I am new to GIS and working with gridded data so please excuse me if my question is simple or if I miss an obvious point.
I want to work with 30 Arc Seconds Nightlight Data (my data comes from NOAA: http://ngdc.noaa.gov/eog/dmsp/downloadV4composites.html). To my understanding with 30 Arc Second Grid Data, one would end up with a 43200x21600 resolution. As the provided data only covers from -65 to 75 degrees latitude (and full longitude), the resolution should be 43200x16800.
The provided data from NOAA however has a revolution of 43201x16801. My first thought was that maybe the last observations of the first row (the 43201th observation) equals the first one, but it does not really make sense to me why NOAA would include an "extra" and unnecessary observation. Why is there an "extra" pixel in the data?
My problem in the end is that I want to change the resolution later to a 1/12° (4320x2160) Grid. With a 30 Arc Second Grid, exactly 100 pixel (of which I take the average value) would fall into one pixel of my 1/12° Grid. But due to the "extra" pixel per row I am not sure how to do this. Could anyone tell me how to handle the extra pixel?
أكثر...
I want to work with 30 Arc Seconds Nightlight Data (my data comes from NOAA: http://ngdc.noaa.gov/eog/dmsp/downloadV4composites.html). To my understanding with 30 Arc Second Grid Data, one would end up with a 43200x21600 resolution. As the provided data only covers from -65 to 75 degrees latitude (and full longitude), the resolution should be 43200x16800.
The provided data from NOAA however has a revolution of 43201x16801. My first thought was that maybe the last observations of the first row (the 43201th observation) equals the first one, but it does not really make sense to me why NOAA would include an "extra" and unnecessary observation. Why is there an "extra" pixel in the data?
My problem in the end is that I want to change the resolution later to a 1/12° (4320x2160) Grid. With a 30 Arc Second Grid, exactly 100 pixel (of which I take the average value) would fall into one pixel of my 1/12° Grid. But due to the "extra" pixel per row I am not sure how to do this. Could anyone tell me how to handle the extra pixel?
أكثر...