Re: [Openev-discuss] OpenEV layer display rules

[Frank W. <war...@po...>]

On 12/19/05, Tommi Rouvali <to...@ro...> wrote:
>
> Hello,
> Newbie posting first post here.. :-)
>
> I looked OpenEV and started wondering, does it support display rules for
> layers?
> What I mean is that if I have 1:200 000, 1:500 000 and 1:1 000 000
> raster maps from same area,  I could define which map to show, based on
> zoom level. Now OpenEV seems to redraw all maps when I zoom or move.

Tommi,

I don't believe there is any built-in support for scale-dependent
visibility control.  You could write a script that is called whenever
the view changes, and it could reset layer visibility flags based
on the current zoom level (scale).   But this is at least a bit tricky.

Another approach might be to build a single TIFF file for the 1:200000
data, and then attach the 1:500000 and 1:1000000 data as overviews.
However, you would have to do some fancy processing to accomplish
this if the original boundaries were not the same.

> Also, I would like to connect GPS to open OpenEV, can someone hint me
> where to find source/tips for this?

You might want to look into PyGPS from Russell Nelson.

   http://pygps.org/#pygps

I haven't tried it myself.

Best regards,
--
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam@pobox.c=
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