Location Selector

We want a widget which can be embedded within a form to be able to select the appropriate location to associate with a record using either hierarchical dropdowns or a precise location.

Status

We have a widget in views/gis/location_autocomplete.js

• this is added manually to many view templates (often this is the only customisation for that view)

This supports:

• Hierarchical Level selector to choose the correct level or select the correct Parent
  • The country selector remains hidden if there is only 1 country being used (as per deployment_settings).
  • The number of levels available depends on the deployment_settings.
  • Initially just a single dropdown is displayed.
  • When this dropdown is selected then the next dropdown is displayed, along with appropriate values
    • We download the values via AJAX in order to not have to download all Locations
• The user has the option of adding a more specific Name & a Street Address
  • This is not mandatory as some records need to link directly to the L0-L4 levels.
• Geocoder lookup of a Street Address
• Map-based lookup of Lat/Lon
• Manual entry of of Lat/Lon (either from a GPS or looked up in an online resource like Wikipedia)
  • A Conversion tool is available to convert from Deg/Min/Sec to Decimal Degrees

ToDo

• Redesign the Look/Feel to make it more usable
  • Display all the Lx layer dropdowns from the start?
  • Hide the 'Add New Location' options behind a button (CSS Hide)
  • Hide the Lat/Lon entry forms behind an 'Advanced' button (CSS Hide)
  • Don't load the Map within the page but do this as a separate server-side call
• Make it work with components (see below)
• Move the implementation to a server-side widget so that it applies automatically to all instances of the field (can then remove from custom view templates)
• Add an HTML5 GeoLocation option ('Current Location')
  • we should use a 'nearby' algorithm (like gis.get_features_in_radius()) to re-use existing locations rather than adding a new one each time.
  • e.g. pr/person/presence could be recorded automatically upon login
• Set the map entry default lat/lon/zoom based on the selected Level in the Hierarchy (assumes we have at least Centroid information available, ideally use Polygons where we have them)
• Display the geocoder results on a map for visual confirmation that the correct result has been returned
• If we have admin boundaries available then the Lat/Lon provided can be validated against the selected Lat/Lon
• If we have admin boundaries available then the correct hierarchy can be filled-in automatically if just the Lat/Lon are provided

Known Issues

There are various bugs in the current implementation, some of which are listed below.

Duplication of location records

This happens when you for example create a new hospital record without creating a new location, but just selecting one (just select a country, for example). When you submit, then a new location record is created with the same name as the selected one - this seems wrong. You can make it visible by uncommenting the show_status line. The reason for this behaviour is that S3.gis.uuid is empty in case there is no old_location, which triggers the creation of a new record. Thus, this does not happen in update, and not either when you create a new location (which creates a new location anyway :D).

Use in Component Forms

To be able to apply the location selector to components (e.g. person/presence, where it would be *very* useful), we need to go away from the 'request.controller+"_"+request_function' construction and instead use jr.

Perhaps this way:

 {{try:}}
   var location_id = '{{=jr.prefix+"_"+jr.target()[1]+ "_location_id"}}';
 {{except:}}
   var location_id = '{{=request.controller+"_"+request.function+ "_location_id"}}';
 {{pass}}

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PakistanDevelopers#LocationsSelector

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