Within a QGIS-course I would like to tell a bit about the proj.4 parameters. However, I'm not sure about the "+no_defs" parameter. The proj.4 website (http://proj4.org/parameters.html#parameter-list) says:

+no_defs Don't use the /usr/share/proj/proj_def.dat defaults file

Can anyone explain me what this means? (What would it mean to use the /usr/share/proj/proj_def.dat defaults file?)

2 Answers 2


Finally I found this thread, which answers the question for my needs:

The "no_defs" item ensures that no defaults are read from the defaults files. Sometimes they cause suprising problems.



In modern versions of the library, +no_defs means nothing.

Since v6.0.0, the default settings file has been removed. That means that the +no_defs option is obsolete if you're using modern versions of the libraries.

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