On Wednesday 09 January 2008 00:24, Adam Dershowitz wrote:
> On Jan 7, 2008, at 7:15 PM, LeeE wrote:
> > On Monday 07 January 2008 22:28, Curtis Olson wrote:
> >> On Jan 7, 2008 3:51 PM, Frederic Bouvier <> wrote:
> >>> If we keep the same triangle budget for every tile, we will
> >>> have sparse d
On Jan 7, 2008, at 7:15 PM, LeeE wrote:
> On Monday 07 January 2008 22:28, Curtis Olson wrote:
>> On Jan 7, 2008 3:51 PM, Frederic Bouvier <> wrote:
>>> If we keep the same triangle budget for every tile, we will
>>> have sparse data and
>>> features at the equator and much more than what is real
Frederic Bouvier wrote:
> Selon Ralf Gerlich :
>
>
>> The alternative would be to scale the number of vertices passed to
>> TerraFit by cos(lat)...
>
> I was thinking of this solution : regular lon/lat tile scheme but variable
> number of resulting vertices per tile.
That's what I meant ;-)
--
Ralf Gerlich wrote:
> Currently we have tile borders that are representable as polygon - more
> strictly as rectangles - which makes clipping easy. The new tile borders
> could not be well-approximated using polygons. We could try creating
> clipping polygons that approximate the borders down to an
Selon Ralf Gerlich :
> The alternative would be to scale the number of vertices passed to
> TerraFit by cos(lat)...
I was thinking of this solution : regular lon/lat tile scheme but variable
number of resulting vertices per tile.
-Fred
--
Frédéric Bouvier
http://frfoto.free.fr
Hi!
Curtis Olson wrote:
> On Jan 8, 2008 1:22 AM, Frederic Bouvier <> wrote:
>
> I was thinking about the parameter we pass to "Terra" to simplify the
> initial grid. IIRC, this parameter is always the same, leaving all
> *.arr.gz files with the same number of vertices.
>
>
> Yes, that's a good
On Jan 8, 2008 1:22 AM, Frederic Bouvier <> wrote:
> I was thinking about the parameter we pass to "Terra" to simplify the
> initial
> grid. IIRC, this parameter is always the same, leaving all *.arr.gz files
> with
> the same number of vertices.
>
Yes, that's a good point, and something definite
LeeE wrote:
> Yup - I downloaded lots of SRTM data to play with in GRASS and
> above/below +/- 60 lat it isn't there.
>
> There doesn't seem to be any alternative source of suitable data
> either so I don't see how FG can cover the poles.
FG can cover the poles - and has been doing so for years
Hi!
Frederic Bouvier wrote:
> Selon Curtis Olson :
>> My gut feeling is that once you get up (or down) into the latittudes where
>> the tiles get significantly skinny, the resolution of the available data
>> drops of significantly. We really don't have a per-tile triangle budget
>> anyway. The o
Selon Curtis Olson :
> On Jan 7, 2008 3:51 PM, Frederic Bouvier <> wrote:
>
> > If we keep the same triangle budget for every tile, we will have sparse
> > data and
> > features at the equator and much more than what is really needed at the
> > poles,
> > just because the area covered by each tile
On Monday 07 January 2008 22:28, Curtis Olson wrote:
> On Jan 7, 2008 3:51 PM, Frederic Bouvier <> wrote:
> > If we keep the same triangle budget for every tile, we will
> > have sparse data and
> > features at the equator and much more than what is really
> > needed at the poles,
> > just because
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Curtis Olson wrote:
> My gut feeling is that once you get up (or down) into the latittudes where
> the tiles get significantly skinny, the resolution of the available data
> drops of significantly. We really don't have a per-tile triangle budget
> a
On Jan 7, 2008 3:51 PM, Frederic Bouvier <> wrote:
> If we keep the same triangle budget for every tile, we will have sparse
> data and
> features at the equator and much more than what is really needed at the
> poles,
> just because the area covered by each tile will vary greatly (
> proportional
Selon Curtis Olson :
> I've been wondering about dispensing with the variable subdivision scheme
> and just having a fixed number of divisions per 1 degree of longitude.
> Perhaps having 4 subdivisions. This would double the tile width at the
> equator, but would preserve the same tile widths in
On Jan 7, 2008 5:10 AM, Ralf Gerlich <[EMAIL PROTECTED]> wrote:
> Thinking a bit more about it, the grid could be made consistent if we
> would define that 180W and 180E are tile borders instead of enforcing
> the Greenwich Meridian to be a tile border at all ranges of latitude.
>
> Find attached
Hi again!
Thinking a bit more about it, the grid could be made consistent if we
would define that 180W and 180E are tile borders instead of enforcing
the Greenwich Meridian to be a tile border at all ranges of latitude.
Find attached my proposed patch.
That would change the arrangement of tiles
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