Feature: IVEA projection#3
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Leaving open for reference, but will require reworking to be compatible with new approach that uses conway meta to cut up the polyhedron and a definition for the parents net |
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| polyhedral::load_triangles(Q, decakis_dodecahedron::SPH_TRI, nets::dsea::icosahedron::FACE_TRI); | ||
| polyhedral::set_orient_from_angles(Q, ISEA_STD_LAT_DEG, ISEA_STD_LON_DEG, IVEA_AZ_DEG); | ||
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@felixpalmer Curious about this (IVEA_AZ_DEG) here...
Is that the azimuth from DSEA's perspective?
If so, that might be problematic if trying to override +proj=ivea with +azi from ISEA/IVEA's perspective?
Is that positioning the vertices of the icosahedron at ISEA_STD_LAT_DEG, ISEA_STD_LON_DEG, or the vertices of the dodecahedron?
Also wondering if you updated this PR already or it still needs refactoring (it shows no conflict)?
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No this PR is out of date, no point keeping it as the other branch has diverged too much
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@felixpalmer Thanks for clarifying that. Still really hoping for a follow-up PR for +proj=ivea support though :)
Are you leaving that to me or were you planning to update this one yourself? :)
I'm also wondering if we could have a +net=5x6 that could work across all the icosahedral ones like dsea and isea (and eventually tisea), before we have the full blown affine transformation available... When selecting that net, dsea and ivea would be exactly the same (the only difference for ivea is that it defaults to an icosahedron net).
I guess currently the nets are specified as the number of faces for the selected solid, rather than the component kis or meta triangles though, right? I was thinking depending on the count of faces in the net, it could auto-select the right mode (for the eventual +proj=polyhedral, but also for the these internal nets like +net=5x6, +net=dymaxion, etc.)
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Overview
This PR is stacked on top of the root PR: OSGeo#4758 - please see there before reviewing
Projecting with
DSEAonto a icosahedral net yields a better result (less cusps) that usingISEA. This approach has been referred to asIVEAin some places, for example https://dggal.org/The purpose of this PR is to show how an alias can be added for an existing projection to make it easier for end users - some of whom may find it confusing that a dodecahedral projection can be unfolded onto an icosahedral net.
Change list
Example renders
IVEANote cusps compared to IVEA