By carefully deriving the NDVI values from Landsat Band 3 and Band 4 after doing atmospheric correction by applying DOS1 method in semi-automatic classification Plugin QGIS, I was to calculate the Green Vegetation Fraction by using equation as I mentioned in my previous post post1 (also mentioned below, here), in which @WhiteboxDev. nicely explained the problem that might would occur. I had put the wrong NDVImin and NDVImax range and this was happened due to not seeing in the metadata rather by seeing visually in QGIS. In my second post post2, @SaultDon. pointed me the that mistake that actually, I was doing.
GVF = (NDVI - NDVImin) / (NDVImax - NDVImin)
After using the minimum and maximum values shown in the metadata, I recalculated the Green Vegetation Fraction by using the same equation that i have mentioned above, now the ranges starts form 0.12-0.90 in metadata, not visually.
My question is that what is the difference between the values ranges that have shown in visually and metadata. And also I want to make the color map that shows the ranges between 0-0.20, 0.20-0.40, 0.40-0.60, 0.60-0.80, 0.80-1.0 in a index form. I have done this in QGIS by clicking the layer properties in style menu and by selecting the singleband psedocolor in renter type and to generate new colour map I have selected continuous mode and 0 as minimum and 1.0 as maximum values. I have changed these values manually, did not take those values that already shown in it (the same values that visually displayed and these are not the actual values). Am I doing right or how can I do it otherwise to make the such figures that Hu and Jia (2010) made in figure 4 in attached paper, I have also attached band 3 and band 4 data of landsat paper, band 3 and band 4. Briefly explain about how to make the colour maps in style menu of layer property dialogue box by using mode "continuous/equal interval" with minimum and maximum values. If One would manually change these values then what happened with the colour map that will display.