Conversions between GeoTools GridCoverage2D and GeoTrellis Raster types - #1502

According to the documentation[1], DataBuffer.TYPE_BYTE corresponds to
"unsigned byte" not "byte".

1. https://docs.oracle.com/javase/7/docs/api/java/awt/image/DataBuffer.html

Since all bands of Geotrellis MultibandTiles must all have the same
cellType and NODATA value, that particular type is not a good candidate
for representing the data in a GeoTools GridCoverage2D.  The best analog
of a GeoTools GridCoverage2D is an Array of Geotrellis Rasters.

Also, the converter now emits *ConstantNoDataCellType when it can.

The Raster[Tile] to GridCoverage2D transformation provides best-guess
ColorModels to the created GridCoverage2D objects.  The
Raster[MultibandTile] to GridCoverage2D transformation does not attempt
to provide ColorModel information.  NODATA metadata is now correct in
both the Tile case and MultibandTile case.

Since all bands of Geotrellis MultibandTiles must all have the same
cellType and NODATA value, that particular type is not a good candidate
for representing the data in a GeoTools GridCoverage2D.  The best analog
of a GeoTools GridCoverage2D is an Array of Geotrellis Rasters.

Also, the converter now emits *ConstantNoDataCellType when it can.

The Raster[Tile] to GridCoverage2D transformation provides best-guess
ColorModels to the created GridCoverage2D objects.  The
Raster[MultibandTile] to GridCoverage2D transformation does not attempt
to provide ColorModel information.  NODATA metadata is now correct in
both the Tile case and MultibandTile case.

…versions