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I'm creating charts for routes that fall within two UTM zones; 30S and 31S. The offshore routes are in the Alboran / Balearic Sea - connecting Spain to Algeria.

What projection should I use?

marked as duplicate by AndreJ, PolyGeo Jan 12 '16 at 8:05

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  • What is the purpose of the map? Is it for nautical navigation? – ed.hank Jan 11 '16 at 16:14
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    How far do the routes span the two zones. i.e is most of the route in zone 30 and a few miles in 31? What geodesy was the data collected in? Whats the deliverable charts or web map? If this is for a customer, you need to have this discussion with your client. – risail Jan 11 '16 at 16:46
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    Make sure you don't confuse "S" = latitude band versus "S" = South zone. Many GIS software uses N / S = North / South not latitude bands. For charts? Mercator is often used because loxodromes/rhumb lines are straight. – mkennedy Jan 11 '16 at 17:56
  • Hi. Thank you for your comments I meant to write N - I was just looking in Google Earth and accidentally wrote the grid name! It's definitely in the Northern hemisphere. We'll be doing a bathy / geo survey in the Alboran / Balearic Sea prior to laying subsea cable. The majority of the survey will take place in 31N. Width wise, approximately 261km will be within zone 31, while the remaining 76km will be in zone 30. If they want it projected in UTM, it definitely makes sense to use zone 30. Like you said, will have to discuss with client. – J. Rushton Jan 12 '16 at 17:04