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If the interest is in re-creating a presentation seen in a commercially published map, are you sure that commercially published map uses UTM (Universal Transverse Mercator) and not TM (Transverse Mercator)? The reason I ask is that UTM is a discontinuous projection system. It is a series of TM projections, not just one projection. Conceptually, those projections are just as genuinely different from each other as would be, say Mercator and Orthographic. If you have a drawing in one UTM zone and a drawing in a different UTM zone those two drawings are in different projections. Each UTM zone projection is intended to show objects only within the zone. If you want to show a region that is on the border between two different UTM zones the presentation would be to show two rectangular windows overlapping each other, with each window having its own border coordinates. It is just as if you had two paper maps, one drawn in Mercator and one drawn in Orthographic which had some region on their border in common and you wanted to "combine" them by laying them out on a desk: what you'd see if you photographed that table from above would be some arrangement, or layout, of those paper maps that you'd try to move about so that the region of overlap despite the different projections used would seem reasonably continuous, more or less satisfactorily, for your purpose To show objects on or near the border of two different UTM zones, if you prefer TM style projections, the solution would be if there were a UTM zone defined that is centered upon the border region. But since what makes UTM "universal" is the predefinition of discrete zones that is not available to you in UTM. So instead what you do is use TM, upon which UTM is based, to create a TM projection of the data that is centered upon the border zone. You can then create a single drawing that shows objects from two different UTM projections within a single TM projection that is centered on your view and thus minimizes distortion. Note that the above is not a consequence of anything having to do with Manifold, per se. It is a consequence of how projections work and how the family of different projections collectively called "UTM" have been designed to operate.
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