1

I'm trying to classify NAIP imagery for HUC0801 subregion using random forest classifier on GEE.

var water = /* color: #003dd6 */ee.FeatureCollection(
        [ee.Feature(
            ee.Geometry.Point([-89.77880711922072, 35.77516614372526]),
            {
              "LC": 0,
              "system:index": "0"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.6957230127754, 35.79605417549729]),
            {
              "LC": 0,
              "system:index": "1"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.32132424310237, 35.72441548641423]),
            {
              "LC": 0,
              "system:index": "2"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.20658301966641, 35.71620147983874]),
            {
              "LC": 0,
              "system:index": "3"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.17112199599988, 35.69422952164938]),
            {
              "LC": 0,
              "system:index": "4"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.07497245212244, 35.68920813448804]),
            {
              "LC": 0,
              "system:index": "5"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.8463379266921, 35.68473167174959]),
            {
              "LC": 0,
              "system:index": "6"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.84350615349292, 35.68599662392148]),
            {
              "LC": 0,
              "system:index": "7"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.72815052861881, 35.647747724351476]),
            {
              "LC": 0,
              "system:index": "8"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.72727267449217, 35.64407864998295]),
            {
              "LC": 0,
              "system:index": "9"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.72167692150965, 35.63229583998486]),
            {
              "LC": 0,
              "system:index": "10"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.15503144021831, 35.488690451296556]),
            {
              "LC": 0,
              "system:index": "11"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.15864916744249, 35.48621924444361]),
            {
              "LC": 0,
              "system:index": "12"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.20729961346346, 35.50199071525465]),
            {
              "LC": 0,
              "system:index": "13"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.2222590639712, 35.50967786008748]),
            {
              "LC": 0,
              "system:index": "14"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.29663712988093, 35.47670373082221]),
            {
              "LC": 0,
              "system:index": "15"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.35643912829886, 35.45594796661757]),
            {
              "LC": 0,
              "system:index": "16"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.24539255774611, 35.38898565131322]),
            {
              "LC": 0,
              "system:index": "17"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.96370057042756, 36.23184732630431]),
            {
              "LC": 0,
              "system:index": "18"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.0770205752653, 36.27354920070623]),
            {
              "LC": 0,
              "system:index": "19"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.01798461755284, 36.383763269817216]),
            {
              "LC": 0,
              "system:index": "20"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.6345629357191, 36.4454911242644]),
            {
              "LC": 0,
              "system:index": "21"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.4347827664095, 36.43859537979183]),
            {
              "LC": 0,
              "system:index": "22"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.59172848728244, 36.25293981790439]),
            {
              "LC": 0,
              "system:index": "23"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.63267792702267, 36.26079740190436]),
            {
              "LC": 0,
              "system:index": "24"
            })]),
    riparian = /* color: #98ff00 */ee.FeatureCollection(
        [ee.Feature(
            ee.Geometry.Point([-89.44225414985786, 35.53955223803894]),
            {
              "LC": 1,
              "system:index": "0"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.32307495072952, 35.66054547775215]),
            {
              "LC": 1,
              "system:index": "1"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.89819406874301, 36.619508302264094]),
            {
              "LC": 1,
              "system:index": "2"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.70268838236554, 36.44424969773752]),
            {
              "LC": 1,
              "system:index": "3"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.13061438726855, 35.94598128024016]),
            {
              "LC": 1,
              "system:index": "4"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.0092790557817, 35.667661574012776]),
            {
              "LC": 1,
              "system:index": "5"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.04848437911049, 35.38707402518666]),
            {
              "LC": 1,
              "system:index": "6"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.31328921448181, 35.77553921537374]),
            {
              "LC": 1,
              "system:index": "7"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.65070057020814, 35.31036090188487]),
            {
              "LC": 1,
              "system:index": "8"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.40214903746934, 35.05153508702478]),
            {
              "LC": 1,
              "system:index": "9"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.73028482225335, 35.1754873249236]),
            {
              "LC": 1,
              "system:index": "10"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.89441909566804, 35.20694571831696]),
            {
              "LC": 1,
              "system:index": "11"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.92119827047273, 35.2144492934566]),
