QGIS API Documentation 3.27.0-Master (a46f227e17)
qgspointcloudstatistics.cpp
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1/***************************************************************************
2 qgspointcloudstatistics.h
3 --------------------
4 begin : May 2022
5 copyright : (C) 2022 by Belgacem Nedjima
6 email : belgacem dot nedjima at gmail dot com
7 ***************************************************************************/
8
9/***************************************************************************
10 * *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
15 * *
16 ***************************************************************************/
17
19
20#include <limits>
21#include <QJsonObject>
22#include <QJsonDocument>
23
25#include "qgsmessagelog.h"
26
27// QgsPointCloudAttributeStatistics
28
30{
31 minimum = std::min( minimum, stats.minimum );
32 maximum = std::max( maximum, stats.maximum );
33
34 double newMean = ( mean * count + stats.mean * stats.count ) / ( count + stats.count );
35 double delta1 = newMean - mean;
36 double variance1 = stDev * stDev + delta1 * delta1 - 2 * count * delta1 * mean;
37 double delta2 = newMean - stats.mean;
38 double variance2 = stats.stDev * stats.stDev + delta2 * delta2 - 2 * stats.count * delta2 * stats.mean;
39 stDev = ( variance1 * count + variance2 * stats.count ) / ( count + stats.count );
40 stDev = std::sqrt( stDev );
41
42 mean = newMean;
43 count += stats.count;
44
45 for ( int key : stats.classCount.keys() )
46 {
47 int c = classCount.value( key, 0 );
48 c += stats.classCount[ key ];
49 classCount[ key ] = c;
50 }
51}
52
53// QgsPointCloudStatistics
54
56{
57
58}
59
60QgsPointCloudStatistics::QgsPointCloudStatistics( int sampledPointsCount, const QMap<QString, QgsPointCloudAttributeStatistics> &stats )
61 : mSampledPointsCount( sampledPointsCount ), mStatisticsMap( stats )
62{
63
64}
65
67{
68 mStatisticsMap.clear();
69}
70
71void QgsPointCloudStatistics::clear( const QVector<QgsPointCloudAttribute> &attributes )
72{
73 for ( QgsPointCloudAttribute attribute : attributes )
74 {
75 mStatisticsMap.remove( attribute.name() );
76 }
77}
78
80{
82 defaultVal.minimum = std::numeric_limits<double>::max();
83 defaultVal.maximum = std::numeric_limits<double>::lowest();
84 defaultVal.count = 0;
85 return mStatisticsMap.value( attribute, defaultVal );
86}
87
88QList<int> QgsPointCloudStatistics::classesOf( const QString &attribute ) const
89{
90 if ( !mStatisticsMap.contains( attribute ) )
91 return QList<int>();
92 QgsPointCloudAttributeStatistics s = mStatisticsMap[ attribute ];
93 return s.classCount.keys();
94}
95
96QMap<int, int> QgsPointCloudStatistics::availableClasses( const QString &attribute ) const
97{
98 if ( !mStatisticsMap.contains( attribute ) )
99 return QMap<int, int>();
100 return mStatisticsMap[ attribute ].classCount;
101}
102
103double QgsPointCloudStatistics::minimum( const QString &attribute ) const
104{
105 if ( !mStatisticsMap.contains( attribute ) )
106 return std::numeric_limits<double>::quiet_NaN();
107 return mStatisticsMap[ attribute ].minimum;
108}
109
110double QgsPointCloudStatistics::maximum( const QString &attribute ) const
111{
112 if ( !mStatisticsMap.contains( attribute ) )
113 return std::numeric_limits<double>::quiet_NaN();
114 return mStatisticsMap[ attribute ].maximum;
115}
116
117double QgsPointCloudStatistics::mean( const QString &attribute ) const
118{
119 if ( !mStatisticsMap.contains( attribute ) )
120 return std::numeric_limits<double>::quiet_NaN();
121 return mStatisticsMap[ attribute ].mean;
122}
123
124double QgsPointCloudStatistics::stDev( const QString &attribute ) const
125{
126 if ( !mStatisticsMap.contains( attribute ) )
127 return std::numeric_limits<double>::quiet_NaN();
128 return mStatisticsMap[ attribute ].stDev;
129}
130
131
133{
134 for ( const QString &attribute : stats.mStatisticsMap.keys() )
135 {
136 QgsPointCloudAttributeStatistics s = stats.mStatisticsMap[ attribute ];
137 if ( mStatisticsMap.contains( attribute ) )
138 {
139 s.cumulateStatistics( mStatisticsMap[ attribute ] );
140 }
141 mStatisticsMap[ attribute ] = s;
142 }
143 mSampledPointsCount += stats.mSampledPointsCount;
144}
145
147{
148 QJsonObject obj;
149 obj.insert( QStringLiteral( "sampled-points" ), QJsonValue::fromVariant( sampledPointsCount() ) );
150 QJsonObject stats;
151 for ( const QString &attr : mStatisticsMap.keys() )
152 {
153 QgsPointCloudAttributeStatistics stat = mStatisticsMap.value( attr );
154 stats.insert( attr, attributeStatisticsToJson( stat ) );
155 }
156 obj.insert( QStringLiteral( "stats" ), stats );
157
158 QJsonDocument statsDoc( obj );
159 return statsDoc.toJson( QJsonDocument::Compact );
160}
161
163{
164 QJsonParseError error;
