CODEWITHSUNDEEP
code-editorgoogle-earth-engine
Andrew Stratton
Andrew Stratton

Reputation: 61

Using GEE code editor to create unique values list from existing list pulled from feature

I'm working in the Google Earth Engine code editor. I have a feature collection containing fires in multiple states and need to generate a unique list of states that will be used in a selection widget. I'm trying to write a function that takes the list of state values for all fires, creates a new list, and then adds new state values to the new unique list. I have run the code below and am not getting any error messages, but the output is still statesUnique = []. Can anyone point me in the right direction to get the new list to populate with unique values for states?

My Code:

// List of state property value for each fire
var states = fire_perim.toList(fire_perim.size()).map(function(f) {
  return ee.Feature(f).get('STATE');
}).sort();
print('States: ', states);

// Create unique list function
var uniqueList = function(list) {
  var newList = []
  var len = list.length;
  for (var i = 0; i < len; i++) {
    var j = newList.contains(list[i]);
    if (j === false) {
      newList.add(list[i])
    }
  }
  return newList
};

// List of unique states
var statesUnique = uniqueList(states);
print('States short list: ', statesUnique)

Upvotes: 3

Views: 1475

Answers (1)

Andrew Stratton
Andrew Stratton

Reputation: 61

Okay, I did not come up with this answer, some folks at work helped me, but I wanted to post the answer so here is one solution:

var state_field = 'STATE'
var all_text = 'All states'
// Function to build states list
var build_select = function(feature_collection, field_name, all_text) {
  var field_list = ee.Dictionary(feature_collection.aggregate_histogram(field_name))
                     .keys().insert(0, all_text);
  return field_list.map(function(name) {
    return ee.Dictionary({'label': name, 'value': name})
  }).getInfo();
};

var states_list = build_select(fire_perim, state_field, all_text)
print(states_list)

Upvotes: 3

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