Merge branch 'main' of gitlab.com:Trygve/contour-creator

documentation/slides.md

@@ -5,16 +5,31 @@ author:
 - Trygve og Esther
 
 ---
-# What are contours
 
-# Output of our program
+# Output of our program:
-pretty pictures
+![Contour map of Ås](kurver_ås.png)
+
+# Marching squares
+![By Nicoguaro; Adroitwhiz - File:Marching_squares_algorithm.svg, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=143418710](ms_wikipedia.svg)
 
 # The logical flow of our program
-flowchart
+```cpp
-
+int main(int argc, const char* argv[])
-# GDAL
+{
-What is it?
+    const char* filepath = argv[1];
+    HeightMap map(filepath); 
+    map.blur(0.8)
+    auto lines = create_lines(&map, 5);
+    write_output_file(cellmaps, "out.geojson", &map);
+}
+```
 
 # Performance
-show the benchmarks
+|                    |       Time         |
+|--------------------|--------------------|
+|  12 threads        |     41s            |
+|   1 thread         |     116s           |
+
+
+# Problems we encountered
+

src/contour_creator.hh

@@ -43,13 +43,10 @@ class Point
         int x;
         int y;
         int mscase;
-        Point * next;
+        bool allocated = false;
-        Point * previous;
         Point(int x, int y, int mscase){
             this -> x = x;
             this -> y = y;
             this -> mscase = mscase;
-            this -> next = nullptr;
-            this -> previous = nullptr;
         };
 };

src/main.cpp

@@ -5,7 +5,6 @@
 #include <gdal/ogr_feature.h>
 #include <gdal/ogr_geometry.h>
 #include <iostream>
-#include <iterator>
 #include <ostream>
 #include <vector>
 #include <cstdint>
@@ -22,28 +21,21 @@ std::vector<Point> produce_cellmap(HeightMap* heightmap, float z)
     for (int i = 0; i<length; i++) {
         int y = i/(heightmap->width-1);
         int x = i%(heightmap->width-1);
-        uint8_t result = (heightmap->get_pixel(x,y)>z) + 
+        uint8_t result = (heightmap->get_pixel(x,y)>z)*8 + 
-        (heightmap->get_pixel(x+1,y)>z)*2 +
+        (heightmap->get_pixel(x+1,y)>z)*4 +
-        (heightmap->get_pixel(x+1,y+1)>z)*4 +
+        (heightmap->get_pixel(x+1,y+1)>z)*2 +
-        (heightmap->get_pixel(x,y+1)>z)*8;
+        (heightmap->get_pixel(x,y+1)>z);
         if (result != 0 and result != 15 ) {
             points.push_back(Point(x, y, result));
-
         };
     }
-    
     return points;
-
-
 }
 
-
+std::vector<std::vector<Point>> create_lines(HeightMap* heightmap, int interval)
-
-std::vector<std::vector<Point>> vector_cellmap(HeightMap* heightmap, int interval)
 {
     int num_contours = (heightmap->max - heightmap->min)/interval;
-    std::vector<std::vector<Point>> vector_contours; // initiating a vector of contours
+    std::vector<std::vector<Point>> vector_contours;
-    omp_set_num_threads(12);
 
