How to get fields in StylePluginBase
Normally you would iterate through the rows and call a row plugin to render the field values. As I understand the question you want to access the field values directly by row index and field id?

Then try StylePluginBase::getFieldValue:

$value = $this-&gt;getFieldValue($index, $field);




Normally a style plugin iterates the rows like this:

  public function render() {
    if (empty($this-&gt;view-&gt;rowPlugin)) {
      trigger_error('Missing row plugin', E_WARNING);
      return [];
    }
    $rows = [];

    foreach ($this-&gt;view-&gt;result as $row_index =&gt; $row) {
      $this-&gt;view-&gt;row_index = $row_index;
      $rows[] = $this-&gt;view-&gt;rowPlugin-&gt;render($row);
    }
    ...


For this to work you have to set protected $usesRowPlugin = TRUE; and configure a row plugin which renders the map.



If you want to do all rendering in the style plugin you can use the same loop and get the field values directly:

  public function render() {
    $rows = [];
    foreach ($this-&gt;view-&gt;result as $index =&gt; $row) {
      $rows[] = render_map(
        $this-&gt;getFieldValue($index, 'field1'),
        $this-&gt;getFieldValue($index, 'field2')
      );
    }
    ...