165 QJsonDocument document = QJsonDocument::fromJson( statsByteArray, &error );
166 if ( error.error != QJsonParseError::NoError )
167 {
168 QgsMessageLog::logMessage( QObject::tr( "Failed to load statistics JSON from COPC file, reason: %1" ).arg( error.errorString() ) );
170 }
171
172 QJsonObject statsJson = document.object();
173
175 stats.mSampledPointsCount = statsJson.value( QStringLiteral( "sampled-points" ) ).toInt();
176 if ( statsJson.contains( QStringLiteral( "stats" ) ) )
177 {
178 QJsonObject statsObj = statsJson.value( QStringLiteral( "stats" ) ).toObject();
179 for ( const QString &attr : statsObj.keys() )
180 {
181 QJsonObject obj = statsObj.value( attr ).toObject();
182 QgsPointCloudAttributeStatistics attrStats = fromAttributeStatisticsJson( obj );
183 attrStats.count = stats.mSampledPointsCount;
184 stats.mStatisticsMap.insert( attr, attrStats );
185 }
186 }
187 return stats;
188}
189
190QJsonObject QgsPointCloudStatistics::attributeStatisticsToJson( const QgsPointCloudAttributeStatistics &stats )
191{
192 QJsonObject obj;
193 obj.insert( QStringLiteral( "minimum" ), stats.minimum );
194 obj.insert( QStringLiteral( "maximum" ), stats.maximum );
195 obj.insert( QStringLiteral( "mean" ), stats.mean );
196 if ( !std::isnan( stats.stDev ) )
197 {
198 obj.insert( QStringLiteral( "standard-deviation" ), stats.stDev );
199 }
200 QJsonObject classCount;
201 for ( const int &c : stats.classCount.keys() )
202 {
203 classCount.insert( QString::number( c ), stats.classCount[c] );
204 }
205 obj.insert( QStringLiteral( "class-count" ), classCount );
206 return obj;
207}
208
209QgsPointCloudAttributeStatistics QgsPointCloudStatistics::fromAttributeStatisticsJson( QJsonObject &statsJson )
210{
212 QVariantMap m = statsJson.toVariantMap();
213 statsObj.minimum = m.value( QStringLiteral( "minimum" ), std::numeric_limits<double>::max() ).toDouble();
214 statsObj.maximum = m.value( QStringLiteral( "maximum" ), std::numeric_limits<double>::lowest() ).toDouble();
215 statsObj.mean = m.value( QStringLiteral( "mean" ), 0 ).toDouble();
216 statsObj.stDev = m.value( QStringLiteral( "standard-deviation" ), std::numeric_limits<double>::quiet_NaN() ).toDouble();
217 QJsonObject classCountJson = statsJson.value( QStringLiteral( "class-count" ) ).toObject();
218 for ( const QString &key : classCountJson.keys() )
219 {
220 statsObj.classCount.insert( key.toInt(), classCountJson.value( key ).toInt() );
221 }
222 return statsObj;
223}
static void logMessage(const QString &message, const QString &tag=QString(), Qgis::MessageLevel level=Qgis::MessageLevel::Warning, bool notifyUser=true)
Adds a message to the log instance (and creates it if necessary).
Attribute for point cloud data pair of name and size in bytes.
Class used to store statistics of a point cloud dataset.
static QgsPointCloudStatistics fromStatisticsJson(QByteArray stats)
Creates a statistics object from the JSON object stats.
double maximum(const QString &attribute) const
Returns the maximum value for the attribute attribute If no matching statistic is available then NaN ...
double stDev(const QString &attribute) const
Returns the standard deviation value for the attribute attribute If no matching statistic is availabl...
void clear()
Clears the statistics of all attributes.
QMap< int, int > availableClasses(const QString &attribute) const
Returns a map containing the count of each class of the attribute attribute If no matching statistic ...
QList< int > classesOf(const QString &attribute) const
Returns a list of existing classes which are present for the specified attribute.
double mean(const QString &attribute) const
Returns the mean value for the attribute attribute If no matching statistic is available then NaN wil...
void combineWith(const QgsPointCloudStatistics &stats)
Merges the current statistics with the statistics from stats.
double minimum(const QString &attribute) const
Returns the minimum value for the attribute attribute If no matching statistic is available then NaN ...
int sampledPointsCount() const
Returns the number of points used to calculate the statistics.
QByteArray toStatisticsJson() const
Converts the current statistics object into JSON object.
QgsPointCloudAttributeStatistics statisticsOf(const QString &attribute) const
Returns the calculated statistics of attribute attribute.
As part of the API refactoring and improvements which landed in the Processing API was substantially reworked from the x version This was done in order to allow much of the underlying Processing framework to be ported into c
Class used to store statistics of one attribute of a point cloud dataset.
void cumulateStatistics(const QgsPointCloudAttributeStatistics &stats)
Updates the current point cloud statistics to hold the cumulation of the current statistics and stats...