Re: Datum Grids, Which Ones?
Kristian Evers <[email protected]>
| Newsgroups | gmane.comp.gis.proj-4.devel |
|---|---|
| Message-ID | <[email protected]> |
Yes. And it is not unreasonable for a application such as PostGIS to have all the packages as a requirement. Other applications may want to leave that responsibility to the user or simply just require a specific regional packages. /Kristian > On 30 Sep 2019, at 22:34, Paul Ramsey <[email protected]> wrote: > > So, just as a confirmation: being a stupid ape and just blindly installing every datumgrid.zip file I can get my hand on will lead to the “best” results? > >> On Sep 30, 2019, at 1:28 PM, Kristian Evers <[email protected]> wrote: >> >> Yes, this could do with some clarification in the docs. Briefly, it goes something like this: >> >> proj-datumgrid is the original datumgrid packages. It contains mostly basic North American grids, >> a few European grids and the egm96 geoid model. The test suite will fail without this. Many >> transformations will work without it. These days this package is mostly kept for legacy reasons. >> >> The regional grid packages contain grids and other resources that are useful in those regions. >> Currently three regions are covered. The grids are split in these packages to avoid consuming >> too much disk space for users who has that concern. If you have plenty of space just get all of them. >> >> The world package is for grids that has global coverage. Currently only the egm08_25.gtx grid is >> in that package. It is NOT a package containing all grids of the world. >> >> >> We have previously talked about adding a -all package which holds everything. This will be easier >> for most people to use it seems. I haven’t gotten around to it because it requires changing the >> CMake setup of the proj-datumgrids repository [0] and that is just not a job that I am particularly keen >> on doing. A pull requests adding this is welcome. >> >> Finally, Howard is trying to find the funds to deal with grids in a smarter way. I suggest that those >> who can support his effort. >> >> /Kristian >> >> [0] https://github.com/OSGeo/proj-datumgrid >> >> >>> On 30 Sep 2019, at 22:09, Paul Ramsey <[email protected]> wrote: >>> >>> The list of datum grids on the web side is not 100% clear on what grids a person should pull for what purpose… >>> There’s regional files (europe and na and oceania) there’s a “world” file which, by size, perhaps includes all of the above? and there’s the un-specialized file, proj-datumgrid that is… everything not in the other files? something else? >>> >>> >>> • 2018-09-15 proj-datumgrid-1.8.zip >>> >>> • 2019-09-01 proj-datumgrid-europe-1.4.zip >>> >>> • 2019-03-01 proj-datumgrid-north-america-1.2.zip >>> >>> • 2018-03-01 proj-datumgrid-oceania-1.0.zip >>> >>> • 2019-03-01 proj-datumgrid-world-1.0.zip >>> >>> If the best practice is just “download’em’all if you have the space”, then an “all” might be good, instead of “world”. And some note on what proj-datumgrid-1.8.zip actually is? Is it for Proj < 6 only? >>> >>> P >>> _______________________________________________ >>> PROJ mailing list >>> [email protected] >>> https://lists.osgeo.org/mailman/listinfo/proj >> > _______________________________________________ PROJ mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/proj