转载:http://liangshzh0816.blog.163.com/blog/static/3477676200972383052319/?suggestedreading&wumii
VEGETATION传感器于1998 年3 月由SPOT-4 搭载升空,,从1998年4 月开始接收用于全地植被覆盖观测的SP0T VGT数据。VEGETATION 数据主要由瑞典的Kiruna 地面站负责接收,由位于法国Toulouse的图像质量监控中中负责图像质量并提供相关参数(如定标地数),最终由位于比利时的VITO研究所的图像处理与存档中中负责全地VEGETATION 数据存档与用户定单。
太阳同步圆形近极地轨道轨道高度:832公里
轨道倾角:98.721度
轨道周期:101.469分/圈
重复周期:369圈/26天
降交点时间:上午10:30分
扫描带宽度: 60 公里
两侧侧视:+/-27度 扫描带宽:950公里
spot vgt的几个波段及用途
mainly to perform atmospheric corrections 主要用于大气校正
a red bandcenteredon the absorption peak of the chlorophyll (0.665 ?m),anearinfrared bandcorresponding to themaximumvegetation spectral reflectance and principallyrelated to the structural properties of the canopies and topercentage of soil covered by vegetation,
目前spot VGT数据主要有
vgt d10产品指的是bdc或二向反射合成,这种合成方法是基于二向反射率函数,像元的灰度值为地面反而反射率,海洋地区的反射率设为0,和s10一样有三种合成产品1km 4km和8km
那么mvc和bdc产品有什么区别呢,主要表现在status map 和新增以及去除一些内容
不同产品的数据内容the different planes inthe VEGETATION product
Plane | Description of the plane | File format | Type of product | ||||||
PHYS_VOL | Physical Volumedescriptor | Information about thedelivery | TXT | P/S/D | |||||
LOG | Logical Volume descriptor | Information about | TXT | P/S/D | |||||
RIG | Copyright Descriptor | Information about thecopyright | TXT | P/S/D | |||||
BO | B0 spectral band | Radiometry data | HDF | P/S/D | |||||
B2 | B2 spectral band | Radiometry data | HDF | P/S/D | |||||
B3 | B3 spectral band | Radiometry data | HDF | P/S/D | |||||
MIR | MIR spectral band | Radiometry data | HDF | P/S/D | |||||
NDV | Vegetation Global Index | NDVI indices | HDF | S/D | |||||
SM | Status Map | Data about | HDF | P/S | |||||
Bit NR1: | 0 | 0 | 1 | 1 | |||||
Bit NR 0: | 0 | 1 | 0 | 1 | |||||
clear | shadow | uncertain | cloud | ||||||
BSM | BDC Status Map | Data about Bit NR 7: BRDF model adjustment quality on B0:coded as 0 if bad quality and 1 if good Bit NR 5: BRDFmodel adjustment quality on B3: coded as 0 if bad quality and 1 ifgood Bit NR 1: cloud/shadow or clear: coded as 1 if there iscloud/shadow and 0 if not Bit NR 0 : qrmir: Radiometric quality for MIR coded as 0 if bad and 1 ifgood | HDF | D | |||||
VZA | Viewing zenith angle grid | Data of the satellite zenithangles | HDF | P/S | |||||
VAA | Viewing azimuth anglegrid | Data of the satellite azimuthangles | HDF | P/S | |||||
SZA | Solar zenith angle grid | Data of the solar zenithangles | HDF | P/S | |||||
SAA | Solar azimuth angle grid | Data of the solar azimuthangles | HDF | P/S | |||||
WVG | Water Vapour grid | Data of water vapour | HDF | P | |||||
OG | Ozone grid | Data of ozone | HDF | P | |||||
AG | Tropospheric Aerosol grid | Data of aerosols | HDF | P | |||||
1BL | 1B HRVIR latitude plane | Data of the HRVIR co-location(latitude) | HDF | P | |||||
1BO | 1B HRVIR longitude plane | Data of the HRVIR co-location(longitude) | HDF | P | |||||
TG | Time grid | Each pixel is expressed with aprecision of one minute referring to the beginning of the firstsegment of the synthesis. | HDF | S | |||||
SZN | SZ NORM | This value is the normalized solarzenith angle used in the BDC correction. | HDF | D | |||||
TP | TAUP: Optical thickness | This value is the average of theoptical thickness of the selected measures of the BDCperiod. | HDF | D | |||||
Kxx | K0, K1, K2 for the the bands B0, B2,B3 and MIR | These values are the coefficients ofthe BDC correction function. | HDF | D | |||||
QL | Quick look | Quick look of one spectral band (seeLOG file which spectral band) | TIF | P/S/D |
P= VGT-Pproduct
S= VGT-S product
D= VGT-D product
TXT= text
HDF= Hierarchical Data Format
TIF= TIFF Format
Real NDVI =coefficient a * Digital Number + coefficient b
= a * DN +b
Coefficient a =0.004Coefficient b = -0.1
Real reflectance value VGT
=coefficient a * Digital Number + coefficient b
= a * DN +b
Coefficient a = 0.0005Coefficient b = 0.0