[R-sig-Geo] Color Ramp on SpatialLines Object

[Rodrigo Aluizio]

Hi List.

I’m preparing  a map for color publication and some colleagues of mine which
participate on this work, asked me to put the bathymetric lines in a color
ramp of deepness (eg.: light blue to dark blue) just to create an didactic
effect.

Well, this bathymetric data are stored in SpatialLinesDataFrame Object
imported from ShapeFiles with the readOGR (package rgdal) function. Here is
a summary of the object:

 

Object of class SpatialLinesDataFrame

Coordinates:

         min       max

r1 -53.01238 -26.92788

r2 -35.74499   7.03177

Is projected: FALSE 

proj4string :

[+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0]

Data attributes:

 OBJECTID_1      OBJECTID            COTA     

 Min.   :   1           Min.   :   1            Min.   :  25  

 1st Qu.: 570       1st Qu.: 570        1st Qu.: 850  

 Median :1139   Median :1139    Median :1900  

 Mean   :1139     Mean   :1139      Mean   :2128  

 3rd Qu.:1708     3rd Qu.:1708      3rd Qu.:3250  

 Max.   :2277      Max.   :2277       Max.   :5750  

                                             

 SHAPE_Leng                     Shape_Le_1                      LAYER     

 Min.   :  0.04632               Min.   :    5079                    4000
: 120  

 1st Qu.:  0.35611             1st Qu.:   39116                 3500   : 119


 Median :  0.61498           Median :   67435              3000   : 103  

 Mean   :  2.58294            Mean   :  279864               3250   :  95  

 3rd Qu.:  1.13124            3rd Qu.:  123223               3750   :  93  

 Max.   :123.74401           Max.   :13320334              2500   :  89  

 
(Other):1658

 

Well I can plot it without any problem in a map with other ShapeFiles
(SpatialPolygonsDataFrame in this case) imported in the same way. With the
Polygons I’m able to color each item with the color I want (eg.:
col=c(‘col1’,’col2’,’etc’)), but I’m not able to do so with the Lines object
(neither with the col=c(‘col1’,’etc’) or the
col=c(colorRampPalette(c(‘initcol’,’endcol’)) function), when I try it the
same way I did with the Polygons, only the first specified color is applied
to all lines and the others are ignored, if I try with the colorRampPalette
function nothing is plotted and I got a lot of warnings (cor especificada
não é nem numérica nem caracter == specified color is not numeric neither
character)

 

So, here is the doubt, is there a way to designate specific colors to each
line of a SpatialLines* Object?

Ps.: I’m using the plot() function to draw the maps (probably a specific
panel variation of sp package).

 

Thank you for your attention, I hope you may help me.

 

-------------------------------------------------------------

MSc.  <mailto:r.aluizio at gmail.com> Rodrigo Aluizio

Centro de Estudos do Mar/UFPR
Laboratório de Micropaleontologia
Avenida Beira Mar s/n - CEP 83255-000
Pontal do Paraná - PR - Brasil

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