Google Earth Engine（GEE）——计算ndvi的零星植被状况（墨西哥为例）

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本文使用Landsat7影像来计算ndvi的零星植被状况并查看影像的温度，这里面要特别注意不同的影像集合中波段名称是不同的，所以建议要认真查看波段，这里再次列举一下本次要用到的影像波段，特别注意去云波段：

Resolution

30 meters

Bands Table

Name	Description	Min	Max	Units	Wavelength	Scale	Offset
SR_B1	Band 1 (blue) surface reflectance	1	65455		0.45-0.52 μm	0.0000275	-0.2
SR_B2	Band 2 (green) surface reflectance	1	65455		0.52-0.60 μm	0.0000275	-0.2
SR_B3	Band 3 (red) surface reflectance	1	65455		0.63-0.69 μm	0.0000275	-0.2
SR_B4	Band 4 (near infrared) surface reflectance	1	65455		0.77-0.90 μm	0.0000275	-0.2
SR_B5	Band 5 (shortwave infrared 1) surface reflectance	1	65455		1.55-1.75 μm	0.0000275	-0.2
SR_B7	Band 7 (shortwave infrared 2) surface reflectance	1	65455		2.08-2.35 μm	0.0000275	-0.2
SR_ATMOS_OPACITY	A general interpretation of atmospheric opacity generated by LEDAPS and based on the radiance viewed over Dark Dense Vegetation (DDV) within the scene. A general interpretation of atmospheric opacity is that values (after scaling by 0.001 is applied) less than 0.1 are clear, 0.1-0.3 are average, and values greater than 0.3 indicate haze or other cloud situations. SR values from pixels with high atmospheric opacity will be less reliable, especially under high solar zenith angle conditions. The SR_ATMOS_OPACITY band is provided for advanced users and for product quality assessment and has not been validated. Most users are advised to instead use the QA_PIXEL band information for cloud discrimination.	0	10000			0.001	0
SR_CLOUD_QA	Cloud Quality Assessment					0	0
SR_CLOUD_QA Bitmask	Bit 0: Dark Dense Vegetation (DDV) Bit 1: Cloud Bit 2: Cloud Shadow Bit 3: Adjacent to Cloud Bit 4: Snow Bit 5: Water
ST_B6	Band 6 surface temperature. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	65535	Kelvin	10.40-12.50 μm	0.00341802	149
ST_ATRAN	Atmospheric Transmittance. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	10000			0.0001	0
ST_CDIST	Pixel distance to cloud. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	24000	km		0.01	0
ST_DRAD	Downwelled Radiance. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	28000	W/(m^2*sr*um)/ DN		0.001	0
ST_EMIS	Emissivity estimated from ASTER GED. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	10000			0.0001	0
ST_EMSD	Emissivity standard deviation. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	10000			0.0001	0
ST_QA	Uncertainty of the Surface Temperature band. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	32767	K		0.01	0
ST_TRAD	Thermal band converted to radiance. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	22000	W/(m^2*sr*um)/ DN		0.001	0
ST_URAD	Upwelled Radiance. If 'PROCESSING_LEVEL' is set to 'L2SR', this band is fully masked out.	0	28000	W/(m^2*sr*um)/ DN		0.001	0
QA_PIXEL	Pixel quality attributes generated from the CFMASK algorithm.					0	0
QA_PIXEL Bitmask	Bit 0: Fill Bit 1: Dilated Cloud Bit 2: Unused Bit 3: Cloud Bit 4: Cloud Shadow Bit 5: Snow Bit 6: Clear 0: Cloud or Dilated Cloud bits are set 1: Cloud and Dilated Cloud bits are not set Bit 7: Water Bits 8-9: Cloud Confidence 0: None 1: Low 2: Medium 3: High Bits 10-11: Cloud Shadow Confidence 0: None 1: Low 2: Medium 3: High Bits 12-13: Snow/Ice Confidence 0: None 1: Low 2: Medium 3: High Bits 14-15: Cirrus Confidence 0: None 1: Low 2: Medium 3: High
QA_RADSAT	Radiometric saturation QA					0	0
QA_RADSAT Bitmask	Bit 0: Band 1 data saturated Bit 1: Band 2 data saturated Bit 2: Band 3 data saturated Bit 3: Band 4 data saturated Bit 4: Band 5 data saturated Bit 5: Band 6L data saturated Bit 6: Band 7 data saturated Bit 7: Unused Bit 8: Band 6H data saturated Bit 9: Dropped pixel 0: Pixel present 1: Detector doesn't have a value

代码：

获取的最大最小值的结果： 这里用的是.values().get(0),也就是第一个值

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结果：

​代码链接：

(179条消息) Google Earth Engine（GEE）——计算ndvi的零星植被状况（墨西哥为例）_此星光明2021年博客之星云计算Top3的博客-CSDN博客

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