From 4948045b7afa42b467db3a5865bab5a64d1f4371 Mon Sep 17 00:00:00 2001
From: Valentin Platzgummer <valentin.platzgummer@ymail.com>
Date: Thu, 31 Dec 2020 17:24:27 +0100
Subject: [PATCH] MeasurementArea prepared for new NemoInterface

---
 QGCExternalLibs.pri                           |   5 -
 qgroundcontrol.pro                            |  10 +-
 .../CircularGenerator.cpp                     |  35 +-
 src/MeasurementComplexItem/HashFunctions.cpp  |   1 +
 src/MeasurementComplexItem/HashFunctions.h    |  32 ++
 .../LinearGenerator.cpp                       |  32 +-
 .../MeasurementComplexItem.cc                 |   2 +-
 src/MeasurementComplexItem/NemoInterface.cpp  |   6 +-
 .../geometry/MeasurementArea.cc               | 415 ++++++++----------
 .../geometry/MeasurementArea.h                |  36 +-
 .../geometry/ProgressArray.h                  |  10 +
 .../geometry/TileDiff.h                       |  11 +
 .../geometry/geometry.h                       |   5 +-
 .../nemo_interface/MeasurementTile.cpp        |  52 +++
 .../nemo_interface/MeasurementTile.h          |  39 ++
 .../nemo_interface/SnakeTile.cpp              |  22 -
 .../nemo_interface/SnakeTile.h                |  22 -
 .../nemo_interface/SnakeTiles.h               |   4 +-
 .../qml/MeasurementAreaMapVisual.qml          |  57 ++-
 src/comm/QmlObjectListHelper.cpp              |   1 +
 src/comm/QmlObjectListHelper.h                |  52 +++
 21 files changed, 474 insertions(+), 375 deletions(-)
 create mode 100644 src/MeasurementComplexItem/HashFunctions.cpp
 create mode 100644 src/MeasurementComplexItem/HashFunctions.h
 create mode 100644 src/MeasurementComplexItem/geometry/ProgressArray.h
 create mode 100644 src/MeasurementComplexItem/geometry/TileDiff.h
 create mode 100644 src/MeasurementComplexItem/nemo_interface/MeasurementTile.cpp
 create mode 100644 src/MeasurementComplexItem/nemo_interface/MeasurementTile.h
 delete mode 100644 src/MeasurementComplexItem/nemo_interface/SnakeTile.cpp
 delete mode 100644 src/MeasurementComplexItem/nemo_interface/SnakeTile.h
 create mode 100644 src/comm/QmlObjectListHelper.cpp
 create mode 100644 src/comm/QmlObjectListHelper.h

diff --git a/QGCExternalLibs.pri b/QGCExternalLibs.pri
index 8566d53a3..8e47d9238 100644
--- a/QGCExternalLibs.pri
+++ b/QGCExternalLibs.pri
@@ -226,11 +226,6 @@ contains (DEFINES, DISABLE_AIRMAP) {
     }
 }
 
-# GeograpicLib (TODO: add Windows support!)
-LinuxBuild {
-    LIBS += -L$$PWD/libs/libGeographic -lGeographic # libGeograpic.so.17
-}
-
 # google or-tools (TODO: add Windows support!)
 LinuxBuild {
     OR_TOOLS_PATH = $$PWD/libs/or-tools-src-ubuntu
diff --git a/qgroundcontrol.pro b/qgroundcontrol.pro
index d5fd5f192..3677488dd 100644
--- a/qgroundcontrol.pro
+++ b/qgroundcontrol.pro
@@ -445,7 +445,11 @@ contains (DEFINES, QGC_ENABLE_PAIRING) {
 #
 
 HEADERS += \
+    src/MeasurementComplexItem/geometry/ProgressArray.h \
+    src/MeasurementComplexItem/geometry/TileDiff.h \
     src/MeasurementComplexItem/geometry/geometry.h \
+    src/MeasurementComplexItem/HashFunctions.h \
+    src/MeasurementComplexItem/nemo_interface/MeasurementTile.h \
     src/QmlControls/QmlUnitsConversion.h \
     src/MeasurementComplexItem/geometry/GeoArea.h \
     src/MeasurementComplexItem/geometry/MeasurementArea.h \
@@ -487,7 +491,6 @@ HEADERS += \
     src/MeasurementComplexItem/nemo_interface/QNemoHeartbeat.h \
     src/MeasurementComplexItem/nemo_interface/QNemoProgress.h \
     src/MeasurementComplexItem/nemo_interface/QNemoProgress.h \
-    src/MeasurementComplexItem/nemo_interface/SnakeTile.h \
     src/MeasurementComplexItem/nemo_interface/SnakeTileLocal.h \
     src/MeasurementComplexItem/nemo_interface/SnakeTiles.h \
     src/MeasurementComplexItem/nemo_interface/SnakeTilesLocal.h \
@@ -498,6 +501,7 @@ HEADERS += \
     src/api/QmlComponentInfo.h \
     src/GPS/Drivers/src/base_station.h \
     src/Settings/WimaSettings.h \
+    src/comm/QmlObjectListHelper.h \
     src/comm/ros_bridge/include/RosBridgeClient.h \
     src/comm/ros_bridge/include/com_private.h \
     src/comm/ros_bridge/include/message_traits.h \
@@ -525,6 +529,8 @@ SOURCES += \
     src/MeasurementComplexItem/geometry/MeasurementArea.cc \
     src/MeasurementComplexItem/geometry/SafeArea.cc \
     src/MeasurementComplexItem/geometry/geometry.cpp \
+    src/MeasurementComplexItem/HashFunctions.cpp \
+    src/MeasurementComplexItem/nemo_interface/MeasurementTile.cpp \
     src/Vehicle/VehicleEscStatusFactGroup.cc \
     src/MeasurementComplexItem/AreaData.cc \
     src/api/QGCCorePlugin.cc \
@@ -541,7 +547,7 @@ SOURCES += \
     src/MeasurementComplexItem/geometry/GeoPoint3D.cpp \
     src/MeasurementComplexItem/NemoInterface.cpp \
     src/MeasurementComplexItem/nemo_interface/QNemoProgress.cc \
-    src/MeasurementComplexItem/nemo_interface/SnakeTile.cpp \
+    src/comm/QmlObjectListHelper.cpp \
     src/comm/ros_bridge/include/RosBridgeClient.cpp \
     src/comm/ros_bridge/include/com_private.cpp \
     src/comm/ros_bridge/include/messages/geographic_msgs/geopoint.cpp \
diff --git a/src/MeasurementComplexItem/CircularGenerator.cpp b/src/MeasurementComplexItem/CircularGenerator.cpp
index d8c7ffa15..c31a5e81e 100644
--- a/src/MeasurementComplexItem/CircularGenerator.cpp
+++ b/src/MeasurementComplexItem/CircularGenerator.cpp
@@ -10,7 +10,7 @@
 #include "geometry/MeasurementArea.h"
 #include "geometry/SafeArea.h"
 #include "geometry/clipper/clipper.hpp"
-#include "nemo_interface/SnakeTile.h"
+#include "nemo_interface/MeasurementTile.h"
 
