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Home - General / All posts - EPSG:31370 revisited
yves61
435 post(s)
#30-Oct-23 10:11

Has any progress been made to cover this projection issue since my questioning 3 years ago ?

All vector and raster data from official Belgian sources come with EPSG : 31370. Unfortunately, Manifold does not handle this projection as this projection uses a latitude of origin (center latitude) of 90.0.

There is a manual hack by using a Center of Latitude of 50.79936 and a False Northing of 135372.956 as Dimitri pointed to in this thread https://georeference.org/forum/t153719.11#153727 and this thread https://georeference.org/forum/t153719.11#153733

But.... with each new M9 build version I am hoping for Manifold to override the internal EPSG:31370 settings automatically by using this hack : a Center of Latitude of 50.79936 and a False Northing of 135372.956

I am re-reading Dimitri's suggestion that ... Manifold should either adjust those projections as listed in Manifold to use the parameters that EPSG recommends for non-special case LCC, and not rely on people knowing to do that manually, or Manifold should in addition to the usual LCC projection implement the special case LCC routines that wouldautomatically swing into action anytime somebody quotes a Center latitude of 90 for LCC.

The former is a quick hack but the latter is the right thing to do.

Dimitri


7,400 post(s)
#30-Oct-23 15:34

If there already exists a fast and easy, single-click solution then providing another way of doing that isn't going to be a high priority item (see the Suggestionspage).

Going back to the first thread you posted, I remarked:

The problem fundamentally is that both EPSG 31370 as well as "Belgium National Geographic Institute" as writtenrequire a special case form of LCC, that Manifold does not support (QGIS doesn't either, but Arc does). Change the parameters as EPSG advises (as quoted in my earlier post), and then the usual form of LCC, which Manifold does support, works fine.

There is an existing solution, using the usual form of LCC, and that solution is something that EPSG itself advises. Implementing a special form of the LCC wouldn't even be a significant convenience, since you could save the EPSG recommended solution as a Favorite. You'd then have it ready to use with a single click. Why not just do that?

yves61
435 post(s)
#30-Oct-23 15:44

Dimitri,

Right, this is what I presently do, but I hope that Manifold would - on detecting a component with EPSG:31370 projection, which Manifold cannot project - automatically assign it the alternate projection with the modified Center of Latitude and False Northing.

I have sent in a repeat suggestion at sales@manifold.net

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