Applying geometry to a collection

Question

I have tried to adapt this script but when i use my points for var newft = fg_points.map(mapfunc);

var NDVI_pixels = nut_def_pts.map(mapfunc);

it claims the nut_def_pts.map is 'not a function'. Why would this be?

 //read in the collection, filter it by date and then path which covers all of the Rep of Ireland
var l8 = ee.ImageCollection('LANDSAT/LC08/C01/T1_TOA')
  .filterDate('2017-01-01', '2018-12-31')
  .filter(ee.Filter.or(
    ee.Filter.and(ee.Filter.eq('WRS_PATH', 208),         
                  ee.Filter.eq('WRS_ROW', 22)),
    ee.Filter.and(ee.Filter.eq('WRS_PATH', 208),         
                  ee.Filter.eq('WRS_ROW', 23)),
    ee.Filter.and(ee.Filter.eq('WRS_PATH', 208),         
                  ee.Filter.eq('WRS_ROW', 24)),              
    ee.Filter.and(ee.Filter.eq('WRS_PATH', 207),         
                  ee.Filter.eq('WRS_ROW', 22)),              
    ee.Filter.and(ee.Filter.eq('WRS_PATH', 207),         
                  ee.Filter.eq('WRS_ROW', 23)),              
    ee.Filter.and(ee.Filter.eq('WRS_PATH', 207),         
                  ee.Filter.eq('WRS_ROW', 24)),
    ee.Filter.and(ee.Filter.eq('WRS_PATH', 206),         
                  ee.Filter.eq('WRS_ROW', 23)),
    ee.Filter.and(ee.Filter.eq('WRS_PATH', 206),         
                  ee.Filter.eq('WRS_ROW', 24))));

//specify what bands you want to use to view the image, in this case RGB
var visParams = {bands: ['B4', 'B3', 'B2'], max: 0.3};

//specify where the centre of the map is to be
Map.setCenter(-9, 53, 8);

//view the map using the predefined dataset and bands
//Map.addLayer(l8, visParams, 'l8_mayo collection');

//get the cloud cover information from the QA
var getQABits = function(image, start, end, newName) {
    // Compute the bits we need to extract.
    var pattern = 0;
    for (var i = start; i <= end; i++) {
       pattern += Math.pow(2, i);
    }
    // Return a single band image of the extracted QA bits, giving the band
    // a new name.
    return image.select([0], [newName])
                  .bitwiseAnd(pattern)
                  .rightShift(start);
};

// A function to mask out cloud shadow pixels.
var cloud_shadows = function(image) {
  // Select the QA band.
  var QA = image.select(['BQA']);
  // Get the internal_cloud_algorithm_flag bit.
  return getQABits(QA, 7,8, 'Cloud_shadows').eq(1);
  // Return an image masking out cloudy areas.
};

// A function to mask out cloudy pixels.
var clouds = function(image) {
  // Select the QA band.
  var QA = image.select(['BQA']);
  // Get the internal_cloud_algorithm_flag bit.
  return getQABits(QA, 4,4, 'Cloud').eq(0);
  // Return an image masking out cloudy areas.
};

//run the cloud cover for the images
var maskClouds = function(image) {
  var cs = cloud_shadows(image);
  var c = clouds(image);
  image = image.updateMask(cs);
  return image.updateMask(c);
};

//create the cloud free images
var l8_cfree = l8.map(maskClouds);

//view the cloud free images
//Map.addLayer(l8_cfree, visParams, 'l8_mayo collection without clouds');

//add NDVI as a column to the multispectral bands data
var addNDVI = function(image) {
  //var ndvi = image.normalizedDifference(['B5', 'B4']).rename('NDVI');
  var ndvi = image.select('B5').subtract(image.select('B4')).divide((image.select('B5').add(image.select('B4')))).rename('NDVI');
  return image.addBands(ndvi);
};

//map the landsat collect with the cloud free data and the NDVI band
var withNDVI = l8.map(maskClouds).map(addNDVI);

//view the NDVI images
var ndviParams = {min: -1, max: 1, palette: ['blue', 'white', 'green']};
Map.addLayer(withNDVI.select('NDVI'), ndviParams, 'NDVI image');

//view the NDVI as a time series
var NDVI_ts = ui.Chart.image.series({
  imageCollection: withNDVI.select('NDVI'),
  region: nut_def_pts,
  reducer: ee.Reducer.median(),
  scale: 30
}).setOptions({title: 'NDVI time series'});

// Display the chart in the console.
print(NDVI_ts);

//creates a function that extracts pixel values for NDVI for each point in
//the geom file for each image and writes to a table
var mapfunc = function(feat) {
  var geom = feat.geometry();
  var addProp = function(img, f) {
    var newf = ee.Feature(f);
    var date = img.date().format();
    var value = img.reduceRegion(ee.Reducer.median(), geom, 30).get('NDVI');
    return ee.Feature(ee.Algorithms.If(value,
                                       newf.set(date, ee.String(value)),
                                       newf.set(date, ee.String('No data'))));
  };
  var newfeat = ee.Feature(withNDVI.iterate(addProp, feat));
  return newfeat;
};

var NDVI_pixels = nut_def_pts.map(mapfunc);


//write to the table
Export.table.toDrive(NDVI_pixels,
"NDVI_extraction", //job name
"EarthEngine", //folder name
"NDVI_pixels"); //file name

Answer 1

As Rodrigo pointed out i had to ensure the points were imported as a FeatureCollection