Hello,
I want to get NDVI data from EO browser, using Landsat 7 ETM+ L2 for the following years: 2007-2022. I have some geojson files with all the polygons that i want to get data for. However, Landsat 7 has some scan lines with no values. Should i be getting NDVI values using these polygons? Will it be reliable? Are these values taken into account when I get the statistical info?
Hi Paraskevi,
Thanks for the question; yes, Landsat 7 has been affected by the scan lines for a significant period of time. You can still obtain statistical information from this data, but depending on your AOI, you won’t be getting the full picture as many pixels will not have a value. Therefore, it is difficult to say how reliable this data would be. However, using the dataMask band, when you run your request, you will only be returning the statistics for valid pixels.
Alternatively, you could experiment using Data Fusion in your investigations. For example, you could use Landsat 8 L2 data to “fill” in the gaps where there is no data. However, you would need to consider the validity of this approach as the different datasets will probably not be obtained on the same dates.
Thanks for the reply. Can I also ask; if I do use the specific geojsn files and get the statistical data for the specific polygons that I’ll import on EO browser, are the values NAN taken into account? Are they used as 0 values so the mean values that I’ll be getting in the end won’t be as reliable?
As I said, as you need to use the dataMask band in any statistical request, any NAN pixels are excluded from the calculation.
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