place: support rectangle, radius

[synrg]

Support specifying a place as a radius.

• in a query, within <#>km of <point-place> or a rectangle bounds <swlat>,<swlon> <nelat>,<nelon>
• or the same constructs used in [p]add place

[synrg]

We discussed on #inat-questions on the iNat Discord today another related use case, finding observations within a certain radius of a reference observation. It can be done manually as per:

1. Open your observation Details to copy the lat=# and lng=# values.
2. Select a radius=# (in km).
3. Add these to an existing search URL selected through the Observations search UI.

For example, https://www.inaturalist.org/observations?user_id=benarmstrong&lat=44.640001&lng=-63.683429&radius=0.1 for a search for 100m around a particular observation (the spotted sandpiper seen July 5, 2020).

[synrg]

We now have the circle and rectangle map tools on the web announced Oct. 2022 on the forums here: https://forum.inaturalist.org/t/new-rectangle-and-circle-drawing-tools-for-web-explore-page/36684

Since this is by far the most convenient way to get the coordinates, this feature should be able to take URLs containing the coordinates as input, as an alternative to specifying the coordinate pairs / point place & radius.

[synrg]

Keep it simple for now with just from accepting coordinates as follows.

• signatures for rectangle/radius coordinate parameter lists:
  • parse parameter names below with urllib.parse or accept one of the following positional signatures from comma-delimited or blank-delimited lists of values:
  • 2 decimal numbers is a point place of lat,lon
  • 3 decimal numbers is lat,lon,radius describing a circle
  • 4 decimal numbers is nelat,nelon,swlat,swlon describing a rectangle
• coordinate notation / units:
  • lat & lon in one of two notation systems:
  • decimal degrees (positive is N/W, negative is S/E) suffixed optionally by degree symbol and/or N/W
  • degrees, minutes, and seconds, e.g. 44°39'06.7"N 63°44'16.4"W
    • convert any curly-quotes or other equivalents to ascii before parsing as deg, min, seconds
    • convert to decimal before passing to iNat
    • any library to handle input like this?
  • in either case, ignore whitespace around non-blank delimiters/suffixes

Combining named places and radius not addressed in first version (i.e. the original within idea). Create a new issue for that.