Add framework for calculating the overall elevation/z range of a QgsP…

…roject
qgis · Nov 28, 2020 · 0c7df50 · 0c7df50
1 parent 51ae398
commit 0c7df50
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diff --git a/python/core/auto_generated/pointcloud/qgspointcloudlayerelevationproperties.sip.in b/python/core/auto_generated/pointcloud/qgspointcloudlayerelevationproperties.sip.in
@@ -36,6 +36,7 @@ Constructor for QgsPointCloudLayerElevationProperties, with the specified ``pare
 
     virtual bool isVisibleInZRange( const QgsDoubleRange &range ) const;
 
+    virtual QgsDoubleRange calculateZRange( QgsMapLayer *layer ) const;
 
 };
 

diff --git a/python/core/auto_generated/qgselevationutils.sip.in b/python/core/auto_generated/qgselevationutils.sip.in
@@ -0,0 +1,42 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgselevationutils.h                                         *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+class QgsElevationUtils
+{
+%Docstring
+Contains utility methods for working with elevation from layers and projects.
+
+.. versionadded:: 3.18
+%End
+
+%TypeHeaderCode
+#include "qgselevationutils.h"
+%End
+  public:
+
+    static QgsDoubleRange calculateZRangeForProject( QgsProject *project );
+%Docstring
+Calculates the elevation range for a ``project``.
+
+This method considers the elevation (or z) range available from layers contained within the project and
+returns the maximal combined elevation range of these layers.
+%End
+
+};
+
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgselevationutils.h                                         *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
diff --git a/python/core/auto_generated/qgsmaplayerelevationproperties.sip.in b/python/core/auto_generated/qgsmaplayerelevationproperties.sip.in
@@ -77,6 +77,14 @@ Returns ``True`` if the layer should be visible and rendered for the specified z
     virtual QgsMapLayerElevationProperties::Flags flags() const;
 %Docstring
 Returns flags associated to the elevation properties.
+%End
+
+    virtual QgsDoubleRange calculateZRange( QgsMapLayer *layer ) const;
+%Docstring
+Attempts to calculate the overall elevation or z range for the specified ``layer``, using
+the settings defined by this elevation properties object.
+
+May return an infinite range if the extent could not be calculated.
 %End
 
   signals:

diff --git a/python/core/core_auto.sip b/python/core/core_auto.sip
@@ -54,6 +54,7 @@
 %Include auto_generated/qgsdistancearea.sip
 %Include auto_generated/qgseditformconfig.sip
 %Include auto_generated/qgseditorwidgetsetup.sip
+%Include auto_generated/qgselevationutils.sip
 %Include auto_generated/qgsellipsoidutils.sip
 %Include auto_generated/qgserror.sip
 %Include auto_generated/qgsexpressioncontext.sip

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
@@ -279,6 +279,7 @@ set(QGIS_CORE_SRCS
   qgsdiagramrenderer.cpp
   qgsdistancearea.cpp
   qgseditformconfig.cpp
+  qgselevationutils.cpp
   qgsellipsoidutils.cpp
   qgserror.cpp
   qgseventtracing.cpp
@@ -865,6 +866,7 @@ set(QGIS_CORE_HDRS
   qgsdistancearea.h
   qgseditformconfig.h
   qgseditorwidgetsetup.h
+  qgselevationutils.h
   qgsellipsoidutils.h
   qgserror.h
   qgseventtracing.h

diff --git a/src/core/pointcloud/qgspointcloudlayerelevationproperties.cpp b/src/core/pointcloud/qgspointcloudlayerelevationproperties.cpp
@@ -43,3 +43,9 @@ bool QgsPointCloudLayerElevationProperties::isVisibleInZRange( const QgsDoubleRa
   // TODO -- test actual point cloud z range
   return true;
 }
+
+QgsDoubleRange QgsPointCloudLayerElevationProperties::calculateZRange( QgsMapLayer * ) const
+{
+  // TODO - retrieve range from point cloud data provider
+  return QgsDoubleRange();
+}
diff --git a/src/core/pointcloud/qgspointcloudlayerelevationproperties.h b/src/core/pointcloud/qgspointcloudlayerelevationproperties.h
@@ -46,7 +46,7 @@ class CORE_EXPORT QgsPointCloudLayerElevationProperties : public QgsMapLayerElev
     QDomElement writeXml( QDomElement &element, QDomDocument &doc, const QgsReadWriteContext &context ) override;
     bool readXml( const QDomElement &element, const QgsReadWriteContext &context ) override;
     bool isVisibleInZRange( const QgsDoubleRange &range ) const override;
-
+    QgsDoubleRange calculateZRange( QgsMapLayer *layer ) const override;
 };
 