 QGC_LOGGING_CATEGORY(CircularGeneratorLog, "CircularGeneratorLog")
 
@@ -118,31 +118,22 @@ bool CircularGenerator::get(Work &work) {
       auto pPolygon = std::make_shared<geometry::FPolygon>();
       geometry::areaToEnu(origin, geoPolygon, *pPolygon);
 
-      // Progress and tiles.
-      const auto &progress = measurementArea->progress();
+      // Collect tiles with progress == 100 %.
       const auto *tiles = measurementArea->tiles();
       auto pTiles = std::make_shared<std::vector<geometry::FPolygon>>();
-      if (progress.size() == tiles->count()) {
-        for (int i = 0; i < tiles->count(); ++i) {
-          if (progress[i] == 100) {
-            const auto *obj = (*tiles)[int(i)];
-            const auto *tile = qobject_cast<const SnakeTile *>(obj);
-
-            if (tile != nullptr) {
-              geometry::FPolygon tileENU;
-              geometry::areaToEnu(origin, tile->coordinateList(), tileENU);
-              pTiles->push_back(std::move(tileENU));
-            } else {
-              qCDebug(CircularGeneratorLog)
-                  << "get(): progress.size() != tiles->count().";
-              return false;
-            }
+      for (int i = 0; i < tiles->count(); ++i) {
+        const auto tile =
+            qobject_cast<const MeasurementTile *>(tiles->operator[](i));
+        if (tile != nullptr) {
+          if (qFuzzyCompare(tile->progress(), 100)) {
+            geometry::FPolygon tileENU;
+            geometry::areaToEnu(origin, tile->coordinateList(), tileENU);
+            pTiles->push_back(std::move(tileENU));
           }
+        } else {
+          qCDebug(CircularGeneratorLog) << "get(): tile == nullptr.";
+          return false;
         }
-      } else {
-        qCDebug(CircularGeneratorLog)
-            << "get(): progress.size() != tiles->count().";
-        return false;
       }
 
       auto serviceArea = getGeoArea<const SafeArea *>(*this->_d->areaList());
diff --git a/src/MeasurementComplexItem/HashFunctions.cpp b/src/MeasurementComplexItem/HashFunctions.cpp
new file mode 100644
index 000000000..e3f74aaab
--- /dev/null
+++ b/src/MeasurementComplexItem/HashFunctions.cpp
@@ -0,0 +1 @@
+#include "HashFunctions.h"
diff --git a/src/MeasurementComplexItem/HashFunctions.h b/src/MeasurementComplexItem/HashFunctions.h
new file mode 100644
index 000000000..ce8830660
--- /dev/null
+++ b/src/MeasurementComplexItem/HashFunctions.h
@@ -0,0 +1,32 @@
+#ifndef HASHFUNCTIONS_H
+#define HASHFUNCTIONS_H
+
+#include <QGeoCoordinate>
+#include <functional>
+
+#include <QmlObjectListModel.h>
+
+namespace std {
+
+template <> struct hash<QGeoCoordinate> {
+  std::size_t operator()(const QGeoCoordinate &c) {
+    hash<double> h;
+    return h(c.latitude()) ^ h(c.longitude()) ^ h(c.altitude());
+  }
+};
+
+template <template <class> class Container, class EntryType>
+struct hash<Container<EntryType>> {
+  std::size_t operator()(const Container<EntryType> &list) {
+    std::size_t value = 0;
+    hash<EntryType> h;
+    for (const auto it = std::begin(list); it != std::end(list); ++it) {
+      value ^= h(*it);
+    }
+
+    return value;
+  }
+};
+} // namespace std
+
+#endif // HASHFUNCTIONS_H
diff --git a/src/MeasurementComplexItem/LinearGenerator.cpp b/src/MeasurementComplexItem/LinearGenerator.cpp
index fd9eacc8c..b44b44321 100644
--- a/src/MeasurementComplexItem/LinearGenerator.cpp
+++ b/src/MeasurementComplexItem/LinearGenerator.cpp
@@ -9,7 +9,7 @@
 #include "geometry/clipper/clipper.hpp"
 
 #include "RoutingThread.h"
-#include "nemo_interface/SnakeTile.h"
+#include "nemo_interface/MeasurementTile.h"
 
 namespace routing {
 
@@ -100,29 +100,21 @@ bool LinearGenerator::get(Work &generator) {
       geometry::areaToEnu(origin, geoPolygon, *pPolygon);
 
       // Progress and tiles.
-      const auto &progress = measurementArea->progress();
       const auto *tiles = measurementArea->tiles();
       auto pTiles = std::make_shared<std::vector<geometry::FPolygon>>();
-      if (progress.size() == tiles->count()) {
-        for (int i = 0; i < tiles->count(); ++i) {
-          if (progress[i] == 100) {
-            const QObject *obj = (*tiles)[int(i)];
-            const auto *tile = qobject_cast<const SnakeTile *>(obj);
-
-            if (tile != nullptr) {
-              geometry::FPolygon tileENU;
-              geometry::areaToEnu(origin, tile->coordinateList(), tileENU);
-              pTiles->push_back(std::move(tileENU));
-            } else {
-              qCDebug(LinearGeneratorLog) << "get(): tile == nullptr";
-              return false;
-            }
+      for (int i = 0; i < tiles->count(); ++i) {
+        const auto tile =
+            qobject_cast<const MeasurementTile *>(tiles->operator[](i));
+        if (qFuzzyCompare(tile->progress(), 100)) {
+          if (tile != nullptr) {
+            geometry::FPolygon tileENU;
+            geometry::areaToEnu(origin, tile->coordinateList(), tileENU);
+            pTiles->push_back(std::move(tileENU));
+          } else {
+            qCDebug(LinearGeneratorLog) << "get(): tile == nullptr";
+            return false;
           }
         }
-      } else {
-        qCDebug(LinearGeneratorLog)
-            << "get(): progress.size() != tiles->count().";
-        return false;
       }
 
       auto serviceArea = getGeoArea<const SafeArea *>(*this->_d->areaList());
diff --git a/src/MeasurementComplexItem/MeasurementComplexItem.cc b/src/MeasurementComplexItem/MeasurementComplexItem.cc
index 867b7cc39..06bb3babf 100644
--- a/src/MeasurementComplexItem/MeasurementComplexItem.cc
+++ b/src/MeasurementComplexItem/MeasurementComplexItem.cc
@@ -8,7 +8,7 @@
 #include "geometry/SafeArea.h"
 #include "geometry/clipper/clipper.hpp"
 #include "geometry/geometry.h"
-#include "nemo_interface/SnakeTile.h"
+#include "nemo_interface/MeasurementTile.h"
 
