[R-sig-Geo] working with a rotated grid of SpatialPolygons

[Waichler, Scott R]

> How about just using high-level maptools?  Following on directly from your
> code, the function elide can rotate the grid polygons:
> 
> library(maptools)
> plot(elide(grdp, rotate = -45), add = TRUE)

Yes, elide should work for my needs.  Thank you for pointing it out!


> Is your data in a real geographic coordinate system, like UTM or is this
> simply a model with no base on the ground:?

The grid has uniform spacing and I can easily define it with the lower left corner at (0,0), and extending to the right and up.  But I want to rotate the grid and convert the points to a geographic coordinate system like UTM (using a georeferenced location for the model grid origin) so that I can plot the grid over a Google Map background.  I know how to do it using the grid package--a rotated viewport for the model grid and relative coordinates within the viewport, but I would like to learn how to do it using and saving actual geographic coordinates for the grid, so that I can use higher level plotting functions.

I think can get there using the wonderful capabilities of elide().

Scott Waichler