Getting pixel values from MODIS level 3 product using ArcMap

Question

I wanted to find and map pixels with a certain chl value from the downloaded MODIS Chl data from NASA ocean color web. When using 'identify' tool (ArcMap), I can view the particular pixel value but I want the entire pixel values to be listed as an attribute table. I read somewhere that when the values are in float, one could not create an attribute table so I used raster calculator to multiply the raster layer with 10^7 since the lowest value was 0.0575846. But now the then highest value 79 becomes a float like 7.9*10^6. I tried in both GeoTIFF and netCDF format of data but both perform the same way.

Is there a way to get the attribute table with data from every single pixel of this image using ArcMap?

• PolyGeo: If you also wish to ask about doing this using ENVI then please do that in a separate question.

Answer 1

Float rasters do not have attribute tables, only integer rasters can have an attribute table. You are correct that multiplying the value by multiples of 10 shifts the decimal point and enables you to represent the values as integers in an attribute table.

Nothing wrong with that approach you just need to remember to divide by the number you multiplied to get back to the original value.

An advantage of storing the values as integer is that it takes up less memory so integer rasters are typically much smaller in size.

An alternative approach is to convert the raster to a point dataset. The advantages of that is that you have an attribute table with the value and also the location as a point. The disadvantage is that a large raster creates a very large point dataset so I would recommend you write the output to a file geodatabase, do not use a shapefile format.