            {
              "LC": 1,
              "system:index": "12"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.2439111192682, 35.27378436859066]),
            {
              "LC": 1,
              "system:index": "13"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.09345795254362, 35.32586405437563]),
            {
              "LC": 1,
              "system:index": "14"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.77842921934243, 35.58418661604577]),
            {
              "LC": 1,
              "system:index": "15"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.72590113877084, 35.601989406115614]),
            {
              "LC": 1,
              "system:index": "16"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.77490870165946, 36.11009435295949]),
            {
              "LC": 1,
              "system:index": "17"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.9873488707638, 36.161935387195875]),
            {
              "LC": 1,
              "system:index": "18"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.12299577997898, 36.25813745850283]),
            {
              "LC": 1,
              "system:index": "19"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.96090010054154, 36.19987172486153]),
            {
              "LC": 1,
              "system:index": "20"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.9435156596092, 36.19442097074415]),
            {
              "LC": 1,
              "system:index": "21"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.93269049989028, 36.20725993703776]),
            {
              "LC": 1,
              "system:index": "22"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.93266212377455, 36.77440663346662]),
            {
              "LC": 1,
              "system:index": "23"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.85852761929496, 36.73460314872616]),
            {
              "LC": 1,
              "system:index": "24"
            })]),
    vegetation = /* color: #228b1e */ee.FeatureCollection(
        [ee.Feature(
            ee.Geometry.Point([-89.00972387654174, 34.99624601121268]),
            {
              "LC": 2,
              "system:index": "0"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.02030120781365, 34.99166459535381]),
            {
              "LC": 2,
              "system:index": "1"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.95126973444123, 34.978095614654904]),
            {
              "LC": 2,
              "system:index": "2"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.75932997809355, 34.97593145276492]),
            {
              "LC": 2,
              "system:index": "3"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.05920462819516, 34.87317526710538]),
            {
              "LC": 2,
              "system:index": "4"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.09721168373186, 34.876475240764556]),
            {
              "LC": 2,
              "system:index": "5"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.13304777346328, 34.87835308142907]),
            {
              "LC": 2,
              "system:index": "6"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.74076386349184, 34.86535119064159]),
            {
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              "system:index": "7"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.6942920695147, 34.86336149181434]),
            {
              "LC": 2,
              "system:index": "8"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.53991702659775, 35.479212337751214]),
            {
              "LC": 2,
              "system:index": "9"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.82465295693675, 35.44904387104237]),
            {
              "LC": 2,
              "system:index": "10"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.58449857558239, 35.09529727355934]),
            {
              "LC": 2,
              "system:index": "11"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.52239979733876, 35.085921631725064]),
            {
              "LC": 2,
              "system:index": "12"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.54037037429323, 35.10504593816796]),
            {
              "LC": 2,
              "system:index": "13"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.50518278100186, 35.126754727816426]),
            {
              "LC": 2,
              "system:index": "14"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.3829101912007, 35.153035290963494]),
            {
              "LC": 2,
              "system:index": "15"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.38770690158888, 35.28401335739074]),
            {
              "LC": 2,
              "system:index": "16"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.30334116564514, 35.33411376088241]),
            {
              "LC": 2,
              "system:index": "17"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.1992577599112, 35.39379891257597]),
            {
              "LC": 2,
              "system:index": "18"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.33871917771734, 35.57786641990827]),
            {
              "LC": 2,
              "system:index": "19"
            }),
        ee.Feature(
            ee.Geometry.Point([-88.68642305486082, 35.83061874446985]),
            {
              "LC": 2,
              "system:index": "20"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.28156972169462, 35.152688933593474]),
            {
              "LC": 2,
              "system:index": "21"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.29251464699644, 35.13583223935476]),
            {
              "LC": 2,
              "system:index": "22"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.10420211647886, 35.15674661163777]),
            {
              "LC": 2,
              "system:index": "23"
            }),
        ee.Feature(
            ee.Geometry.Point([-89.02023701673915, 35.16316081861669]),
            {
              "LC": 2,
              "system:index": "24"
            })]);


