hopefully someone can help me.
I've got some slope data in the form of a formal class RasterLayerand by using the command as(slope, 'spatialGridDataFrame'), I've managed to convert it to a large spatialgriddataframe. However when I look at the data frame my variable, the slope angle, is filled with NA values. Though I don't understand as when I plot the grid it displays the slope angles see image. 
How do I make the variable in my spatialgriddata frame represent the slope angles?
This is the formalraster information 
This image is the spatialGridDataFrame infomation
Any suggestions would be appreciated.