[R-sig-Geo] densify geometries

[Robert J. Hijmans]

geosphere functions makeLine and makePoly do this, but only for
lon/lat, not for planar coordinates.
Robert

On Fri, Aug 7, 2015 at 6:30 AM, Michael Sumner <mdsumner at gmail.com> wrote:
> This is a nice idea with gBuffer, but testing on a simple case shows you
> need explicit curvature to get any extra verts.
>
> library(rgeos)
> library(raster) ## just for the "cheat's" polygon creator
>  x <- as(extent(0, 1, 0, 1), "SpatialPolygons")
> plot(as(as(gBuffer(x, width = 0.1, quadsegs = 55), "SpatialLines"),
> "SpatialPoints"))
>
>
> I want the extra vertices for curvature that's in the space traversed, not
> defined by the segment.
>
> Ultimately we need it to be driven by the right curve (great circle,
> loxodrome, etc.) so geosphere is a good start - but still the simplest case
> of inserting explicitly seems like an obvious gap here (pardon the pun),
> even for GEOS?
>
> Cheers, Mike.
>
>
> On Fri, 7 Aug 2015 at 15:23 chris english <englishchristophera at gmail.com>
> wrote:
>
>> Mike,
>>
>> I use rgeos::gBuffer for polygons akin to what you're seeking. Looking at
>> the implementation of the
>> quadsegs argument might aid you.  Don't know what to suggest for lines
>> though I'm thinking the
>> aggregation process in Trajectories might be of use.  I realize that
>> aggregation suggests reducing
>> rather than densifying but there many be an opportunity to inject
>> arbitrary 'between' points to densify
>> to lines.
>> HTH. Chris
>>
>> On Thu, Aug 6, 2015 at 11:10 PM, Michael Sumner <mdsumner at gmail.com>
>> wrote:
>>
>>> Hello, is there any existing function in the Spatial family in R to
>>> "densify geometries"?
>>>
>>> I'd like to be able specify the insertion of redundant vertices for all
>>> individual segments within a Line* or Polygon*. I've done a bit myself but
>>> wondering if this already exists somewhere.  This is a pretty standard
>>> task
>>> for reprojection in traditional GIS. Ultimately I would implement a
>>> "minimum distance" option as well, just wondering if this is already out
>>> there somewhere.
>>>
>>> I know there are partial pieces of this, for instance in
>>> raster::rasterToPolygons and rgeos::gDistance - are there others? - but I
>>> want more control.
>>>
>>> Cheers, Mike.
>>>
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>>>
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>>
>>
>
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