//////////////////////////////////////////////////////////////////////////

 // Create the HUC geometry (study area)
var geometry = ee.FeatureCollection('USGS/WBD/2017/HUC04')
    .filter("huc4 == '0801'"); // 08010210 (Wolf)


// Function for clipping image
var clipcol = function(image) {
  var clipimage = image.clip(geometry)
  return clipimage
}

// Import of NAIP-Orthofoto
var dataset = ee.ImageCollection('USDA/NAIP/DOQQ')
                  .filter(ee.Filter.date('2018-01-01', '2018-12-31'))
                  .filterBounds(geometry)
                  .map(clipcol)

// 2nd image              
var listOfImages = dataset.toList(dataset.size());
var orthofoto = ee.Image(listOfImages.get(1))

// True Color Visualisation
var trueColor = dataset.select(['R', 'G', 'B']);
var trueColorVis = {
  min: 0.0,
  max: 255.0,
};
Map.addLayer(trueColor, trueColorVis, 'Orthofoto');

// Band selection and merge of the 3 FeatureCollection
var bands = ['R', 'G', 'B', 'N'];
var merged_collection = water.merge(riparian).merge(vegetation)

// Sample Regions 
var training = orthofoto.sampleRegions({
  collection: merged_collection,
  properties: ['landcover'],
  scale: 1
})

var classifier = ee.Classifier.smileRandomForest(10).train({
  features: training,
  classProperty: 'landcover',
  inputProperties: bands
})

var classified = dataset.select(bands).classify(classifier)
Map.addLayer(classified, {min:0, max:2, palette: ['green','red','blue']},
"classified image")

(Please scroll past all the point geometries, my code is at the bottom of the code block) This is what I have in my code. The error I'm getting is "Line 75: dataset.select(...).classify is not a function" which corresponds to this line;

var classifier = ee.Classifier.smileRandomForest(10).train({
  features: training,
  classProperty: 'landcover',
  inputProperties: bands
})
3
  • 1
    water, riparian and vegetation objects are not available. Please share them as public assets or include its definition in the script. Jun 20, 2022 at 17:41
  • Thank you, those are just training sample points I have created. I'm happy to share, but not sure how I can embed them to the script, or share them individually. I'll update as soon as I figure it out.
    – puredata
    Jun 20, 2022 at 17:59
  • I think I was able to add them to my script. Please let me know if it doesn't work.
    – puredata
    Jun 20, 2022 at 18:51

1 Answer 1

3

The problem is that you are trying to apply certain ee.Image methods to ee.ImageCollection objects, so the error message is telling you exactly that (... is not a function). The first step to fix the script should be mosaicking or reducing the image collection to obtain an ee.Image object (here I used a median reducer). After doing this, you can create the training dataset according to this image, using the merged_collection ee.FeatureCollection. The property in your FeatureCollection is named 'LC', not 'landcover', so also I added that change to your script. Finally, you just need to make the predictions on the complete orthofoto image to obtain your classification. Here are the only changes I made to your script:

var orthofoto = dataset.median();

var training = orthofoto.sampleRegions({
  collection: merged_collection,
  properties: ['LC'],
  scale: 1
})

var classified = orthofoto.classify(classifier)
3
  • Thanks a lot, may I ask you how were you able to check the property? (landcover vs LC). When I made the changes, I ended up getting the error "Cannot read properties of null (reading 'wpa')" . Would you have any suggestions to investigate this error?
    – puredata
    Jun 20, 2022 at 21:28
  • 1
    In the script defining the training points location (water object) you can see that each feature has only two properties: 'LC' and 'system:index'. Since the latter is like an ID for each feature, I assumed 'LC' was the property for landcover. Regarding the error you mention, I would check if the object, from which certain properties are being read, exists or is not empty. Jun 20, 2022 at 22:12
  • 1
    Thanks a lot for your time and help Jonathan, much appreciated!
    – puredata
    Jun 20, 2022 at 22:22

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