-----Original Message----- From: openguides-dev-bounces@openguides.org [mailto:openguides-dev-bounces@openguides.org]On Behalf Of Jo Walsh Sent: 28 June 2004 00:42 To: OpenGuides software developers Subject: [OpenGuides-Dev] locator plugins

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an additional piece of data by way of the ellipsoid. This needs to be prompted for in the setup, and held in the config file.

i kind of assume it will always be wgs84 - 23 for Geo::Coordinates::UTM - or nad83 which is centimetres of difference. this is what gps, the big mapping sites, etc use

• this could be a default config option without a prompt?

I thought that you needed different ellipsoids for different parts of the globe. wgs84 or nad83 may work well for California, but I doubt if they would for Europe.

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In terms of metadata, the module needs (and relies on)

latitude and longitude.

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The pythagorean distance finder needs zone, easting and

northing. The plugin

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will provide these via the location method. The distance

finder needs zone,

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easting and northing to be stored in the database.

i never needed to use the zone, but things will blow up if a guide spans more than one and gets different spatial references? as 'easting' and 'northing' rather than os_x / os_y?

The zone is just there as a memorandum field. The distance finder only detects locations in the same zone as the place you are searching from.

Also, the distance method checks the zone. I guess it could return undef, and allow calling code to use a different distance algorithm - such as one which works off lat/long.

I only think this is an issue when we get a guide that spans multiple zones.

then i think the 2 plugins should be totally compatible, and i just change mine to use base CGI::Wiki::Plugin::Locator::UTM, and add the geocoding method. nice one ivor.

Good! That shows my initial idea was sound :).

a further thought! Schuyler objects that distances in metres and kilometres meant little to people not used to seeing them / converting between them and yards/miles, e.g. pesky merkins. i could do metre/mile conversion and change the distances - or keep it like it is - but it's definitely a question.

Sounds like a case for using Data::Dimensions.

Ivor.