 // QGC
 #include "JsonHelper.h"
diff --git a/src/MeasurementComplexItem/NemoInterface.cpp b/src/MeasurementComplexItem/NemoInterface.cpp
index f8ec2909f..4cfd1f104 100644
--- a/src/MeasurementComplexItem/NemoInterface.cpp
+++ b/src/MeasurementComplexItem/NemoInterface.cpp
@@ -17,7 +17,7 @@
 #include "geometry/geometry.h"
 #include "nemo_interface/QNemoHeartbeat.h"
 #include "nemo_interface/QNemoProgress.h"
-#include "nemo_interface/SnakeTile.h"
+#include "nemo_interface/MeasurementTile.h"
 
 #include "ros_bridge/include/messages/geographic_msgs/geopoint.h"
 #include "ros_bridge/include/messages/jsk_recognition_msgs/polygon_array.h"
@@ -158,7 +158,7 @@ void NemoInterface::Impl::setTileData(const TileData &tileData) {
     UniqueLock lk2(this->tilesENUMutex, std::adopt_lock);
 
     const auto *obj = tileData.tiles[0];
-    const auto *tile = qobject_cast<const SnakeTile *>(obj);
+    const auto *tile = qobject_cast<const MeasurementTile *>(obj);
     if (tile != nullptr) {
       if (tile->coordinateList().size() > 0) {
         if (tile->coordinateList().first().isValid()) {
@@ -167,7 +167,7 @@ void NemoInterface::Impl::setTileData(const TileData &tileData) {
           this->tilesENU.polygons().clear();
           for (int i = 0; i < tileData.tiles.count(); ++i) {
             obj = tileData.tiles[i];
-            tile = qobject_cast<const SnakeTile *>(obj);
+            tile = qobject_cast<const MeasurementTile *>(obj);
             if (tile != nullptr) {
               SnakeTileLocal tileENU;
               geometry::areaToEnu(origin, tile->coordinateList(), tileENU.path());
diff --git a/src/MeasurementComplexItem/geometry/MeasurementArea.cc b/src/MeasurementComplexItem/geometry/MeasurementArea.cc
index 7d4169475..763f8b33e 100644
--- a/src/MeasurementComplexItem/geometry/MeasurementArea.cc
+++ b/src/MeasurementComplexItem/geometry/MeasurementArea.cc
@@ -1,18 +1,22 @@
 #include "MeasurementArea.h"
-#include "QtConcurrentRun"
+#include "HashFunctions.h"
 #include "geometry.h"
-#include "nemo_interface/SnakeTile.h"
+#include "nemo_interface/MeasurementTile.h"
+
 #include <ctime>
 
+#include "QtConcurrentRun"
+#include <QJsonArray>
+#include <QQmlEngine>
+
 #include <boost/units/systems/si.hpp>
 
 #include "JsonHelper.h"
 #include "QGCLoggingCategory.h"
+#include "QmlObjectListHelper.h"
 
-#include <QJsonArray>
-
-#ifndef SNAKE_MAX_TILES
-#define SNAKE_MAX_TILES 1000
+#ifndef MAX_TILES
+#define MAX_TILES 1000
 #endif
 
 using namespace geometry;
@@ -26,142 +30,31 @@ bool getTiles(const FPolygon &area, Length tileHeight, Length tileWidth,
 QGC_LOGGING_CATEGORY(MeasurementAreaLog, "MeasurementAreaLog")
 
 namespace {
-const char *tileCenterPointsKey = "TileCenterPoints";
 const char *tileArrayKey = "TileArray";
 } // namespace
 
-TileData::TileData() : tiles(this) {}
-
-TileData::~TileData() { tiles.clearAndDeleteContents(); }
-
-TileData &TileData::operator=(const TileData &other) {
-  this->tiles.clearAndDeleteContents();
-  for (std::size_t i = 0; i < std::size_t(other.tiles.count()); ++i) {
-    const auto *obj = other.tiles[i];
-    const auto *tile = qobject_cast<const SnakeTile *>(obj);
-    if (tile != nullptr) {
-      this->tiles.append(tile->clone(this));
-    } else {
-      qCWarning(MeasurementAreaLog) << "TileData::operator=: nullptr";
-    }
-  }
-  this->tileCenterPoints = other.tileCenterPoints;
-  return *this;
-}
-
-bool TileData::operator==(const TileData &other) const {
-  if (this->tileCenterPoints == other.tileCenterPoints &&
-      this->tiles.count() == other.tiles.count()) {
-    for (int i = 0; i < other.tiles.count(); ++i) {
-      if (this->tiles[i] != other.tiles[i]) {
-        return false;
-      }
-    }
-    return true;
-  } else {
-    return false;
-  }
-}
+TileData::TileData() {}
+TileData::~TileData() {}
 
+TileData &TileData::operator=(const TileData &other) { return *this; }
+bool TileData::operator==(const TileData &other) const { return false; }
 bool TileData::operator!=(const TileData &other) const {
-  return !this->operator==(other);
-}
-
-void TileData::saveToJson(QJsonObject &json) {
-  // save center points
-  QJsonValue jsonCenterPoints;
-  JsonHelper::saveGeoCoordinateArray(tileCenterPoints, false, jsonCenterPoints);
-  json[tileCenterPointsKey] = std::move(jsonCenterPoints);
-
-  // save tiles
-  QJsonArray jsonTiles;
-  for (int i = 0; i < tiles.count(); ++i) {
-    auto tile = tiles.value<SnakeTile *>(i);
-    if (tile != nullptr) {
-      QJsonObject jsonTile;
-      tile->saveToJson(jsonTile);
-      jsonTiles.append(jsonTile);
-    } else {
-      qCritical() << "TileData::saveToJson(): Object other than SnakeTile "
-                     "inside tiles (QmlObjectListModel))";
-      Q_ASSERT(tile != nullptr);
-    }
-  }
-  json[tileArrayKey] = std::move(jsonTiles);
+  return operator==(other);
 }
 
+void TileData::saveToJson(QJsonObject &json) {}
 bool TileData::loadFromJson(const QJsonObject &json, QString &errorString) {
-  clear();
-
-  // load tiles
-  if (json.contains(tileArrayKey) && json[tileArrayKey].isArray()) {
-    QString e;
-    for (const auto &jsonTile : json[tileArrayKey].toArray()) {
-      auto tile = new SnakeTile(this);
-      if (tile->loadFromJson(jsonTile.toObject(), e)) {
-        tiles.append(tile);
-      } else {
-        tile->deleteLater();
-        errorString.append(e);
-        return false;
-      }
-    }
-  } else {
-    errorString.append(tr("Not able to load tiles.\n"));
-    qCWarning(MeasurementAreaLog)
-        << "Not able to load tiles. tileArrayKey missing or wrong type.";
-    if (json.contains(tileArrayKey)) {
-      qCWarning(MeasurementAreaLog)
-          << "tile array type: " << json[tileArrayKey].type();
-    }
-    return false;
-  }
-
-  // load center points
-  if (json.contains(tileCenterPointsKey) &&
-      json[tileCenterPointsKey].isArray()) {
-    QString e;
-    if (!JsonHelper::loadGeoCoordinateArray(json[tileCenterPointsKey], false,
-                                            tileCenterPoints, e)) {
-      errorString.append(e);
-      errorString.append("\n");
-      return false;
-    }
-
-  } else {
-    errorString.append(tr("Not able to load center points.\n"));
-    qCWarning(MeasurementAreaLog)
-        << "Not able to load center points. tileCenterPointsKey missing or "
-           "wrong type.";
-    if (json.contains(tileCenterPointsKey)) {
-      qCWarning(MeasurementAreaLog)
-          << "center points type: " << json[tileCenterPointsKey].type();
-    }
-    return false;
-  }
-
-  return true;
-}
-
-void TileData::clear() {
-  this->tiles.clearAndDeleteContents();
-  this->tileCenterPoints.clear();
+  return false;
 }
 
