Creating cloud free imagery and applying NDVI calculation to NAIP, Sentinel 2, and L8 collections using Google Earth Engine?

Question

I'm trying to get cloud and shadow-free (or as close to cloud free) scenes for Landsat 8, NAIP, and Sentinel 2 (specifically sentinel 2 10 meter resolution), and then apply the NDVI calculation to each set.

After that, I'd like to look at those values within specific polygon geometries I've created, but that's a separate thing I'd like to try on my own first!

I'm fairly new to GEE, and though I've watched the tutorials I still have some trouble with basic things it seems.

Here is just the portion I have so far for Landsat 8, though it's not running error-free.

// add three imagery layers to neighborhoods and filter date
var l8filtered = landsat8.filterDate('2016-10-01', '2016-10-31'); 
                         .sort('CLOUD_COVER');
                         .first());

// send to console/add to map
print(l8filtered, "l8 filter")
Map.addLayer(l8filtered,{},"L8")

//create NDVI image
var l8_ndvi = l8filtered.normalizedDifference(['B5','B4']);
Map.addLayer(l8_ndvi,{min:-0.1, max:0.1, palette:['FFFFFF', '339900']},'L8 NDVI');

For the cloud shadow - I've been sleuthing a did come across this post, however it's not quite making sense to me.

For the Landsat 8 imagery specifically - am I right in defining the bands in the l8_ndvi variable, or should I be calling the bands out before that?

Answer 1

I have finished this! Here's the link to the code if anyone is curious: https://code.earthengine.google.com/64f258f80593984dc9ed946dba11a8ab

I had trouble clipping the calculations to my geometry layer at first, and also realized that the cloudmask and ndvi functions I had in there were trying to go off of an Image vs. an ImageCollection like I had for L8 and S2 data.