Google Earth Engine（GEE）—— 全球生态系统动态调查（GEDI）综合数据集（高程、森林覆盖、城市占比）

The Global Ecosystem Dynamics Investigation (GEDI) mission aims to characterize ecosystem structure and dynamics to enable radically improved quantification and understanding of the Earth's carbon cycle and biodiversity. The GEDI instrument, attached to the International Space Station (ISS), collects data globally between 51.6° N and 51.6° S latitudes at the highest resolution and densest sampling of the 3-dimensional structure of the Earth.

GEDI's Level 2A Geolocated Elevation and Height Metrics Product (GEDI02_A) is primarily composed of 100 Relative Height (RH) metrics, which collectively describe the waveform collected by GEDI.

The original GEDI02_A product is a table of point with a spatial resolution (average footprint) of 25 meters. The dataset LARSE/GEDI/GEDI02_A_002_MONTHLY is a raster version of the original GEDI02_A product. The raster images are organized as monthly composites of individual orbits in the corresponding month. Only root-level RH values and their associated quality flags and metadata are preserved as raster bands. Each GEDI02_A_002 raster has 136 bands.

See User Guide for more information.

全球生态系统动态调查（GEDI）任务的目的是描述生态系统的结构和动态，以便从根本上改善对地球碳循环和生物多样性的量化和理解。附属于国际空间站（ISS）的GEDI仪器在全球范围内收集北纬51.6°和南纬51.6°之间的数据，对地球的三维结构进行最高分辨率和最密集的采样。

GEDI的2A级地理位置海拔和高度指标产品（GEDI02_A）主要由100个相对高度（RH）指标组成，它们共同描述了GEDI收集的波形。

原始的GEDI02_A产品是一个点的表格，空间分辨率（平均足迹）为25米。数据集LARSE/GEDI/GEDI02_A_002_MONTHLY是原始GEDI02_A产品的栅格版本。光栅图像被组织为相应月份的单个轨道的月度合成。只有根级相对湿度值及其相关的质量标志和元数据被保留为栅格带。每个GEDI02_A_002栅格有136个波段。

 GEDI L2A Canopy Top Height (Version 2)

Dataset Availability

2019-03-25T00:00:00Z - 2021-09-01T00:00:00

Dataset Provider

NASA GEDI mission, accessed through the USGS LP DAAC Rasterization: Google and USFS Laboratory for Applications of Remote Sensing in Ecology (LARSE)

