轉(zhuǎn)載:http://liangshzh0816.blog.163.com/blog/static/3477676200972383052319/?suggestedreading&wumii
VEGETATION傳感器于1998 年3 月由SPOT-4 搭載升空,,從1998年4 月開始接收用于全地植被覆蓋觀測的SP0T VGT數(shù)據(jù)。VEGETATION 數(shù)據(jù)主要由瑞典的Kiruna 地面站負(fù)責(zé)接收,由位于法國Toulouse的圖像質(zhì)量監(jiān)控中中負(fù)責(zé)圖像質(zhì)量并提供相關(guān)參數(shù)(如定標(biāo)地?cái)?shù)),最終由位于比利時(shí)的VITO研究所的圖像處理與存檔中中負(fù)責(zé)全地VEGETATION 數(shù)據(jù)存檔與用戶定單。
太陽同步圓形近極地軌道軌道高度:832公里
軌道傾角:98.721度
軌道周期:101.469分/圈
重復(fù)周期:369圈/26天
降交點(diǎn)時(shí)間:上午10:30分
掃描帶寬度: 60 公里
兩側(cè)側(cè)視:+/-27度 掃描帶寬:950公里
spot vgt的幾個(gè)波段及用途
mainly to perform atmospheric corrections 主要用于大氣校正
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數(shù)據(jù)主要有
vgt d10產(chǎn)品指的是bdc或二向反射合成,這種合成方法是基于二向反射率函數(shù),像元的灰度值為地面反而反射率,海洋地區(qū)的反射率設(shè)為0,和s10一樣有三種合成產(chǎn)品1km 4km和8km
那么mvc和bdc產(chǎn)品有什么區(qū)別呢,主要表現(xiàn)在status map 和新增以及去除一些內(nèi)容
不同產(chǎn)品的數(shù)據(jù)內(nèi)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
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