[R-sig-Geo] Plot (image( )) Real RGB Colors of an Imported GeoTIFF (readGDAL( ))

[Rodrigo Aluizio]

Hi List members.

I’m actually able to import a Georeferenced image (.tiff) using readGDAL
{rgdal} and plot it using image {Graphics}.

But the colors options available in the image function (topo.colors,
heat.colors, terrain.colors, etc) aren’t able to adequately reproduce the
original image. The tiff file represent land and ocean, so I need brow and
green tones to land and blue tones to ocean. I was able to create the blue
tones with colorRampPalette () but these blue tones are also applied to the
land.

Once imported the object containing the raster georeferenced file brings
three data columns with bands (RGB maybe) values of each cell (I guess).
Isn’t there a way to reproduce the real colors using these columns
information or any other way to do so?

 

Thank you on advance for the patience and help.

 

Below, some useful information on the object:

 

>
BC<-readGDAL('C:/Users/Rodrigo/Documents/Shapefiles/Campos/BaciaCampos-GE-SA
D69-LongLat.tiff')

C:/Users/Rodrigo/Documents/Shapefiles/Campos/BaciaCampos-GE-SAD69-LongLat.ti
ff has GDAL driver GTiff 

and has 3350 rows and 3015 columns

 

> summary(BC)

Object of class SpatialGridDataFrame

Coordinates:

        min       max

x -42.15808 -39.58503

y -23.74079 -21.08709

Is projected: FALSE 

proj4string : [+proj=longlat +ellps=aust_SA +no_defs]

Number of points: 2

Grid attributes:

  cellcentre.offset     cellsize cells.dim

x         -42.15765 0.0008534147      3015

y         -23.74040 0.0007921499      3350

Data attributes:

     band1            band2            band3      

 Min.   :  0.00   Min.   :  0.00   Min.   :  0.0  

 1st Qu.: 48.00   1st Qu.: 67.00   1st Qu.: 95.0  

 Median : 70.00   Median : 89.00   Median :117.0  

 Mean   : 65.17   Mean   : 83.37   Mean   :117.7  

 3rd Qu.: 76.00   3rd Qu.: 97.00   3rd Qu.:150.0  

 Max.   :255.00   Max.   :255.00   Max.   :255.0

 

Regards

 

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

MSc.  <mailto:r.alui...@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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