Null values not shown in coverage description

[Dimitar Misev]

This is more of a questions: in petascopedb we have null values associated with a coverage, but they are not included in the DescribeCoverage for example. Not sure if they can be included?

[Peter Baumann]

yes, they can (and should, if present) go into the rangeType where it is foreseen by way of schema.

[Piero Campalani]

This ticket needs to be addressed by means of a change of dbschema in the SWE quantities, as NiL values are not supported yet (see #582).

I suggest to patch this ticket along with #573.

[Piero Campalani]

Petascope and petascopedb updated in changeset:352f985.
Now 1+ NIL values (value, and associated URI-zed reason) are configurable in the database in the new ps_nil_value table, whose PK(s) are used by ps_quantity.

petascopedb=# \d ps_quantity
                                 Table "public.ps_quantity"
          Column        |   Type    |                        Modifiers                         
------------------------+-----------+----------------------------------------------------------
    id                  | integer   | not null default nextval('ps_quantity_id_seq'::regclass)
    uom_id              | integer   | not null
    label               | text      | default ''::text
    description         | text      | default ''::text
    definition_uri      | text      | 
    significant_figures | integer   | 
+++ nil_ids             | integer[] | 

petascopedb=# \d ps_nil_value
                         Table "public.ps_nil_value"
 Column |  Type   |                         Modifiers                         
--------+---------+-----------------------------------------------------------
 id     | integer | not null default nextval('ps_nil_value_id_seq'::regclass)
 value  | text    | not null
 reason | text    | not null
Indexes:
    "ps_nil_value_pkey" PRIMARY KEY, btree (id)
    "ps_nil_value_value_reason_key" UNIQUE CONSTRAINT, btree (value, reason)

Graphical schema (SchemaSpy) has been synced too.

Next step is to the creation of a script to generate custom SWE quantities for coverages.
While ​this describes how to do it manually on the database, it is surely safer not to let user do that manually (see #667)