Downscaling raster maps: Difference between revisions
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''' | '''Question''' | ||
''' | What is be the recommended way to downsample a raster map? | ||
r.resamp.interp, r.resamp.stats, r.resamp.rst, r.mfilter.fp, or any | |||
'''Answer''' | |||
The "best" way is subjective, but the main options are | |||
{{cmd|r.resamp.interp}}, {{cmd|r.resamp.stats}}, {{cmd|r.resamp.rst}}, {{cmd|r.mfilter.fp}}, or any | |||
combination of those. | combination of those. | ||
Another option is to use i.fft followed by i.ifft with a | Another option is to use {{cmd|i.fft}} followed by {{cmd|i.ifft}} with a MASK applied. | ||
However, that requires that your raster contains no null cells (so you | However, that requires that your raster contains no null cells | ||
may need to use e.g. r.fillnulls first), and it also requires that you | (so you may need to use e.g. {{cmd|r.fillnulls}} first), and it also requires that you | ||
can fit the entire raster in memory (so it isn't suitable for very | can fit the entire raster in memory (so it isn't suitable for very high resolution data). | ||
high resolution data). | |||
[[Category: FAQ]] | [[Category: FAQ]] | ||
Revision as of 15:54, 5 February 2013
Question
What is be the recommended way to downsample a raster map?
Answer
The "best" way is subjective, but the main options are r.resamp.interp, r.resamp.stats, r.resamp.rst, r.mfilter.fp, or any combination of those.
Another option is to use i.fft followed by i.ifft with a MASK applied. However, that requires that your raster contains no null cells (so you may need to use e.g. r.fillnulls first), and it also requires that you can fit the entire raster in memory (so it isn't suitable for very high resolution data).