[PROJ] Proj-Lib 7.2 Custom EPSG Codes

Michael Morelli m.morelli_osrc at outlook.com
Wed Mar 31 08:43:03 PDT 2021



Hi folks,

hope you are doing well!

we are about prototyping with proj-lib (Version 7.2).

1. Insert and Use a custom PCS-Code

We would like to add our own custom PCS-Codes (and GCS-Codes) with a custom authority-name.
Is it correct that the only way to add custom Codes is to insert it directly via sqllite and not via the C-API?
So for a new PCS we could add a row into the table projected_crs with auth_name = 'CUSTOM_AUTH', code = '1', name = 'a custom pcs' and text_defintion = '[WKT-Definition]'.
We could then successfully use this custom-epsg to use it as src- or tgt-Projection (CUSTOM_AUTH:1) in the function proj_create_crs_to_crs() for transforming with function proj_trans().
This worked so far.

Also using the following function worked:
PROJ_STRING_LIST projStringList = proj_get_codes_from_database (C, AnsiString ("CUSTOM_AUTH").c_str(), PJ_TYPE::PJ_TYPE_CRS, 1);

But when using the following new function (without a filter):

PROJ_CRS_INFO** returnedList = proj_get_crs_info_list_from_database (C, AnsiString ("any").c_str(), 0, &count);

Then the Code CUSTOM_AUTH:1 was not in the returned list. Are we missing something or is this a bug?
(The custom code exists in the sqllite view: crs_view and table: projected_crs..)

2. Replace GCS of PCS
In some cases the end-user should be able to select a PCS and then replace the GCS of this PCS with another different GCS (would result in a new custom PCS).
In the C-API we could not find any setter-functions to set a GCS to an existing PCS PJ*-Object.
Is there an elegant way to do this?

Thx in advance for your interest.

Kind regards,
Mike


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20210331/ce42eae3/attachment.html>


More information about the PROJ mailing list