Location migration not working I'm trying to convert a d6 location field into a a d8 geolocation field, but when I run it the field does not get updated, and I don't get any messages either. 

All of the other node data has been imported already so I am running the migration with the command: drush migrate-import ttf_location_migration --update

I am including title because without it I get an mySQL error message.

Here's my migration YML file:

id: ttf_location_migration

label: Migrate old location data to geolocation field

source:
  plugin: ttf_location
  key: ttf_migrate

process:
  nid: nid
  title: title
  type: type
  'field_location/bundle': type
  'field_location/deleted':
    plugin: default_value
    default_value: 0
  'field_location/entity_id': nid
  'field_location/revision_id': nid
  'field_location/langcode':
    plugin: default_value
    default_value: 'en'
  'field_location/delta': 
    plugin: default_value
    default_value: 0
  'field_location/field_location_lat': latitude
  'field_location/field_location_lng': longitude


destination:
  plugin: entity:node
  overwrite_properties:
    - 'field_location/bundle'
    - 'field_location/deleted'
    - 'field_location/entity_id'
    - 'field_location/revision_id'
    - 'field_location/langcode'
    - 'field_location/delta' 
    - 'field_location/field_location_lat'
    - 'field_location/field_location_lng'

migration_dependencies: {}

dependencies:
  enforced:
    module:
      - ttf_migrate


and my source plugin:

&lt;?php

namespace Drupal\ttf_migrate\Plugin\migrate\source;

use Drupal\migrate\Plugin\migrate\source\SqlBase;
use Drupal\migrate\Row;

/**
 * Source plugin for location.
 *
 * @MigrateSource(
 *   id = "ttf_location"
 * )
 */
class TtfLocation extends SqlBase {

  /**
   * {@inheritdoc}
   */
  public function query() {


    $query = $this-&gt;select('location', 'l')
      -&gt;fields('l', ['lid', 'latitude', 'longitude']);
    $query-&gt;join('location_instance','li','l.lid = li.lid');
    $query-&gt;fields('li', ['nid']);
    $query-&gt;join('node', 'n', 'li.nid = n.nid');
    $query-&gt;fields('n', ['type', 'title']);

    return $query;
  }

  /**
   * {@inheritdoc}
   */
  public function fields() {
    $fields = [
      'lid' =&gt; $this-&gt;t('Location ID'),
      'latitude' =&gt; $this-&gt;t('Latitude'),
      'longitude' =&gt; $this-&gt;t('longitude'),
      'nid' =&gt; $this-&gt;t('Content ID'),
      'type' =&gt; $this-&gt;t('Type'),
      'title'=&gt;$this-&gt;t('Title')
    ];

    return $fields;
  }

  /**
   * {@inheritdoc}
   */
  public function getIds() {
    return [
      'nid' =&gt; [
        'type' =&gt; 'integer',
        'alias' =&gt; 'nid',
      ],
    ];
  }

}



Any help much appreciated

Thank you
Do not repeat the field name for sub columns: Instead of e.g. field_location/field_location_lat use only field_location/lat, in the process:  section. 

There also is no need to manually set interal keys like entity_id or revision_id: Only set the destination plugin and the field values, and Migrate module will fill all other internal columns for you.

destination:
  plugin: entity:node

process:
  title: title
  type:
    plugin: default_value
    value: NODE_BUNDLE_NAME
  langcode:
    plugin: default_value
    value: 'en'
  field_location/lat: latitude
  field_location/lng: longitude