[Marble-devel] Review Request 123579: UTM grid and coordinates fixed

Tue May 5 21:09:55 UTC 2015

> On May 3, 2015, 10:10 a.m., Dennis Nienhüser wrote:
> > src/lib/marble/geodata/data/GeoDataCoordinates.h, line 380
> > <https://git.reviewboard.kde.org/r/123579/diff/2/?file=365494#file365494line380>
> >
> >     These are not used outside GeoDataCoordinates, right? I'd move them to GeoDataCoordinatesPrivate instead and call them via d->lonLatToUTMString() etc then.

I'm thinking about reordering all the UTM-related code. My idea is: delete all `{lon,lat,lonLat}ToUTMString()` I've done and implement four main functions for obtaining the four main values of UTM (zone, latitude band, easting and northing). These four functions would be implemented based on all the mathematical stuff that was placed in GeoDataUTM. Hence, we can move all those mathematical functions to GeoDataCoordinatesPrivate and make them static as you suggested in the other issue.

Futhermore, the four main functions should have two versions: one static and one non-static. My idea es: implement them in GeoDataCoordinatesPrivate as static (maybe something like `lonLatToZone(qreal lon, qreal lat)`, `lonLatToLatitudeBand(qreal lon, qreal lat)`, ...) and then declare the other version in GeoDataCoordinates (they could maybe named just `zone()`, `latitudeBand()` and so on). The idea behind making a public non-static version is just to give the possibility of obtaining the UTM values from a GeoDataCoordinates object, as it is possible now for the lon/lat units with `longitude()` or `latitude()`. It's not critical but I think it could help to improve the coordinate system support.

Implementing the static versions is mandatory if we want to use them from lonToString and latToString (which are static). However, these two functions need a bigger refactoring as you said in another issue, as this proposal does not solve the real problem: we have to guess the UTM values from just one component of the pair (lon,lat), when we really need both of them.

If you think this is a good way to advance, I can finish this implementation (I have it nearly done) and update the review request. And, please, feel free to comment anything you does not like.

Thank you! :)

- Alejandro

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On May 2, 2015, 6:57 p.m., Alejandro García Montoro wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/123579/
> -----------------------------------------------------------
> 
> (Updated May 2, 2015, 6:57 p.m.)
> 
> 
> Review request for Marble.
> 
> 
> Repository: marble
> 
> 
> Description
> -------
> 
> Two different tasks have been accomplished concerning UTM coordinate system:
> 
> 1. The UTM grid rendering has been fixed. Now the grid and labels are drawn as expected (see http://upload.wikimedia.org/wikipedia/commons/e/ed/Utm-zones.jpg for comparison)
> 2. Some UTM functions have been added in order to properly calculate and display the coordinates on the status bar. Those functions have been wrapped in the new GeoDataUTM namespace inside GeoDataCoordinates.cpp If you prefer to see the functions integrated in the GeoDataCoordinates class, please, let me know.
>  
> **Still to be fixed**: The UTM string showed in the status bar is too long for the text field in which it is shown. I have not been able to change its size, as I have not found the relevant .ui file; where in the code should I check to change that?
> 
> **Note**: The lat/lon <-> UTM conversion algorithm has been adapted from this JavaScript code http://home.hiwaay.net/~taylorc/toolbox/geography/geoutm.html. The author says in the page "The JavaScript source code in this document may be copied and reused without restriction", and I have linked the website in the code. However, as I am not sure about all the licenses and authoring stuff, I would like you to review it.
> 
> 
> Diffs
> -----
> 
>   src/apps/marble-kde/marble_part.cpp 283ad87a39f91e01c391a4dd8f4c9ddbeef41481 
>   src/apps/marble-qt/QtMainWindow.cpp c4280c62b4534b7d10387b6895d142920f957bb7 
>   src/lib/marble/geodata/data/GeoDataCoordinates.h 6efabd047f8f3aff63381facb78cb371c0740bf4 
>   src/lib/marble/geodata/data/GeoDataCoordinates.cpp fe74a2e42db921b152a29ef04246ceaaa16c2325 
>   src/plugins/render/graticule/GraticulePlugin.cpp a5e6d14a921c66d55cf01e39b16564dedcf6532b 
> 
> Diff: https://git.reviewboard.kde.org/r/123579/diff/
> 
> 
> Testing
> -------
> 
> Changes tested in master branch @ 1st May.
> Grid and coordinates work well (except for the displaying issue explained above) and are consistent with the UTM coordinate system.
> 
> 
> File Attachments
> ----------------
> 
> UTM grid exceptions around Norway
>   https://git.reviewboard.kde.org/media/uploaded/files/2015/05/01/505df756-87f2-47bb-a6c1-d5b52629547a__NorwayScreenshot.png
> 
> 
> Thanks,
> 
> Alejandro García Montoro
> 
>

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