-size_t TileData::size() const {
-  if (tiles.count() == tileCenterPoints.size()) {
-    return tiles.count();
-  } else {
-    return 0;
-  }
-}
+void TileData::clear() {}
+std::size_t TileData::size() const { return 0; }
 
 const char *MeasurementArea::settingsGroup = "MeasurementArea";
 const char *tileHeightKey = "TileHeight";
 const char *tileWidthName = "TileWidth";
 const char *minTileAreaKey = "MinTileAreaPercent";
 const char *showTilesKey = "ShowTiles";
-const char *progressKey = "Progress";
 const char *tileKey = "Tiles";
 const char *MeasurementArea::nameString = "Measurement Area";
 
@@ -179,7 +72,8 @@ MeasurementArea::MeasurementArea(QObject *parent)
                                        this /* QObject parent */)),
       _showTiles(SettingsFact(settingsGroup, _metaDataMap[showTilesKey],
                               this /* QObject parent */)),
-      _holdProgress(false), _state(STATE::IDLE) {
+      _tiles(new QmlObjectListModel()), _holdProgress(false),
+      _state(STATE::IDLE) {
   init();
 }
 
@@ -197,7 +91,8 @@ MeasurementArea::MeasurementArea(const MeasurementArea &other, QObject *parent)
                                        this /* QObject parent */)),
       _showTiles(SettingsFact(settingsGroup, _metaDataMap[showTilesKey],
                               this /* QObject parent */)),
-      _holdProgress(false), _state(STATE::IDLE) {
+      _tiles(new QmlObjectListModel()), _holdProgress(false),
+      _state(STATE::IDLE) {
   init();
   disableUpdate();
 
@@ -207,8 +102,12 @@ MeasurementArea::MeasurementArea(const MeasurementArea &other, QObject *parent)
   _showTiles = other._showTiles;
 
   if (other.ready()) {
-    _progress = other._progress;
-    _tileData = other._tileData;
+    for (int i = 0; i < other._tiles->count(); ++i) {
+      _tiles->append(
+          qobject_cast<const MeasurementTile *>(other._tiles->operator[](i))
+              ->clone(_tiles.get()));
+    }
+    _tileMap = other._tileMap;
     enableUpdate();
   } else {
     enableUpdate();
@@ -226,8 +125,13 @@ MeasurementArea &MeasurementArea::operator=(const MeasurementArea &other) {
   _showTiles = other._showTiles;
 
   if (other.ready()) {
-    _progress = other._progress;
-    _tileData = other._tileData;
+    _tiles->clearAndDeleteContents();
+    for (int i = 0; i < other._tiles->count(); ++i) {
+      _tiles->append(
+          qobject_cast<const MeasurementTile *>(other._tiles->operator[](i))
+              ->clone(_tiles.get()));
+    }
+    _tileMap = other._tileMap;
     enableUpdate();
   } else {
     enableUpdate();
@@ -236,7 +140,7 @@ MeasurementArea &MeasurementArea::operator=(const MeasurementArea &other) {
   return *this;
 }
 
-MeasurementArea::~MeasurementArea() {}
+MeasurementArea::~MeasurementArea() { _tiles->clearAndDeleteContents(); }
 
 QString MeasurementArea::mapVisualQML() const {
   return QStringLiteral("MeasurementAreaMapVisual.qml");
@@ -259,32 +163,21 @@ Fact *MeasurementArea::minTileArea() { return &_minTileAreaPercent; }
 
 Fact *MeasurementArea::showTiles() { return &_showTiles; }
 
-QmlObjectListModel *MeasurementArea::tiles() { return &this->_tileData.tiles; }
-
-const QVector<int> &MeasurementArea::progress() const {
-  return this->_progress;
-}
-
-QVector<int> MeasurementArea::progressQml() const { return this->_progress; }
+QmlObjectListModel *MeasurementArea::tiles() { return _tiles.get(); }
 
 const QmlObjectListModel *MeasurementArea::tiles() const {
-  return &this->_tileData.tiles;
+  return _tiles.get();
 }
 
-const QVariantList &MeasurementArea::tileCenterPoints() const {
-  return this->_tileData.tileCenterPoints;
-}
-
-const TileData &MeasurementArea::tileData() const { return this->_tileData; }
-
-int MeasurementArea::maxTiles() const { return SNAKE_MAX_TILES; }
+int MeasurementArea::maxTiles() const { return MAX_TILES; }
 
 bool MeasurementArea::ready() const { return this->_state == STATE::IDLE; }
 
 bool MeasurementArea::measurementCompleted() const {
   if (ready()) {
-    for (const auto &p : _progress) {
-      if (p != 100) {
+    for (int i = 0; i < _tiles->count(); ++i) {
+      const auto tile = qobject_cast<const MeasurementTile *>(_tiles->get(i));
+      if (!qFuzzyCompare(tile->progress(), 100)) {
         return false;
       }
     }
@@ -303,17 +196,15 @@ bool MeasurementArea::saveToJson(QJsonObject &json) {
       json[showTilesKey] = _showTiles.rawValue().toBool();
       json[areaTypeKey] = nameString;
 
-      // save progess
-      QJsonArray jsonProgess;
-      for (const auto &p : _progress) {
-        jsonProgess.append(p);
-      }
-      json[progressKey] = std::move(jsonProgess);
-
       // save tiles
-      QJsonObject jsonTiles;
-      _tileData.saveToJson(jsonTiles);
-      json[tileKey] = std::move(jsonTiles);
+      QJsonArray jsonTileArray;
+      for (int i = 0; i < _tiles->count(); ++i) {
+        auto tile = qobject_cast<MeasurementTile *>(_tiles->get(i));
+        QJsonObject jsonTile;
+        tile->saveToJson(jsonTile);
+        jsonTileArray.append(jsonTile);
+      }
+      json[tileArrayKey] = std::move(jsonTileArray);
 
       return true;
     } else {
@@ -359,52 +250,39 @@ bool MeasurementArea::loadFromJson(const QJsonObject &json,
       _showTiles.setRawValue(json[showTilesKey].toBool());
     }
 
