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As mentioned by Aaron, if you want to analyse a time series of NDVI data, you need to make sure that it is computed in a consistent way (based on the reflectance values and not on the digit numbers). You can find more information here If you do so, NDVI will be between -1 and +1, and the larger the value the more "green leaves" you are likely to observe (I ...


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I should first mention that if your ASTER data are not calibrated to reflectance, you are not actually calculating NDVI correctly. Make sure you have the appropriate calibrations in place and are indeed using relectance values rather than DN, radiance or pixel brightness values. Very often products are already served-up to reflectance. The actual values ...


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Try converting your raster data set to points,use tool (get values to point) which will give you value of NDVI of every pixel to points. Then again you can convert to raster. OR Try 'calculate Statistics' in Raster tools.


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Pending there are no errors in your data or calculations, values for NDVI will always fall between -1 and 1. NDVI values are calculated from reflectance, which is the fraction of radiation that is reflected by a given surface. It sounds like your NDVI raster might be in integer format, which means you'll have rounding errors (e.g. raster displays '1' instead ...


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you can use gdal to do this if your input data is georeferenced, with gdalwarp you will need to specify the output size (-tr 1000 1000), the resampling method (-r bilinear) and I guess the projection of MODIS as output ( -t_srs "+proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs" ) so it should look like this in command line ...


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Never mind. I got it. When there is a detect a problem, it display the icon next to the layer name and you just right click on the layer name and you see a green check that says "Correct the Alert Problem". Thanks.


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Your problem is likely due to how your model handles bit-depth. EVI, like NDVI, ranges from -1 to 1 and has a practical range of 0 - 1. Therefore, if you try and perform the EVI (or NDVI) calculation and save it as an integer type raster (e.g. signed 8 bit), the output will appear to be black, or all one value. Rather, you need to save the output as a ...



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