I have a composite with four bands NIR, Red, Green and Blue. I would like help on which weight values to use when converting it to a single band which will then be used to classify vegetation. I am using Image Analysis in ArcGIS.
You may not have a background in the principles of remote sensing.
There are many existing vegetation indices, such as the most simple and common NDVI, that do what you are asking. Generally you should have an idea what index you are going to use based on the objectives of your analysis. Before you create an index, it's also best practice to convert DNs to reflectance before any subsequent image processing. Atmospheric correction is not strictly necessary if you are only using one image, but if you don't perform atmospheric correction, your results won't be comparable to scenes from other locations or dates.