The interface is not very useful in itself... I can now import a raster to the interface after installing the sp and rgdal packages. I would now like to get an analysis of the different values of the raster. An idea of the relative values of the raster, be it via a count, a histogram, a percentage. I have tried the various menus and not much seems to appear. I have the name of the raster visible in the workspace manager window.
It is possible to export the variables of the band as a table *csv and html by right clicking on the band. The resultant table does not however provide me with much information that I find useful.
Ok so after a bit of messing around I have decided to just do some basic R learning... I plot my first graph from a tutorial here. I feel powerful :) I have just created a graph in R... inside QGIS. HOwever it has nothing to do with my spatial data...
How do I reference my imported raster??
I dont know... I try more stuff from the tutorial...
Another tutorial on the basics of R: R Tutorial... I am starting to see the light!
I load a csv table that I created above... using:
- rast = read.csv(file.choose(), header=T)
The table is stored with the variable "rast". To access this table i just type in that variable. The table is also accessible from the workspace browser. That is where the raster was imported to in manageR!
I realise that to do an analysis of data... it needs to be in a format that I at least understand... Which makes sense. I redirect my thoughts to defining the different values of the raster... where does the data get stored with the values for each cell of the raster? I do some looking around... I'm going to try to create a colour table for the raster... I have tried this before without much success... but I have found a good tutorial
After some R practice using the plotvals dataset I understand the interface a bit better and was quickly able to make an R plot within GIS using manageR.
However the original question was the analysis of raster data.
I found an interesting post and tried to load the "maptools" library. it was not installed so I did that.
>library(maptools)
To write the data to a tab delimited excel file:
> locat <- "~/Documents/Stellies/FS 884/Shapefiles/GIS/Correct/Grabouw/output.xls"
> write.table(za1,locat, sep="\t")
