curtain queries

[bbell]

implement curtain rod type queries via rasql for line segments, linestrings, and polygons in 2D cross-sections.

the idea for now would be to have query options for:

select clip(curtain(c, range( arg ), polygon( arg )) from test_coll as c

select clip(curtain(c, range( arg ), line( arg )) from test_coll as c

select clip(curtain(c, range( arg ), linestring( arg )) from test_coll as c

[bbell]

polygon curtains have been introduced for 3D datasets in community, and we will continue to expand upon it and modify the syntax

currently, you can do a polygon clipping on a 3D dataset by specifying the 2D slice you want it in, but a curtain by default (for now) uses the last 2 dimensions for the polygonal crossection, and the range argument is the limits of integration for the curtain. i.e.:

select clip(curtain(c, range(0, 19), polygon(0 0, 9 9, 0 9)) from test_coll as c

future modifications will include specifying the range subset via c[0:19,*,*] in the mddexp argument to simplify the syntax, and to permit selection of the crossectional dimensions automatically through the subsetting, as well.

[Dimitar Misev]

so should be closed now? Otherwise update the description.

[bbell]

updated syntax to:

select clip(c[], curtain(…))

and as such, should be closed