Re: [Viking-devel] Four more questions about Viking source code

2016-05-03 Thread Greg Troxel

Robert Norris  writes:

> To be honest I don't know what/why/how the use of this 'One Zone' for
> UTM helps anything.

I agree UTM is used less and less as there are fewer maps in UTM (vs
maps that used to be in UTM reprojected into Web Mercator).

When using UTM, you can get awkwardness when the displayed portion
crosses a zone boundary.   It makes sense to decide the zone based on
the center, and then convert all the rest of the screen to/from geodetic
coordinates based on that single zone.This will result in some UTM
coordinates with the wrong zone, basically extended from the next one,
instead of the UTM coordinates you'd get from the geodetic coordinates,
but it should still render ok.  And if a UTM-style TMS-ish source has
tiles in that beyond-the-edge region, it should work ok.

I could well be misunderstanding.




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Re: [Viking-devel] Four more questions about Viking source code

2016-05-03 Thread Robert Norris

> From: acer...@wp.pl
> To: viking-devel@lists.sourceforge.net
> Date: Tue, 3 May 2016 10:48:37 +0200
> Subject: [Viking-devel] Four more questions about Viking source code
>
> Hello,
>
> While working on a copy of Viking I've found few places in code that I
> think may be improved. Can you please take a look?
>

Yes no problem.

Thanks for taking the time to report these issues.

>
> 1.
> src/viktrwlayer.c:2193
>
> g_array_index(dp->vtl->track_gc, GdkGC *, 11)
>
> I think that the value '11' is invalid, because in my builds the
> following message apears in terminal:
> "(viking:3814): Gdk-CRITICAL **: IA__gdk_draw_arc: assertion 'GDK_IS_GC
> (gc)' failed"
>
> Since this line is supposed to draw a stop, perhaps
> VIK_TRW_LAYER_TRACK_GC_STOP should be used instead.
>

Yes definitely - it should be using VIK_TRW_LAYER_TRACK_GC_STOP.

>
> 2.
> src/vikviewport.c:1641
>
> vik_coord_load_from_utm ( &test, VIK_VIEWPORT_DRAWMODE_UTM, &u );
>
> Strictly speaking the second argument to the function should be
> VIK_COORD_UTM. Both names evaluate to zero, so this works.

Yes it should be VIK_COORD_UTM.

>
> 3.
> src/viktrwlayer.c:3324
>
> GHashTable *vik_trw_layer_get_waypoints_iters ( VikTrwLayer *vtl )
> {
> return vtl->waypoints;
> }
>
> Shouldn't this function return vtl->waypoints_iters?
>

Yes it should.

>
> 4.
> src/viktrwlayer.c:2178
> src/viktrwlayer.c:2365
>
> if ( (!dp->one_zone && !dp->lat_lon) ...
>
> Shouldn't these conditions for drawing a trackpoint and a waypoint be
> the same? Currently they are not, second term of each condition is:
>
> ((!dp->one_zone) || tp->coord.utm_zone == dp->center->utm_zone)
> vs.
> ( dp->lat_lon || wp->coord.utm_zone == dp->center->utm_zone )
>
> From my understanding (!dp->one_zone) != dp->lat_lon.
> Am I mistaken?

I agree that is makes more sense for the conditions to be same for trackpoints 
and waypoints.

To be honest I don't know what/why/how the use of this 'One Zone' for UTM helps 
anything.

These lines haven't changed since the first inception of Viking and these extra 
conditions only effect drawing in UTM mode.
(Which I assume is not used much).

I suspect the condition for the waypoint drawing test should be using 
!dp->one_zone.

But in my limited testing it seems to make no difference.

Thus for now I've leave this bit of code as is.

>
> Best regards,
> Kamil
>
  
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