From ec2907359b1563323274130e22edc0e69248a30e Mon Sep 17 00:00:00 2001
From: Josafat-Mattias Burmeister <josafat-mattias.burm@hpi.de>
Date: Sat, 1 Mar 2025 20:44:13 +0100
Subject: [PATCH] fix: DTM generation when some raster cells are empty

---
 src/pcdPointTreeseg2txt.cpp |  2 +-
 src/pcdPointXYZRGB2txt.cpp  |  1 +
 src/treeseg.cpp             | 25 ++++++++++++++-----------
 src/txtPointTreeseg2pcd.cpp |  1 +
 4 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/src/pcdPointTreeseg2txt.cpp b/src/pcdPointTreeseg2txt.cpp
index b189e55..8f979cd 100644
--- a/src/pcdPointTreeseg2txt.cpp
+++ b/src/pcdPointTreeseg2txt.cpp
@@ -1,5 +1,5 @@
 #include "treeseg.h"
-
+#include <boost/algorithm/string.hpp>
 #include <pcl/io/pcd_io.h>
 
 int main (int argc, char **argv)
diff --git a/src/pcdPointXYZRGB2txt.cpp b/src/pcdPointXYZRGB2txt.cpp
index 9fd1520..f99458f 100644
--- a/src/pcdPointXYZRGB2txt.cpp
+++ b/src/pcdPointXYZRGB2txt.cpp
@@ -1,4 +1,5 @@
 #include <pcl/io/pcd_io.h>
+#include <boost/algorithm/string.hpp>
 
 int main (int argc, char **argv)
 {
diff --git a/src/treeseg.cpp b/src/treeseg.cpp
index a7a0fd3..e666d3e 100644
--- a/src/treeseg.cpp
+++ b/src/treeseg.cpp
@@ -39,6 +39,7 @@
 #include <pcl/segmentation/region_growing.h>
 #include <pcl/segmentation/sac_segmentation.h>
 #include <pcl/octree/octree.h>
+#include <boost/algorithm/string.hpp>
 
 //File IO
 
@@ -833,17 +834,19 @@ std::vector<std::vector<float>> getDtmAndSlice(const pcl::PointCloud<PointTreese
 		{
 			spatial1DFilter(tmpcloud,"y",y,y+resolution,tile);
 			std::sort(tile->points.begin(),tile->points.end(),sortCloudByZ);
-			int idx = (percentile / 100) * tile->points.size();
-			float ground = tile->points[idx].z;
-			result.push_back(x);
-			result.push_back(y);
-			result.push_back(ground);
-			dem.push_back(result);
-			spatial1DFilter(tile,"z",ground+zmin,ground+zmax,tileslice);
-			*slice += *tileslice;
-			result.clear();
-			tile->clear();
-			tileslice->clear();
+			if (tile->points.size() > 0) {
+				int idx = (percentile / 100) * tile->points.size();
+				float ground = tile->points[idx].z;
+				result.push_back(x);
+				result.push_back(y);
+				result.push_back(ground);
+				dem.push_back(result);
+				spatial1DFilter(tile,"z",ground+zmin,ground+zmax,tileslice);
+				*slice += *tileslice;
+				result.clear();
+				tile->clear();
+				tileslice->clear();
+			}
 		}
 		tmpcloud->clear();
 	}
diff --git a/src/txtPointTreeseg2pcd.cpp b/src/txtPointTreeseg2pcd.cpp
index cf8b2a0..04abfbe 100644
--- a/src/txtPointTreeseg2pcd.cpp
+++ b/src/txtPointTreeseg2pcd.cpp
@@ -1,6 +1,7 @@
 #include "treeseg.h"
 
 #include <pcl/io/pcd_io.h>
+#include <boost/algorithm/string.hpp>
 
 int main (int argc, char **argv)
 {