fwa_indexpoint - add option to only return streams associated with the fundamental watershed in which the point occurs

[smnorris]

This is unlikely to guarantee the function will only return streams that the point will flow to, but it should do so in the vast majority of cases.

[smnorris]

While a 'within_same_watershed' option for the function would be great, it is not so simple in many locations. Consider adjacent to double line rivers: https://features.hillcrestgeo.ca/fwa/collections/whse_basemapping.fwa_watersheds_poly/items.html?watershed_feature_id=8492825

If asking for only features within the watershed in which the point is found, the Cowichan would not be included in the results, just the side channel and a disconnected pond.

It might be better to encourage the user to cast a fairly wide net, return a few indicators about how the stream and point relate and let the user choose the best match (mostly because input points tend to be inaccurate anyway, user should generally be checking against several matches to see if they are getting the best stream, usually by name).

Otherwise, maybe options like this:

fwa_indexpoint(x,y,srid,tolerance,num_features, match_type, include_disconnected, include_null_localcodes)

Where
match_type: nearest=return closest stream, flow=return only streams within same watershed or downstream
include_disconnected: true = include 999 streams
include_null_localcodes: true = include streams with null localcode

So, for general networking purposes, presuming input point is of good quality:

fwa_indexpoint(x, y, srid, 100, 1, flow, false, false) would give the best single result.

[smnorris]

Another issue with the function is that bc_ind is based only on intersection with watershed group polys. A better check is needed. A marine/terrestrial flag would be useful too.