define forest cover and its changes. Changes in tree cover over time can be used to monitor and retrieve site-specific histories of forest change.

The dataset has been produced for four year epochs: 2000, 2005, 2010, and 2015 with an image in the collection for each available WRS2 path/row.

Documentation:

• ​​User's guide​​
• [Algorithm Theoretical Basis Document (ATBD)](​​https://lpdaac.usgs.gov/documents/146/GFCC_ATBD.pdf​​

Provider's Note: Due to the end of NASA MEaSUREs funding, free versions of this dataset are no longer being produced. Interested parties can obtain updated and expanded versions at ​​www.terraPulse.com​​.

Landsat植被連續場（VCF）樹木覆寫層包含了每個30米像素中被高度大于5米的木質植被覆寫的水準地面的百分比估計。該資料集可用于以2000年、2005年、2010年和2015年為中心的四個紀元。該資料集來自GFCC表面反射率産品（GFCC30SR），該産品基于增強的全球土地調查（GLS）資料集。GLS資料集由高分辨率的Landsat 5 Thematic Mapper（TM）和Landsat 7 Enhanced Thematic Mapper Plus（ETM+）圖像組成，分辨率為30米。

樹木覆寫率，即一定高度以上的木本植物的植被（包括葉子、莖、枝條等）的比例、垂直投影面積，影響陸地能量和水的交換、光合作用和蒸騰作用、淨初級生産以及碳和營養物質的通量。樹木覆寫還影響到野生動物的栖息地品質和移動、人類的住宅财産價值以及其他生态系統服務。與傳統的離散分類方案相比，VCF産品的連續分類方案能夠更好地描述土地覆寫梯度。對于檢測和監測森林變化（如森林砍伐和退化）來說，重要的是，樹木覆寫提供了一個可測量的屬性，可以據此定義森林覆寫及其變化。樹木覆寫率随時間的變化可用于監測和檢索特定地點的森林變化曆史。

該資料集為四個年份制作：2000年、2005年、2010年和2015年，每個可用的WRS2路徑/行都有一張圖檔。

檔案。

使用者指南

[算法理論基礎檔案（ATBD）]（https://lpdaac.usgs.gov/documents/146/GFCC_ATBD.pdf

提供者注：由于NASA MEaSUREs資助的結束，該資料集的免費版本已不再制作。有興趣的人可以在www.terraPulse.com，獲得更新和擴充的版本。

Dataset Availability

2000-01-01T00:00:00 - 2015-12-31T00:00:00

Dataset Provider

​​NASA LP DAAC at the USGS EROS Center​​

Collection Snippet

​

​ee.ImageCollection("NASA/MEASURES/GFCC/TC/v3")​

​

Resolution

30 meters

Bands Table

Name	Description	Min	Max	Units
tree_canopy_cover	The percentage of pixel area covered by trees.	100	%
uncertainty	RMSE for tree-canopy_cover
source_index	Identity of source image used for the particular pixel. This is an index into the per image metadata array 'sources'. Only available for 2000, 2005, and 2010.

影像屬性：

Name	Type	Description
path	Double	Path
pathrow	String	Path and row
row	Double	Row
sources	Double	Sources. Only available for 2000, 2005, and 2010.
tree_canopy_cover_class_palette	Double	Tree canopy cover class palette
tree_canopy_cover_class_values	Double	Tree canopy cover class values
year	Double	Year

資料引用：

Paper/Methods Citation: Sexton, J. O., Song, X.-P., Feng, M., Noojipady, P., Anand, A., Huang, C., Kim, D.-H., Collins, K.M., Channan, S., DiMiceli, C., Townshend, J.R.G. (2013). Global, 30-m resolution continuous fields of tree cover: Landsat-based rescaling of MODIS Vegetation Continuous Fields with lidar-based estimates of error. International Journal of Digital Earth, 130321031236007. ​​doi:10.1080/17538947.2013.786146​​.

​​LP DAAC - GFCC30TC​​

var dataset = ee.ImageCollection('NASA/MEASURES/GFCC/TC/v3')
                  .filter(ee.Filter.date('2015-01-01', '2015-12-31'));
var treeCanopyCover = dataset.select('tree_canopy_cover');
var treeCanopyCoverVis = {
  min: 0.0,
  max: 100.0,
  palette: ['ffffff', 'afce56', '5f9c00', '0e6a00', '003800'],
};
Map.setCenter(-88.6, 26.4, 3);
Map.addLayer(treeCanopyCover.mean(), treeCanopyCoverVis, 'Tree Canopy Cover');