A side project that I’m currently working on, involving maps, had a bit of data that I was unfamiliar with. I’ll start by saying that I’m very familiar with Latitude/Longitude – it’s something that everyone learns in school. However, the data that I was provided with was of an entirely different sort and labeled as ‘Easting’ and ‘Northing’. A couple Google searches later brought me to a an article explaining the concept of something called Universal Transverse Mercator (UTM). The article is very math heavy, but the premise is: The earth is broken down into tiny ‘zones’ around the ecuator and extending northing and south. Within these zones a measurement, in metres, is taken both to the north and to the east of the ecuator. So your final figure is something like Zone: 17, Easting: 300,000, Northing: 4,000,000 (I just made those numbers up). The reasoning for this is that if your measurements are within a tinier ‘slice’ of the world, your results immediately become more accurate (especially considering the curvature of the earth). Here’s a figure showing all the different zones, taken from this page on different coordinate systems:
Now, using that chart above I determined the zone in which I needed to run all my coordinates through – but the problem is: How to convert them into Lat/Long – which every piece of mapping software understands. There are a number of Java Applets which will do this task, but I wanted something that I could automate. This is where Perl, as always, comes to the rescue – there is a module for it! The module is very lightweight, it simply implements the algorithms specified in the article, mentioned before. Useing that module I was able to quickly run through my data and get perfect numbers out – concluding my UTM adventure. As always, more information can be found on Wikipedia.
The Map Room (July 19, 2005 at 9:52 pm)
Another Look at UTM
John Resig writes, “It seems to have been a while since The Map Room talked about Universe Transverse Mercator. I’ve written up my experences learning this alternative coordinate system along with a brief overview of how the system works. For…
Bill Chase (July 20, 2005 at 10:31 pm)
UTM grows on you with use. USGS topos are all printed with the grid and with practice it’s easy and more precise to “read right up”. Easting then northing.
Mohammad Khoshkhoo (December 13, 2005 at 2:55 am)
Dear John,
Please excus me that my comment is not releavant to your project. I have another problem that I just thaught you might help me. I have the UTM (east and north coordinates) of a point and want to find its map, gelogical or topographical, on the internet. Could you please introduce a website which has such this facility?
lookiing forward to hearing from you.
Sincerely Yours
Mohammad Khoshkhoo
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Chris Marijani (August 31, 2007 at 12:13 pm)
HAllow mr it seems your are right with idear but your chart figures no are not seen. i dont know if its how you print them.