AVHRR NDVI3g. 30+ Years of LAI3g and FPAR3g Data Sets We are providing you free access to a 30+ year long global data sets of vegetation leaf area index (LAI3g) and fraction vegetation absorbed photosynthetically active radiation (FPAR3g). These data sets were derived from the third generation GIMMS NDVI3g data set (hence the suffix "3g"). The data sets are at 1/12 degree resolution, 15-day composites (2 per month) and span the period July 1981 to December 2011. A set of neural networks were first trained on best-quality and significantly post-processed MODIS LAI and FPAR products and AVHRR GIMMS NDVI3g data for the overlapping period (2000 to 2009). The trained neural networks were then used to produce the LAI3g and FPAR3g data sets. Please note the following: (1) If you wish to submit an article to the special dedicated to NDVI3g/LAI3g/FPAR3g of the open source journal "Remote Sensing" you are welcome.
. (2) The article describing the LAI3g/FPAR3g by Zhu et al. can downloaded from the Special Issue. Spectral Hourglass Wizard (Using ENVI) | Exelis VIS Docs Center. Use the Spectral Hourglass Wizard to guide you step-by-step through the ENVI hourglass processing flow to find and map image spectral endmembers from hyperspectral or multispectral data. The Wizard displays detailed instructions and useful information for each function. From the Toolbox, select Spectral > Spectral Unmixing > Spectral Hourglass Wizard to start the workflow.
The following chart shows the processing flow: The hourglass processing flow uses the spectrally over-determined nature of hyperspectral data to find the most spectrally pure, or spectrally unique, pixels (called endmembers) within the dataset and to map their locations and sub-pixel abundances. This processing flow begins with reflectance or radiance input data. The name of the corresponding ENVI function appears at the top of the panel during each step. After starting the Spectral Hourglass Wizard, refer to the following sections for help:
Reverb | ECHO. SRB Data and Information. GEOSTATIONARY SATELLITE SERVER. Grace. Modis. TRMM.