Even, Ray, thanks for the answers
22.06.2015 23:28, Ray Gardener пишет:
The functions are to allow mapping between logical and physical pixel
values. This is very common in e.g. elevation DEMs.
Applying them is done by the calling code. At least, I haven't seen
any routines in GDAL that
would apply them for you.
Ray
On 6/22/2015 7:50 AM, Alexander Bobkov wrote:
Hi,
What is the intended usage of methods
SetScale/GetScale/SetOffset/GetOffset of the GDALRasterBand class?
Documentation says that
This value (in combination with the GetOffset()
<http://www.gdal.org/classGDALRasterBand.html#ab62e0761dde3e3b76f83155920275e4f>
value) is used to transform raw pixel values into the units returned
by GetUnits(). For example this might be used to store elevations in
GUInt16 bands with a precision of 0.1, and starting from -100.
Units value = (raw value * scale) + offset
Who is responsible for applying the formula: client code before/after
RasterIO operation, or driver code inside IReadBlock/IWriteBlock methods?
Best regards,
Alexander Bobkov
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