-    // load tiles and progress
+    // load tiles
     bool tileError = false;
-    if (json.contains(tileKey) && json[tileKey].isObject()) {
+    if (json.contains(tileArrayKey) && json[tileArrayKey].isArray()) {
+
       QString e;
-      if (!_tileData.loadFromJson(json[tileKey].toObject(), e)) {
-        qCWarning(MeasurementAreaLog) << "TileData::loadFromJson(): " << e;
-        tileError = true;
-      } else {
-        progressChanged();
-      }
-    } else {
-      tileError = true;
-    }
+      _tiles->clearAndDeleteContents();
+
+      for (auto &&jsonTile : json[tileArrayKey].toArray()) {
 
-    bool progressError = false;
-    QVector<int> prog;
-    if (json.contains(progressKey) && json[progressKey].isArray()) {
-      for (const auto &p : json[progressKey].toArray()) {
-        if (p.isDouble()) {
-          prog.append(p.toDouble());
+        auto tile = new MeasurementTile(this);
+
+        if (tile->loadFromJson(jsonTile.toObject(), e)) {
+          _tiles->append(tile);
         } else {
-          progressError = true;
+          tile->deleteLater();
+          qCWarning(MeasurementAreaLog) << e;
+          tileError = true;
           break;
         }
       }
-
-      // check if entries are in range
-      if (!progressError) {
-        for (const auto &p : prog) {
-          if (p < 0 || p > 100) {
-            progressError = true;
-            break;
-          }
-        }
-      }
     } else {
-      progressError = true;
-    }
-    if (!progressError) {
-      _progress.swap(prog);
-      emit progressChanged();
+      qCWarning(MeasurementAreaLog)
+          << "Not able to load tiles. tileArrayKey missing or wrong type.";
+      if (json.contains(tileArrayKey)) {
+        qCWarning(MeasurementAreaLog)
+            << "tile array type: " << json[tileArrayKey].type();
+      }
+      tileError = true;
     }
 
     // do update if error occurred.
     enableUpdate();
-    if (progressError || tileError) {
+    if (tileError) {
       doUpdate();
     }
 
@@ -426,28 +304,44 @@ bool MeasurementArea::isCorrect() {
   return false;
 }
 
-bool MeasurementArea::setProgress(const QVector<int> &p) {
-  if (ready()) {
-    if (!_holdProgress && p.size() == this->tiles()->count() &&
-        this->_progress != p) {
-      this->_progress = p;
+void MeasurementArea::updateProgress(const ProgressArray &array) {
+  if (ready() && !_holdProgress && array.size() > 0) {
+    bool anyChanges = false;
+    for (const auto &pair : array) {
+      const auto &id = pair.first;
+      const auto &progress = pair.second;
+      auto it = _tileMap.find(id);
+      if (it != _tileMap.end()) {
+        if (!qFuzzyCompare(progress, it->second->progress())) {
+          it->second->setProgress(progress);
+          anyChanges = true;
+        }
+      }
+    }
+
+    if (anyChanges) {
       emit progressChanged();
-      emit progressAccepted();
-      return true;
     }
   }
-  emit progressNotAccepted();
-  return false;
 }
 
 void MeasurementArea::randomProgress() {
   if (ready()) {
+
     std::srand(std::time(nullptr));
-    for (auto &p : _progress) {
+
+    for (int i = 0; i < _tiles->count(); ++i) {
+
+      auto tile = _tiles->value<MeasurementTile *>(i);
+      Q_ASSERT(tile != nullptr);
+
+      auto p = tile->progress();
       p += std::rand() % 125;
       if (p > 100) {
         p = 100;
       }
+
+      tile->setProgress(p);
     }
 
     emit progressChanged();
@@ -456,13 +350,25 @@ void MeasurementArea::randomProgress() {
 
 void MeasurementArea::resetProgress() {
   if (ready()) {
-    for (auto &p : _progress) {
-      p = 0;
+    bool anyChanges = false;
+
+    for (int i = 0; i < _tiles->count(); ++i) {
+
+      auto tile = _tiles->value<MeasurementTile *>(i);
+      Q_ASSERT(tile != nullptr);
+
+      if (!qFuzzyCompare(tile->progress(), 0)) {
+        tile->setProgress(0);
+        anyChanges = true;
+      }
     }
 
-    emit progressChanged();
+    if (anyChanges) {
+      emit progressChanged();
+    }
   }
 }
+
 //!
 //! \brief MeasurementArea::doUpdate
 //! \pre MeasurementArea::deferUpdate must be called first, don't call
@@ -480,7 +386,7 @@ void MeasurementArea::doUpdate() {
     const auto totalArea = this->area() * si::meter * si::meter;
     const auto estNumTiles = totalArea / tileArea;
     // Check some conditions.
-    if (long(std::ceil(estNumTiles.value())) <= SNAKE_MAX_TILES &&
+    if (long(std::ceil(estNumTiles.value())) <= MAX_TILES &&
         this->GeoArea::isCorrect()) {
       setState(STATE::UPDATEING);
 
@@ -491,10 +397,11 @@ void MeasurementArea::doUpdate() {
       const auto minArea =
           this->_minTileAreaPercent.rawValue().toDouble() / 100 * tileArea;
       auto *th = this->thread();
+
       auto future = QtConcurrent::run([polygon, th, height, width, minArea] {
         auto start = std::chrono::high_resolution_clock::now();
 
-        DataPtr pData(new TileData());
+        TilePtr pData(new QmlObjectListModel());
         // Convert to ENU system.
         QGeoCoordinate origin = polygon.first();
         FPolygon polygonENU;
@@ -505,19 +412,17 @@ void MeasurementArea::doUpdate() {
         if (getTiles(polygonENU, height, width, minArea, tilesENU, bbox)) {
           // Convert to geo system.
           for (const auto &t : tilesENU) {
-            auto geoTile = new SnakeTile(pData.get());
+            auto geoTile = new MeasurementTile(pData.get());
+            std::size_t hashValue = 0;
+            std::hash<QGeoCoordinate> hashFun;
             for (const auto &v : t.outer()) {
               QGeoCoordinate geoVertex;
               fromENU(origin, v, geoVertex);
               geoTile->push_back(geoVertex);
+              hashValue ^= hashFun(geoVertex);
             }
-            pData->tiles.append(geoTile);
-            // Calculate center.
-            geometry::FPoint center;
-            geometry::polygonCenter(t, center);
-            QGeoCoordinate geoCenter;
-            fromENU(origin, center, geoCenter);
-            pData->tileCenterPoints.append(QVariant::fromValue(geoCenter));
+            geoTile->setId(long(hashValue));
+            pData->append(geoTile);
           }
         }
         pData->moveToThread(th);
@@ -547,10 +452,10 @@ void MeasurementArea::deferUpdate() {
   if (this->_state == STATE::IDLE || this->_state == STATE::DEFERED) {
     qCDebug(MeasurementAreaLog) << "defereUpdate(): defer update.";
     if (this->_state == STATE::IDLE) {
-      this->_progress.clear();
-      this->_tileData.clear();
-      emit this->progressChanged();
-      emit this->tilesChanged();
+      this->_tileMap.clear();
+      this->_tiles->clearAndDeleteContents();
+      emit tilesChanged();
+      emit progressChanged();
     }
     this->setState(STATE::DEFERED);
     this->_timer.start(100);
@@ -566,11 +471,49 @@ void MeasurementArea::storeTiles() {
   if (this->_state == STATE::UPDATEING) {
     qCDebug(MeasurementAreaLog) << "storeTiles(): update.";
 
