Comments on: Maps and Coordinates

Question: Maps and Coordinates

dodgygeezer — Fri, 26 Nov 2004 06:49:59 -0800

Maps and coordinates. I'm testing out the feasibility of using maps on my website. The website providing the maps asks for particular types of coordinates yet I can't seem to find a way of working out what my coordinates should be. This could be complicated to explain so... [more inside]

So I want to use Map24.com to map my users coordinates and to show their nearest neighbours

In the docs they give this example of usable coordinates:
Location in World coordinates (stated in minutes).
Example Mapsolute HQ in Eschborn:
wx=514.227597291174&wy= 3007.8407347798347

So my plan is that if my users can get their coordinates from somewhere then they can just enter X and Y into their profile and we're laughing.

The problem is I can't work out where they can get these coordinates from. For example if I find an address on Multimap it gives me the following coordinates:
X: 530400m
Y: 184800m
Lat: 51:32:49N (51.5471)
Lon: 0:07:13W (-0.1202)

Which is great, except it seems to bear no relation to what Map24 wants and any version of those numbers that I put in ends up going straight into the sea. Splash.

So my questions are:
Can I easily convert those coordinates?
Can I find a better source for providing my users with coordinates that'll be Map24 compatible?
Is there a better all round solution somewhere else?

By: Leon

Leon — Fri, 26 Nov 2004 07:42:48 -0800

From the user's point of view, the easiest way to locate yourself in space is by post/zip code. I'd look for a way to convert from postcode to [co-ord system of choice]. It's likely you'll have to pay for this data.

I haven't used the service you're talking about, but I worked with mappoint.net a few years ago which had lots of handy functions for converting between co-ordinate systems, but it's not cheap.

Without seeing the specs, my guess is that in the first system values are expressed as [minutes].[decimal parts of a minute], and in the second as [degrees] [minutes] [seconds]. Google might help with converting to/from various different types of lat/long.

By: MzB

MzB — Fri, 26 Nov 2004 08:08:55 -0800

Use this to get the location in lat/lon: Heavens Above

Regarding map24, world coords might be just the position of the viewport and its position is based on some sort of internal computations. If you store these locations it is better to use a well defined system such as Lat/Lon so that you do not depend on a particular application.

By: nicwolff

nicwolff — Fri, 26 Nov 2004 08:54:18 -0800

The coördinates in minutes are just the longitude and latitude in decimal degrees multiplied by 60. Eschborn, e.g., is at 8.55W 50.13N.

By: BradNelson

BradNelson — Fri, 26 Nov 2004 09:34:32 -0800

This is possible to do by IP as well. A friend of mine did it, but I'm not really sure how. Problem is, it's not always accurate.

By: dodgygeezer

dodgygeezer — Fri, 26 Nov 2004 10:30:47 -0800

OK, this looks very cool then.

All the users need to do is enter their latitude and longtitude using either multimap or Heaven's Above (handy link - thanks!) then when I want to link to the map page I can just times those numbers by 60 and call the link.

Leon: There is an option to use addresses and postcodes instead (and it works pretty well) but I'd rather not use it as there may be privacy concerns amongst the users.

Thanks everyone!

By: jimmythefish

jimmythefish — Sat, 27 Nov 2004 10:03:51 -0800

As per the X and Y coordinates, it looks like they're in UTM (Universal Transverse Mercator).