search

qgis / QGIS

QGIS is a free, open source, cross platform (lin/win/mac) geographical information system (GIS)
https://qgis.org
GNU General Public License v2.0
10.6k stars 3.01k forks source link

WGS84 Ellipsoid Calculations #18745

Closed qgib closed 3 years ago

qgib commented 10 years ago

Author Name: Antonio Locandro (Antonio Locandro) Original Redmine Issue: 10320

Redmine category:projection_support

I posted this in the developer mailing list but adding it here also

Hi all, in this document http://www.faa.gov/documentLibrary/media/Order/8260.54A.pdf in Appendix 2 there are lots of calculations and algorithms for solving some useful problems when working with non projected data e.g. EPSG 4326

There is also this github repo https://github.com/pkohut/GeoFormulas and http://wired2code.wordpress.com/2010/07/14/wgs84-ellipsoid-calculations/

Apparently they are written in C and I am wondering if maybe QGIS could benefit from it, I would really want to port this to python also but I am still very new to programming to actually achieve this

Anyway I hope someone with more skills than me can review this and maybe see if this can be used for QGIS

For easy references cases covered are here http://www.pkautomation.com/wgs84_geodesic_calc.html

qgib commented 10 years ago

Author Name: Paolo Cavallini (@pcav)

qgib commented 8 years ago

Author Name: Nyall Dawson (@nyalldawson)

QGIS already handles calculations using a preset ellipsoid (check under Project Properties). I'm struggling to understand what is currently missing that this request refers to. Can you give specifics?

qgib commented 8 years ago

Author Name: Antonio Locandro (Antonio Locandro)

Actually it refers to QGIS be able to do some or all of the calculations described in the package geodetically, for example in WGS84. Like given a center and a radius calculate the intercept of a line given point of origin and azimuth. This could be nice to have for advanced editing capabilities using geodetic formulas. But maybe its an edge case and not needed by everyone

qgib commented 7 years ago

Author Name: Giovanni Manghi (@gioman)

josephholler commented 5 years ago

Related to this, I'm wondering if the field calculator distance() function could be extended to support geodesic calculations in linear units set in project properties by the user, much like $length and $perimeter already support, and like the ST_Distance() function in SpatiaLite http://www.gaia-gis.it/gaia-sins/spatialite-sql-4.3.0.html#p13 or the ST_Distance() function with geographies in PostGIS https://postgis.net/docs/manual-dev/ST_Distance.html

github-actions[bot] commented 3 years ago

The QGIS project highly values your report and would love to see it addressed. However, this issue has been left in feedback mode for the last 14 days and is being automatically marked as "stale". If you would like to continue with this issue, please provide any missing information or answer any open questions. If you could resolve the issue yourself meanwhile, please leave a note for future readers with the same problem and close the issue. In case you should have any uncertainty, please leave a comment and we will be happy to help you proceed with this issue. If there is no further activity on this issue, it will be closed in a week.

github-actions[bot] commented 3 years ago

While we hate to see this happen, this issue has been automatically closed because it has not had any activity in the last 42 days despite being marked as feedback. If this issue should be reconsidered, please follow the guidelines in the previous comment and reopen this issue. Or, if you have any further questions, there are also further support channels that can help you.