#550 MAP is not Nort Pole compatible

[Anonymous]

Originally created by: Harry131...@gmail.com
Originally owned by: gijsrooy

The internal MAP will cause FG to crash if too near the North Pole.

Park the aircraft at Alert, open Instruments=>MAP, zoom out, poof.

Running the 20111219 snapshot.

I suspect it's data overload. Since MAP also can cause a crash when zooming out due to data overload I suggest to perform a data count after zoom, before draw and set a limit on that reporting an error preventing a FG crash.

I know MAP is experimental and I'm beginning to like it. One thing missing is elevation of the runway. The cursor control is also weird.

[Anonymous]

Originally posted by: gijsrooy

Reproducable with today's Git. Zooming isn't the issue, just panning up north (till you "see" the north-pole) with zoom-level 12 also crashes. It just flips when it needs to draw two sides of the earth :)

Note: Alert is the world's northernmost permanent airport (CYLT) ;)

Labels: NavDat GUI
Cc: zakalawe@mac.com
Status: Accepted

[Anonymous]

Originally posted by: gijsrooy

FlightGear does not crash here btw. It "just" hangs for a couple of minutes. Once the north pole is "loaded", it only hangs for a couple of seconds when re-centering the map on the north pole (after panning around a little).

[Anonymous]

Originally posted by: zakalawe@mac.com

Hmm, the problem is the projection code, borrowed from Atlas. This needs more thought to handle the poles correctly. BTW, runway threshold elevation should be included already, if not, I'll add it.

[Anonymous]

Originally posted by: Harry131...@gmail.com

@Zakalawe I could not find elevation on 2.6.0 RC1. Could find RW length. Getting to like the map more and more.

[Anonymous]

Originally posted by: johannes...@googlemail.com

This is true for the South Pole, either.  (There are other issues related to that, too)
Maybe another projection method for the polar regions need to be used.

[Anonymous]

Originally posted by: zakalawe@mac.com

Right, the current project doesn't handle the poles well. I'm not a cartographic expert, but the projection model is easy to change, if anyone can suggest one that handles the poles nicely.

[Anonymous]

Originally posted by: zakalawe@mac.com

Still need a better projection model than Samsom-Flamsteed near the poles, but this may also change when I switch the Map to use the canvas (although I think Thomas copied my projection code)

Status: NeedInfo

[Anonymous]

Originally posted by: tom...@gmail.com

Yes, the Canvas currently only uses basically the same projection as used in the MapWidget. But the interfaces are designed in a way such that it should be very easy to plug in different projections.

See eg. https://gitorious.org/fg/simgear/blobs/next/simgear/canvas/elements/map/projection.hxx#line139 how the Sanson-Flamsteed projection is implemented.

I'm also not a cartographic expert but eg. in ARINC661 Lambert and Polar projection are mentioned. Also it seems that there is no projection which covers all areas well so we maybe will need to set up a system which allows to switch the projection depending on the center coordinates of the map.

[Anonymous]

Originally posted by: pedromor...@gmail.com

(No comment was entered for this change.)

Labels: Map GeoSpatial

[Anonymous]

Originally posted by: gijsrooy

From what I've read, real world navigation displays use some form of Azimuthal equidistant projection

http://en.wikipedia.org/wiki/Azimuthal_equidistant_projection
http://www.google.com.tr/patents/US7933716

Labels: -Map -GeoSpatial
Cc: gijsrooy

[Anonymous]

Originally posted by: gijsrooy

Issue 1321 has been merged into this issue.

[Anonymous]

Originally posted by: gijsrooy

I've managed to implement the azimuthal equidistant projection for both the map dialog and the Canvas maps. It looks very nice on the ND/map (straight lines to follow when you fly a direct route, rather than arcs). And best of all, no more weird lines around the world when drawing a route accross the datum line. See attached images for PANC - > UHPP route.

There are several issues that I'll investigate tomorrow or next week. I'll share my code when I fail to fix them, or when I've managed to fix them :-)

To list a few:

- The route manager doesn't seem to support polar flights. FlightGear segfaults when I try to plan a route from E001N89 to E179N89, or from BIKF to PANC. That's irregardless whether I'm using the old or new projection.
- The map with my projection doesn't react to mouse pan.
- The latitude/longitude lines are drawn incorrectly (no update when the map center changes).
- Fixes, airports etc. aren't always shown.
- The aircraft icon isn't shown when we're not moving.

Labels: -NavDat Canvas-navdisplay
Owner: gijsrooy
Cc: -gijsrooy h...@hyde-tech.com tom...@gmail.com
Status: Dev

[Anonymous]

Originally posted by: zakalawe@mac.com

Nice work, please send me some info on the crash and I'll look at that ASAP since it should be fixed for 3.0

Reacting to mouse requires an implementation of 'unproject', same for latitude / longitude lines. But likely the whole approach to lat/lon grid drawing needs to be re-considered for polar projections.

No idea which fix/airport/aircraft icons are being erratic, should be totally separate.

As a more general point, isn't there a plan to replace the whole dialog with a Canvas implementation 'soon'?

[Anonymous]

Originally posted by: gijsrooy

Issue 454 has been merged into this issue.

[Anonymous]

Originally posted by: gijsrooy

James, did you find some time to take a quick look at the patch I sent you?

[Anonymous]

Originally posted by: zakalawe@mac.com

Didn't get a chance to review the patch yet, but it's in my queue, I promise.

[Anonymous]

Originally posted by: zakalawe@mac.com

Gijs' patch merged in commit [r3f433e2c35ef533a847138e6ae10a5cb398323d7]

Status: Fixed

[Anonymous]

Originally posted by: gijsrooy

Nice, thanks James (for correcting my errors)!

Labels: Milestone-3.2