Earth Engine Snippet

ee.ImageCollection("LARSE/GEDI/GEDI02_A_002_MONTHLY") open_in_new

波段：

Resolution
25 meters

Bands

Name	Description
beam	Beam identifier
degrade_flag	Flag indicating degraded state of pointing and/or positioning information. 3X - ADF CHU solution unavailable (ST-2) 4X - Platform attitude 5X - Poor solution (filter covariance large) 6X - Data outage (platform attitude gap also) 7X - ST 1+2 unavailable (similar boresight FOV) 8X - ST 1+2+3 unavailable 9X - ST 1+2+3 and ISS unavailable X1 - Maneuver X2 - GPS data gap X3 - ST blinding X4 - Other X5 - GPS receiver clock drift X6 - Maneuver & GPS receiver clock drift X7 - GPS data gap & GPS receiver clock drift X8 - ST blinding & GPS receiver clock drift X9 - Other & GPS receiver clock drift
delta_time	Time delta since Jan 1 00:00 2018
digital_elevation_model	TanDEM-X elevation at GEDI footprint location
digital_elevation_model_srtm	STRM elevation at GEDI footprint location
elev_highestreturn	Elevation of highest detected return relative to reference ellipsoid
elev_lowestmode	Elevation of center of lowest mode relative to reference ellipsoid
elevation_bias_flag	Elevations potentially affected by 4bin (~60 cm) ranging error
landsat_treecover	Tree cover in the year 2010, defined as canopy closure for all vegetation taller than 5 m in height as a percentage per output grid cell
landsat_water_persistence	Percent UMD GLAD Landsat observations with classified surface water
lat_highestreturn	Latitude of highest detected return
leaf_off_doy	GEDI 1 km EASE 2.0 grid leaf-off start day-of-year
leaf_off_flag	GEDI 1 km EASE 2.0 grid flag
leaf_on_cycle	Flag that indicates the vegetation growing cycle for leaf-on observations
leaf_on_doy	GEDI 1 km EASE 2.0 grid leaf-on start day-of-year
lon_highestreturn	Longitude of highest detected return
modis_nonvegetated	Percent non-vegetated from MODIS MOD44B V6 data
modis_nonvegetated_sd	Percent non-vegetated standard deviation from MODIS MOD44B V6 data
modis_treecover	Percent tree cover from MODIS MOD44B V6 data
modis_treecover_sd	Percent tree cover standard deviation from MODIS MOD44B V6 data
num_detectedmodes	Number of detected modes in rxwaveform
pft_class	GEDI 1 km EASE 2.0 grid Plant Functional Type (PFT)
quality_flag	Flag indicating likely invalid waveform (1=valid, 0=invalid)
region_class	GEDI 1 km EASE 2.0 grid world continental regions
selected_algorithm	Identifier of algorithm selected as identifying the lowest non-noise mode
selected_mode	Identifier of mode selected as lowest non-noise mode
selected_mode_flag	Flag indicating status of selected_mode
sensitivity	Maxmimum canopy cover that can be penetrated
shot_number	Shot number, a unique identifier. This field is truncated on some images that are being reprocessed to properly show it (as of March 2022). This field has the format of OOOOOBBRRGNNNNNNNN, where: OOOOO: Orbit number BB: Beam number RR: Reserved for future use G: Sub-orbit granule number NNNNNNNN: Shot index
solar_azimuth	Solar azimuth
solar_elevation	Solar elevation
surface_flag	Indicates elev_lowestmode is within 300 m of DEM or MSS
urban_focal_window_size	The focal window size used to calculate urban_proportion
urban_proportion	The percentage proportion of land area within a focal area surrounding each shot that is urban land cover.
rh0	Relative height metrics at 0%
rh1	Relative height metrics at 1%
rh2	Relative height metrics at 2%
rh3	Relative height metrics at 3%
rh4	Relative height metrics at 4%
rh5	Relative height metrics at 5%
rh6	Relative height metrics at 6%
rh7	Relative height metrics at 7%
rh8	Relative height metrics at 8%
rh9	Relative height metrics at 9%
rh10	Relative height metrics at 10%
rh11	Relative height metrics at 11%
rh12	Relative height metrics at 12%
rh13	Relative height metrics at 13%
rh14	Relative height metrics at 14%
rh15	Relative height metrics at 15%
rh16	Relative height metrics at 16%
rh17	Relative height metrics at 17%
rh18	Relative height metrics at 18%
rh19	Relative height metrics at 19%
rh20	Relative height metrics at 20%
rh21	Relative height metrics at 21%
rh22	Relative height metrics at 22%
rh23	Relative height metrics at 23%
rh24	Relative height metrics at 24%
rh25	Relative height metrics at 25%
rh26	Relative height metrics at 26%
rh27	Relative height metrics at 27%
rh28	Relative height metrics at 28%
rh29	Relative height metrics at 29%
rh30	Relative height metrics at 30%
rh31	Relative height metrics at 31%
rh32	Relative height metrics at 32%
rh33	Relative height metrics at 33%
rh34	Relative height metrics at 34%
rh35	Relative height metrics at 35%
rh36	Relative height metrics at 36%
rh37	Relative height metrics at 37%
rh38	Relative height metrics at 38%
rh39	Relative height metrics at 39%
rh40	Relative height metrics at 40%
rh41	Relative height metrics at 41%
rh42	Relative height metrics at 42%
rh43	Relative height metrics at 43%
rh44	Relative height metrics at 44%
rh45	Relative height metrics at 45%
rh46	Relative height metrics at 46%
rh47	Relative height metrics at 47%
rh48	Relative height metrics at 48%
rh49	Relative height metrics at 49%
rh50	Relative height metrics at 50%
rh51	Relative height metrics at 51%
rh52	Relative height metrics at 52%
rh53	Relative height metrics at 53%
rh54	Relative height metrics at 54%
rh55	Relative height metrics at 55%
rh56	Relative height metrics at 56%
rh57	Relative height metrics at 57%
rh58	Relative height metrics at 58%
rh59	Relative height metrics at 59%
rh60	Relative height metrics at 60%
rh61	Relative height metrics at 61%
rh62	Relative height metrics at 62%
rh63	Relative height metrics at 63%
rh64	Relative height metrics at 64%
rh65	Relative height metrics at 65%
rh66	Relative height metrics at 66%
rh67	Relative height metrics at 67%
rh68	Relative height metrics at 68%
rh69	Relative height metrics at 69%
rh70	Relative height metrics at 70%
rh71	Relative height metrics at 71%
rh72	Relative height metrics at 72%
rh73	Relative height metrics at 73%
rh74	Relative height metrics at 74%
rh75	Relative height metrics at 75%
rh76	Relative height metrics at 76%
rh77	Relative height metrics at 77%
rh78	Relative height metrics at 78%
rh79	Relative height metrics at 79%
rh80	Relative height metrics at 80%
rh81	Relative height metrics at 81%
rh82	Relative height metrics at 82%
rh83	Relative height metrics at 83%
rh84	Relative height metrics at 84%
rh85	Relative height metrics at 85%
rh86	Relative height metrics at 86%
rh87	Relative height metrics at 87%
rh88	Relative height metrics at 88%
rh89	Relative height metrics at 89%
rh90	Relative height metrics at 90%
rh91	Relative height metrics at 91%
rh92	Relative height metrics at 92%
rh93	Relative height metrics at 93%
rh94	Relative height metrics at 94%
rh95	Relative height metrics at 95%
rh96	Relative height metrics at 96%
rh97	Relative height metrics at 97%
rh98	Relative height metrics at 98%
rh99	Relative height metrics at 99%
rh100	Relative height metrics at 100%

代码：

var qualityMask = function(im) {
  return im.updateMask(im.select('quality_flag').eq(1))
      .updateMask(im.select('degrade_flag').eq(0));
};
var dataset = ee.ImageCollection('LARSE/GEDI/GEDI02_A_002_MONTHLY')
                  .map(qualityMask)
                  .select('rh98');

var gediVis = {
  min: 1,
  max: 60,
  palette: 'darkred,red,orange,green,darkgreen',
};
Map.setCenter(-74.803466, -9.342209, 10);
Map.addLayer(dataset, gediVis, 'rh98');