AAIGrid: CreateCopy does not preserve DataType

[Mike Taves]

Here is a minimal example, tested with GDAL 1.11.2 and 2.0.0

from osgeo import gdal
asc_drv = gdal.GetDriverByName('AAIGrid')
mem_drv = gdal.GetDriverByName('MEM')
nrow, ncol = 50, 20
ds = mem_drv.Create('', ncol, nrow, eType=gdal.GDT_Float32)
out = asc_drv.CreateCopy('out.asc', ds)
print(gdal.GetDataTypeName(out.GetRasterBand(1).DataType)) # Int32

The expected DataType is Float32, e.g. from mem_drv.CreateCopy('', ds). The data type should be copied from the provided template dataset, as is documented for CreateCopy.

[Mike Taves]

It should be noted that the expected behaviour of preserving Float32 is done when any raster value from the memory dataset appears like a float, such as 1.1, but not 1.0.

[Even Rouault]

Fixed with #6060