-    this->_tileData = *this->_watcher.result();
+    _tiles->clearAndDeleteContents();
+    this->_tiles = this->_watcher.result();
+    this->_watcher.result().reset();
+    QQmlEngine::setObjectOwnership(this->_tiles.get(),
+                                   QQmlEngine::CppOwnership);
+
+    // update tileMap
+    this->_tileMap.clear();
+    for (int i = 0; i < _tiles->count(); ++i) {
+
+      auto tile = qobject_cast<MeasurementTile *>(_tiles->get(i));
+      auto it = _tileMap.find(tile->id());
+
+      // find unique id
+      if (it != _tileMap.end()) {
+        long newId = tile->id() + 1;
+        constexpr long counterMax = 1e6;
+        unsigned long counter = 0;
+        for (; counter <= counterMax; ++counter) {
+          it = _tileMap.find(newId);
+          if (it == _tileMap.end()) {
+            break;
+          } else {
+            ++newId;
+          }
+        }
+
+        if (counter != counterMax) {
+          tile->setId(newId);
+          tile->setProgress(0.0);
+        } else {
+          qCritical()
+              << "MeasurementArea::storeTiles(): not able to find unique id!";
+          continue;
+        }
+      }
+
+      _tileMap.insert(std::make_pair(tile->id(), tile));
+    }
+
     // This is expensive. Drawing tiles is expensive too.
-    this->_progress = QVector<int>(this->_tileData.tiles.count(), 0);
-    this->progressChanged();
     emit this->tilesChanged();
+    emit progressChanged();
     setState(STATE::IDLE);
   } else if (this->_state == STATE::RESTARTING) {
     qCDebug(MeasurementAreaLog) << "storeTiles(): restart.";
@@ -587,7 +530,7 @@ void MeasurementArea::storeTiles() {
 }
 
 void MeasurementArea::disableUpdate() {
-  setState(STATE::IDLE);
+  setState(STATE::STOP);
   this->_timer.stop();
 }
 
@@ -599,6 +542,9 @@ void MeasurementArea::enableUpdate() {
 
 void MeasurementArea::init() {
   this->setObjectName(nameString);
+
+  QQmlEngine::setObjectOwnership(this->_tiles.get(), QQmlEngine::CppOwnership);
+
   connect(&this->_tileHeight, &Fact::rawValueChanged, this,
           &MeasurementArea::deferUpdate);
   connect(&this->_tileWidth, &Fact::rawValueChanged, this,
@@ -632,6 +578,25 @@ void MeasurementArea::setHoldProgress(bool holdProgress) {
   }
 }
 
+void MeasurementArea::updateIds(const QList<TileDiff> &array) {
+  for (const auto &diff : array) {
+
+    auto it = _tileMap.find(diff.oldTile.id());
+
+    if (it != _tileMap.end() &&
+        diff.oldTile.coordinateList() == it->second->coordinateList()) {
+      // Change id and update _tileMap.
+      const auto newId = diff.newTile.id();
+      auto tile = it->second;
+      tile->setId(newId);
+      _tileMap.erase(it);
+      auto ret = _tileMap.insert(std::make_pair(newId, tile));
+      Q_ASSERT(ret.second == true /*insert success?*/);
+      Q_UNUSED(ret);
+    }
+  }
+}
+
 bool getTiles(const FPolygon &area, Length tileHeight, Length tileWidth,
               Area minTileArea, std::vector<FPolygon> &tiles,
               BoundingBox &bbox) {
diff --git a/src/MeasurementComplexItem/geometry/MeasurementArea.h b/src/MeasurementComplexItem/geometry/MeasurementArea.h
index 6b3710e0c..d86b49e17 100644
--- a/src/MeasurementComplexItem/geometry/MeasurementArea.h
+++ b/src/MeasurementComplexItem/geometry/MeasurementArea.h
@@ -6,14 +6,14 @@
 #include <QTimer>
 
 #include "GeoArea.h"
+#include "MeasurementComplexItem/nemo_interface/MeasurementTile.h"
+#include "ProgressArray.h"
+#include "TileDiff.h"
 
 #include "SettingsFact.h"
 
 class TileData : public QObject {
 public:
-  QmlObjectListModel tiles;
-  QVariantList tileCenterPoints;
-
   TileData();
   ~TileData();
 
@@ -26,12 +26,15 @@ public:
 
   void clear();
   std::size_t size() const;
+
+  QmlObjectListModel tiles;
+  QVariantList tileCenterPoints;
 };
 
 class MeasurementArea : public GeoArea {
   Q_OBJECT
   enum class STATE { IDLE, DEFERED, UPDATEING, RESTARTING, STOP };
-  using DataPtr = QSharedPointer<TileData>;
+  using TilePtr = QSharedPointer<QmlObjectListModel>;
 
 public:
   MeasurementArea(QObject *parent = nullptr);
@@ -45,7 +48,6 @@ public:
   Q_PROPERTY(Fact *showTiles READ showTiles CONSTANT)
   Q_PROPERTY(QmlObjectListModel *tiles READ tiles NOTIFY tilesChanged)
   Q_PROPERTY(int maxTiles READ maxTiles NOTIFY maxTilesChanged)
-  Q_PROPERTY(QVector<int> progress READ progressQml NOTIFY progressChanged)
   Q_PROPERTY(bool holdProgress READ holdProgress WRITE setHoldProgress NOTIFY
                  holdProgressChanged)
 
@@ -63,11 +65,7 @@ public:
   Fact *minTileArea();
   Fact *showTiles();
   QmlObjectListModel *tiles();
-  const QVector<int> &progress() const;
-  QVector<int> progressQml() const;
   const QmlObjectListModel *tiles() const;
-  const QVariantList &tileCenterPoints() const; // List of QGeoCoordinate
-  const TileData &tileData() const;
   int maxTiles() const;
   bool ready() const;
 
@@ -92,14 +90,13 @@ public:
 signals:
   void tilesChanged();
   void maxTilesChanged();
-  void progressChanged();
-  void progressAccepted();
-  void progressNotAccepted();
   void readyChanged();
   void holdProgressChanged();
+  void progressChanged();
 
 public slots:
-  bool setProgress(const QVector<int> &p);
+  void updateIds(const QList<TileDiff> &array);
+  void updateProgress(const ProgressArray &array);
   Q_INVOKABLE void randomProgress();
   Q_INVOKABLE void resetProgress();
 