 #endif // QGSPOINTCLOUDLAYERELEVATIONPROPERTIES_H
diff --git a/src/core/qgselevationutils.cpp b/src/core/qgselevationutils.cpp
@@ -0,0 +1,56 @@
+/***************************************************************************
+  qgselevationutils.cpp
+  ------------------
+  Date                 : November 2020
+  Copyright            : (C) 2020 by Nyall Dawson
+  Email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgselevationutils.h"
+#include "qgsproject.h"
+#include "qgsmaplayerelevationproperties.h"
+
+
+QgsDoubleRange QgsElevationUtils::calculateZRangeForProject( QgsProject *project )
+{
+  const QMap<QString, QgsMapLayer *> &mapLayers = project->mapLayers();
+  QgsMapLayer *currentLayer = nullptr;
+
+  double min = std::numeric_limits<double>::quiet_NaN();
+  double max = std::numeric_limits<double>::quiet_NaN();
+
+  for ( QMap<QString, QgsMapLayer *>::const_iterator it = mapLayers.constBegin(); it != mapLayers.constEnd(); ++it )
+  {
+    currentLayer = it.value();
+
+    if ( !currentLayer->elevationProperties() || !currentLayer->elevationProperties()->hasElevation() )
+      continue;
+
+    const QgsDoubleRange layerRange = currentLayer->elevationProperties()->calculateZRange( currentLayer );
+    if ( layerRange.isInfinite() )
+      continue;
+
+    if ( layerRange.lower() > std::numeric_limits< double >::lowest() )
+    {
+      if ( std::isnan( min ) || layerRange.lower() < min )
+        min = layerRange.lower();
+    }
+
+    if ( layerRange.upper() < std::numeric_limits< double >::max() )
+    {
+      if ( std::isnan( max ) || layerRange.upper() > max )
+        max = layerRange.upper();
+    }
+  }
+
+  return QgsDoubleRange( std::isnan( min ) ? std::numeric_limits< double >::lowest() : min,
+                         std::isnan( max ) ? std::numeric_limits< double >::max() : max );
+}
+
diff --git a/src/core/qgselevationutils.h b/src/core/qgselevationutils.h
@@ -0,0 +1,46 @@
+/***************************************************************************
+  qgselevationutils.h
+  ------------------
+  Date                 : November 2020
+  Copyright            : (C) 2020 by Nyall Dawson
+  Email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSELEVATIONUTILS_H
+#define QGSELEVATIONUTILS_H
+
+#include "qgis_core.h"
+#include "qgsrange.h"
+
+class QgsProject;
+
+/**
+ * \ingroup core
+ * \class QgsElevationUtils
+ * \brief Contains utility methods for working with elevation from layers and projects.
+ *
+ * \since QGIS 3.18
+ */
+class CORE_EXPORT QgsElevationUtils
+{
+  public:
+
+    /**
+     * Calculates the elevation range for a \a project.
+     *
+     * This method considers the elevation (or z) range available from layers contained within the project and
+     * returns the maximal combined elevation range of these layers.
+     */
+    static QgsDoubleRange calculateZRangeForProject( QgsProject *project );
+
+};
+
+
+#endif // QGSELEVATIONUTILS_H
diff --git a/src/core/qgsmaplayerelevationproperties.cpp b/src/core/qgsmaplayerelevationproperties.cpp
@@ -31,3 +31,8 @@ bool QgsMapLayerElevationProperties::isVisibleInZRange( const QgsDoubleRange & )
 {
   return true;
 }
+
+QgsDoubleRange QgsMapLayerElevationProperties::calculateZRange( QgsMapLayer * ) const
+{
+  return QgsDoubleRange();
+}
diff --git a/src/core/qgsmaplayerelevationproperties.h b/src/core/qgsmaplayerelevationproperties.h
@@ -103,6 +103,14 @@ class CORE_EXPORT QgsMapLayerElevationProperties : public QObject
      */
     virtual QgsMapLayerElevationProperties::Flags flags() const { return QgsMapLayerElevationProperties::Flags(); }
 
+    /**
+     * Attempts to calculate the overall elevation or z range for the specified \a layer, using
+     * the settings defined by this elevation properties object.
+     *
+     * May return an infinite range if the extent could not be calculated.
+     */
+    virtual QgsDoubleRange calculateZRange( QgsMapLayer *layer ) const;
+
   signals:
 
     /**