I am currently making a landcover change map for a Kinabatangan, Sabah, Borneo for my undergrad dissertation. I downloaded landsat MSS and 8 images. These were pre-processed and both classified using unsupervised isodata classifications. Due to the restricted resolution I had to then use Google Earth Pro to delineate and map palm oil concessions (large palm oil sites) and smallholders (small farmers). I made polygons for each type and converted these to KML for GIS. These polygons were then changed to raster format so everything was the same. Both rasters were combined to make one palm oil layer. I standardised all the data e.g. all had the same projected coordinate system and cell size.
What I can't figure out though is how to combine my palm oil raster data with my 2014 landcover map (this was the only year the palm oil was seen). I essentially want three maps
1) 1973 Base landcover map, with these classes: Water; Forest and Non-forest
2) 2014 landcover map with combined palm oil data, with these classes: Water; Forest; Non-forest; Smallholders; Large Concessions
3) 1973 - 2014 Landcover change map, with these classes: Water; Forest; Non-forest; Smallholders; Large Concessions.
I have tried to use the raster calculator and also merge to new raster tools. Any comments of what I can do / am already doing wrong would be appreciated! P.S. I have attached some pictures of what I am working on [1: Overview of map; 2: Overview of classes].