WMS - WCPS fragment to compute difference between two slices in WMS style

[Bang Pham Huu]

From rasdaman user groupd with 6D coverage ​http://mapvue-test.s3-website-us-west-2.amazonaws.com/, the WMS style of this coverage iem_ar5_cruts31_temp_precip_wms works incorrectly for X and Y bounding box when WCPS fragment has the slicing coordinates.

For example:

# style 2

$c[period(1), scenario(0), season(0), model(0)].tas

# style 3

$c[period(1), scenario(0), season(0), model(0)].tas - $c[period(0), scenario(0), season(0), model(0)].tas

which can be reproduced by importing 2 tiff files to build a 3D coverage in the attachment and create a WMS style as below

$c[ansi("2020-12-30T23:54:58.500Z")] -  $c[ansi("2021-01-04T00:15:04.500Z")] + 30

http://localhost:8080/rasdaman/ows/?bbox=70586.06568358302,969097.8829550613,594874.0656835827,1493385.8829550543&crs=EPSG:3338&format=image/png&height=256&layers=test_wms&request=GetMap&service=WMS&srs=EPSG:3338&styles=subset_temperature_new1&transparent=true&version=1.3.0&width=256&time="2020-12-30T23:54:58.500Z"