@@ -123,12 +120,11 @@ private:
   SettingsFact _minTileAreaPercent; // 0..100
   SettingsFact _showTiles;
 
-  QVector<int> _progress;
-  bool _holdProgress;
   // Tile stuff.
-  // Tile stuff.
-  mutable QTimer _timer;
-  mutable STATE _state;
-  mutable TileData _tileData;
-  mutable QFutureWatcher<DataPtr> _watcher;
+  TilePtr _tiles;
+  std::map<long /*id*/, MeasurementTile *> _tileMap;
+  bool _holdProgress;
+  QTimer _timer;
+  STATE _state;
+  QFutureWatcher<TilePtr> _watcher;
 };
diff --git a/src/MeasurementComplexItem/geometry/ProgressArray.h b/src/MeasurementComplexItem/geometry/ProgressArray.h
new file mode 100644
index 000000000..ba644ca12
--- /dev/null
+++ b/src/MeasurementComplexItem/geometry/ProgressArray.h
@@ -0,0 +1,10 @@
+#ifndef PROGRESSARRAY_H
+#define PROGRESSARRAY_H
+
+#include <QVector>
+#include <tuple>
+
+typedef std::pair<long /*id*/, double /*progress*/> TaggedProgress;
+typedef QVector<TaggedProgress> ProgressArray;
+
+#endif // PROGRESSARRAY_H
diff --git a/src/MeasurementComplexItem/geometry/TileDiff.h b/src/MeasurementComplexItem/geometry/TileDiff.h
new file mode 100644
index 000000000..4296319ba
--- /dev/null
+++ b/src/MeasurementComplexItem/geometry/TileDiff.h
@@ -0,0 +1,11 @@
+#ifndef TILEDIFF_H
+#define TILEDIFF_H
+
+#include "nemo_interface/MeasurementTile.h"
+
+struct TileDiff {
+  MeasurementTile oldTile;
+  MeasurementTile newTile;
+};
+
+#endif // TILEDIFF_H
diff --git a/src/MeasurementComplexItem/geometry/geometry.h b/src/MeasurementComplexItem/geometry/geometry.h
index a1e59182e..b43cc2383 100644
--- a/src/MeasurementComplexItem/geometry/geometry.h
+++ b/src/MeasurementComplexItem/geometry/geometry.h
@@ -105,8 +105,9 @@ struct BoundingBox {
   FPolygon corners;
 };
 
-constexpr int earth_radius = 6371000;                              // meters (m)
-constexpr double epsilon = std::numeric_limits<double>::epsilon(); // meters (m)
+static constexpr int earth_radius = 6371000; // meters (m)
+static constexpr double epsilon =
+    std::numeric_limits<double>::epsilon(); // meters (m)
 
 template <class GeoPoint1, class GeoPoint2>
 void toENU(const GeoPoint1 &origin, const GeoPoint2 &in, FPoint &out) {
diff --git a/src/MeasurementComplexItem/nemo_interface/MeasurementTile.cpp b/src/MeasurementComplexItem/nemo_interface/MeasurementTile.cpp
new file mode 100644
index 000000000..bcdfc1d4f
--- /dev/null
+++ b/src/MeasurementComplexItem/nemo_interface/MeasurementTile.cpp
@@ -0,0 +1,52 @@
+#include "MeasurementTile.h"
+
+MeasurementTile::MeasurementTile(QObject *parent)
+    : GeoArea(parent), _progress(0), _id(0) {
+  init();
+}
+
+MeasurementTile::MeasurementTile(const MeasurementTile &other, QObject *parent)
+    : GeoArea(other, parent), _progress(other._progress), _id(other._id) {
+  init();
+}
+
+MeasurementTile::~MeasurementTile() {}
+
+MeasurementTile &MeasurementTile::operator=(const MeasurementTile &other) {
+  GeoArea::operator=(other);
+  setProgress(other._progress);
+  setId(other._id);
+  return *this;
+}
+
+QString MeasurementTile::mapVisualQML() const { return QStringLiteral(""); }
+
+QString MeasurementTile::editorQML() const { return QStringLiteral(""); }
+
+MeasurementTile *MeasurementTile::clone(QObject *parent) const {
+  return new MeasurementTile(*this, parent);
+}
+
+void MeasurementTile::push_back(const QGeoCoordinate &c) {
+  this->appendVertex(c);
+}
+
+void MeasurementTile::init() { this->setObjectName("Tile"); }
+
+uint64_t MeasurementTile::id() const { return _id; }
+
+void MeasurementTile::setId(const uint64_t &id) {
+  if (_id != id) {
+    _id = id;
+    emit idChanged();
+  }
+}
+
+double MeasurementTile::progress() const { return _progress; }
+
+void MeasurementTile::setProgress(double progress) {
+  if (_progress != progress) {
+    _progress = progress;
+    emit progressChanged();
+  }
+}
diff --git a/src/MeasurementComplexItem/nemo_interface/MeasurementTile.h b/src/MeasurementComplexItem/nemo_interface/MeasurementTile.h
new file mode 100644
index 000000000..a9409c00b
--- /dev/null
+++ b/src/MeasurementComplexItem/nemo_interface/MeasurementTile.h
@@ -0,0 +1,39 @@
+#pragma once
+
+#include "geometry/GeoArea.h"
+
+#include <QGeoCoordinate>
+
+class MeasurementTile : public GeoArea {
+  Q_OBJECT
+public:
+  MeasurementTile(QObject *parent = nullptr);
+  MeasurementTile(const MeasurementTile &other, QObject *parent = nullptr);
+  ~MeasurementTile();
+
+  MeasurementTile &operator=(const MeasurementTile &other);
+
+  Q_PROPERTY(double progress READ progress NOTIFY progressChanged)
+  Q_PROPERTY(long id READ id NOTIFY idChanged)
+
+  virtual QString mapVisualQML() const override;
+  virtual QString editorQML() const override;
+  virtual MeasurementTile *clone(QObject *parent) const;
+
+  void push_back(const QGeoCoordinate &c);
+
+  double progress() const;
+  void setProgress(double progress);
+
+  uint64_t id() const;
+  void setId(const uint64_t &id);
+
+signals:
+  void progressChanged();
+  void idChanged();
+
+private:
+  void init();
+  double _progress;
+  long _id;
+};
diff --git a/src/MeasurementComplexItem/nemo_interface/SnakeTile.cpp b/src/MeasurementComplexItem/nemo_interface/SnakeTile.cpp
deleted file mode 100644
index febd68cfd..000000000
--- a/src/MeasurementComplexItem/nemo_interface/SnakeTile.cpp
+++ /dev/null
@@ -1,22 +0,0 @@
-#include "SnakeTile.h"
-
-SnakeTile::SnakeTile(QObject *parent) : GeoArea(parent) { init(); }
-
-SnakeTile::SnakeTile(const SnakeTile &other, QObject *parent)
-    : GeoArea(other, parent) {
-  init();
-}
-
-SnakeTile::~SnakeTile() {}
-
-QString SnakeTile::mapVisualQML() const { return QStringLiteral(""); }
-
-QString SnakeTile::editorQML() const { return QStringLiteral(""); }
-
-SnakeTile *SnakeTile::clone(QObject *parent) const {
-  return new SnakeTile(*this, parent);
-}
-
-void SnakeTile::push_back(const QGeoCoordinate &c) { this->appendVertex(c); }
-
-void SnakeTile::init() { this->setObjectName("Tile"); }
diff --git a/src/MeasurementComplexItem/nemo_interface/SnakeTile.h b/src/MeasurementComplexItem/nemo_interface/SnakeTile.h
deleted file mode 100644
index 1beee1f93..000000000
--- a/src/MeasurementComplexItem/nemo_interface/SnakeTile.h
+++ /dev/null
@@ -1,22 +0,0 @@
-#pragma once
-
-#include "geometry/GeoArea.h"
-
-#include <QGeoCoordinate>
-
-class SnakeTile : public GeoArea {
-  Q_OBJECT
-public:
-  SnakeTile(QObject *parent = nullptr);
-  SnakeTile(const SnakeTile &other, QObject *parent = nullptr);
-  ~SnakeTile();
-
-  virtual QString mapVisualQML() const override;
-  virtual QString editorQML() const override;
-  virtual SnakeTile *clone(QObject *parent) const;
-
-  void push_back(const QGeoCoordinate &c);
-
-private:
-  void init();
-};
diff --git a/src/MeasurementComplexItem/nemo_interface/SnakeTiles.h b/src/MeasurementComplexItem/nemo_interface/SnakeTiles.h
index e73c46022..2a0ee2d9f 100644
--- a/src/MeasurementComplexItem/nemo_interface/SnakeTiles.h
+++ b/src/MeasurementComplexItem/nemo_interface/SnakeTiles.h
@@ -1,5 +1,5 @@
 #pragma once
-#include "SnakeTile.h"
+#include "MeasurementTile.h"
 #include "Wima/Geometry/GenericPolygonArray.h"
 
