[R-sig-Geo] Marginless plot output for georegistration of output graphics

[Edzer J Pebesma]

David Forrest wrote:

>On Wed, 17 Jan 2007, Roger Bivand wrote:
>...
>  
>
>>>What do I need to to do turn the key off for spplot(SpatialPointsData) ?
>>>      
>>>
>>I can't see it, I thought it might be auto.ket=FALSE, but it doesn't seem
>>to be that. To be honest, I would feel more comfortable with base
>>graphics and setting my own class intervals and colours. Lattice graphics
>>seem more worth the trouble when conditioning, which isn't the case here.
>>    
>>
>
>Hmm.  I was thinking that the spplot() was the best-practices method for 
>spatial data.
>
spplot lets you choose class intervals and colours, but in a different 
way than base graphics do. I don't think there is a  best-practices for 
spatial data, in the end  best practice to me is that a plotting engine 
does not leave its traces in the plot. However, R has two plotting 
routes, base and lattice/grid, and sp provides (hopefully) convenient 
wrapper functions to use either. Lattice then has the added (major) 
advantage of auto-legends/classes (to some extent) and conditioning.

>
>  
>
>>The aspect doesn't seem happy yet, and for NA and projected CRS, you get
>>"iso" back instead of the aspect from mapasp.
>>    
>>
>
>Is this a criticism of spplot() or the resultant png from the previous?
>
I believe that spplot'ing SpatialPointDataFrames does call mapasp to set 
its aspect, just like the other ones.

I agree that not having a way to suppress the key in spplot for 
SpatialPointsDataFrame is an omission. I'll try to get the auto.key = 
FALSE working. There's quite some code in sp for this particular method, 
as xyplot (which it wraps) doesn't automatically classify points given 
an attribute value; the extra work is done in sp here, unlike the other 
spplot methods that wrap levelplot.
--
Edzer