I have created a NDVI time-series map for 5 different years. Now I want to prepare a combined raster band of the 5 years' time interval to form a single combined raster band.
How can this be done in ArcMap?
To create an image composite of five years NDVI data you can use the Composite Bands tool in ArcGIS.
Go to Data Management > Raster > Raster Processing > Composite Bands. Double-click the Composite Bands Tool. For input features, add all NDVI raster layers.
EDIT: I think you want all the raster bands to be in a single band. The Composite Band tool just overlays one layer after another creating a multi-band raster. If you want a single NDVI band, you can use the Cell Statistics tool. The tool uses a particular statistics of each corresponding cells in a composite raster.
You can use the tool to create a mean, sum, median or any other statistical function according to the requirements. You can add the composite raster as the input or just add the NDVI bands as input bands in the tool.