-using SnakeTiles =  GenericPolygonArray<SnakeTile, QVector>;
+using SnakeTiles =  GenericPolygonArray<MeasurementTile, QVector>;
diff --git a/src/MeasurementComplexItem/qml/MeasurementAreaMapVisual.qml b/src/MeasurementComplexItem/qml/MeasurementAreaMapVisual.qml
index 23770c553..bc1a1fa5d 100644
--- a/src/MeasurementComplexItem/qml/MeasurementAreaMapVisual.qml
+++ b/src/MeasurementComplexItem/qml/MeasurementAreaMapVisual.qml
@@ -48,7 +48,34 @@ Item {
         interiorOpacity: _root.opacity
     }
 
-    // Add Snake tiles to the map
+    Repeater {
+        id: progressRepeater
+        property bool enable: geoArea.showTiles.value
+        model: enable ? geoArea.tiles : []
+
+        Item {
+            property var _tileComponent
+
+            Component.onCompleted: {
+                _tileComponent = tileComponent.createObject(map)
+
+                _tileComponent.polygon.path = Qt.binding(function () {
+                    return object.path
+                })
+                _tileComponent.polygon.opacity = 0.6
+                _tileComponent.polygon.border.color = "black"
+                _tileComponent.polygon.border.width = 1
+                _tileComponent.polygon.color = Qt.binding(function () {
+                    return getColor(object.progress)
+                })
+            }
+
+            Component.onDestruction: {
+                _tileComponent.destroy()
+            }
+        }
+    }
+
     Component {
         id: tileComponent
 
@@ -86,32 +113,4 @@ Item {
         return "limegreen"
     }
 
-    Repeater {
-        id: progressRepeater
-        property bool enable: geoArea.showTiles.value
-        model: enable ? geoArea.tiles : []
-
-        Item {
-            property var _tileComponent
-            property int _progress: _root.geoArea.progress[index] ? _root.geoArea.progress[index] : 0
-
-            Component.onCompleted: {
-                _tileComponent = tileComponent.createObject(map)
-
-                _tileComponent.polygon.path = Qt.binding(function () {
-                    return object.path
-                })
-                _tileComponent.polygon.opacity = 0.6
-                _tileComponent.polygon.border.color = "black"
-                _tileComponent.polygon.border.width = 1
-                _tileComponent.polygon.color = Qt.binding(function () {
-                    return getColor(_progress)
-                })
-            }
-
-            Component.onDestruction: {
-                _tileComponent.destroy()
-            }
-        }
-    }
 }
diff --git a/src/comm/QmlObjectListHelper.cpp b/src/comm/QmlObjectListHelper.cpp
new file mode 100644
index 000000000..840b1ab96
--- /dev/null
+++ b/src/comm/QmlObjectListHelper.cpp
@@ -0,0 +1 @@
+#include "QmlObjectListHelper.h"
diff --git a/src/comm/QmlObjectListHelper.h b/src/comm/QmlObjectListHelper.h
new file mode 100644
index 000000000..2b945bcaa
--- /dev/null
+++ b/src/comm/QmlObjectListHelper.h
@@ -0,0 +1,52 @@
+#ifndef QMLOBJECTLISTHELPER_H
+#define QMLOBJECTLISTHELPER_H
+
+#include "QmlObjectListModel.h"
+
+#include <type_traits>
+
+template <class PtrType>
+inline bool contains(const QmlObjectListModel &in, const PtrType toFind) {
+
+  static_assert(std::is_pointer<PtrType>::value, "PtrType must be a pointer.");
+
+  typedef typename std::remove_pointer<PtrType>::type Type;
+
+  for (int i = 0; i < in.count(); ++i) {
+    const auto obj = qobject_cast<const Type *>(in[i]);
+    Q_ASSERT(obj != nullptr);
+    Q_ASSERT(toFind != nullptr);
+    if (*obj == *toFind) {
+      return true;
+    }
+  }
+  return false;
+}
+
+template <class PtrType>
+inline bool equals(const QmlObjectListModel &list,
+                   const QmlObjectListModel &otherList) {
+
+  static_assert(std::is_pointer<PtrType>::value, "PtrType must be a pointer.");
+
+  typedef typename std::remove_pointer<PtrType>::type Type;
+
+  if (list.count() == otherList.count()) {
+
+    for (int i = 0; i < list.count(); ++i) {
+      const auto obj = qobject_cast<const Type *>(list[i]);
+      const auto otherObj = qobject_cast<const Type *>(otherList[i]);
+      Q_ASSERT(obj != nullptr);
+      Q_ASSERT(otherObj != nullptr);
+      if (*obj != *otherObj) {
+        return false;
+      }
+    }
+
+    return true;
+  } else {
+    return false;
+  }
+}
+
+#endif // QMLOBJECTLISTHELPER_H
-- 
2.22.0