     #pragma omp parallel
     {
@@ -52,26 +44,67 @@ std::vector<std::vector<Point>> vector_cellmap(HeightMap* heightmap, int interva
         for (int i = 1; i <= num_contours; i++) 
         {
             auto points = produce_cellmap(heightmap, heightmap->min + interval*i);
-                
+            std::vector<Point> line;
-            for (int j = 0; j < points.size(); j++){ //looping through all the points.
+            int x;
-                Point current = points[j]; // assigning an instance of Point class to a point.
+            int y;
-                //std::cout << points_allocated << " " << points.size() << "\n";
+            int points_allocated = 0;
-                for (int k = 0; k < points.size(); k++){ // looping through all other points.
+            x = points[0].x;
-                    Point candidate = points[k]; 
+            y = points[0].y;
-                    if (candidate.next != nullptr) {
+            points[0].allocated = true;
-                        if (candidate.x +1 == current.x) {
+            line.push_back(points[0]);
-                            current.next = &candidate;
+            for (int j = 0; j < points.size(); j++){
+                for (int k = 0; k < points.size(); k++){
+                    Point* candidate = &points[k];
+                    if (!candidate->allocated) {
+                        if (candidate->x == x +1 && candidate->y == y) {
+                            candidate->allocated = true;
+                            x = candidate->x;
+                            y = candidate->y;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
                         }
-                        else if (candidate.x -1 == current.x) {
+                        else if (candidate->x == x -1 && candidate->y == y) {
-                            current.next = &candidate;
+                            x = candidate->x;
+                            y = candidate->y;
+                            candidate->allocated = true;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
                         }
-                        else if (candidate.y +1 == current.x) {
+                        else if (candidate->x == x && candidate->y == y + 1) {
-                            current.next = &candidate;
+                            x = candidate->x;
+                            y = candidate->y;
+                            candidate->allocated = true;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
                         }
-                        else if (candidate.y -1 == current.x) {
+                        else if (candidate->x == x && candidate->y == y - 1) {
-                            current.next = &candidate;
+                            x = candidate->x;
+                            y = candidate->y;
+                            candidate->allocated = true;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
+                        }
+                    }
+                }
+                if (j > points_allocated)
+                {
+                    vec_private.push_back(line);
+                    line.clear();
+                    //std::cout << points.size() << " ";
+                    for (int k = 0; k < points.size(); k++){
+                        Point* candidate = &points[k];
+                        if (!candidate->allocated)
+                        {
+                            line.push_back(*candidate);
+                            x = candidate->x;
+                            y = candidate->y;
+                            points_allocated++;
+                            break;
                         }
-                        
                     }
                 }
             }
@@ -98,7 +131,7 @@ constexpr std::tuple<double, double, double, double> marching_squares_lookup(int
     switch (mcase) {
         case 1: return {0, 0.5, 0.5, 0};
         case 2: return {1, 0.5, 0.5, 0};
-        case 3: return {0, 0.5, 1, 0};
+        case 3: return {0, 0.5, 1, 0.5};
         case 4: return {0.5, 1, 1, 0.5};
         case 5: return {0, 0, 0, 0}; //FIXME
         case 6: return {0.5, 1, 0.5, 0};
@@ -138,7 +171,7 @@ void write_output_file(std::vector<std::vector<Point>> all_points, const char *f
 
     OGRLayer *poLayer;
 
-    poLayer = poDS->CreateLayer( "contours", /*&(cellmaps[0]).reference_system*/ NULL, wkbLineString, NULL );
+    poLayer = poDS->CreateLayer( "contours", &heightmap->reference_system, wkbLineString, NULL );
     if( poLayer == NULL )
     {
         printf( "Layer creation failed.\n" );
@@ -160,49 +193,35 @@ void write_output_file(std::vector<std::vector<Point>> all_points, const char *f
 
     for (int j = 0; j < all_points.size(); j++)
     {
-            OGRFeature *feature;
+        OGRFeature *feature;
-            OGRLineString *geometry = new OGRLineString();
+        OGRLineString *geometry = new OGRLineString();
-            feature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
+        feature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
-            feature->SetField( "Name", j );
+        feature->SetField( "Name", j );
-
 
         std::vector<Point> points = all_points[j];
 
-        for (int i = 0; i < points.size(); i++) 
+        for (int k = 0; k < points.size(); k++)
         {
-
+            int x_raw = points[k].x;
-            //int x_raw = i%width;
+            int y_raw = points[k].y;
-            //int y_raw = i/height;
-            int x_raw = points[i].x;
-            int y_raw = points[i].y;
             auto [x, y] = local_to_projected(heightmap->geotransform, x_raw, y_raw);
             //auto [x_bl, y_bl, x_tr, y_tr] = marching_squares_lookup(*(cellmap->cells + i) );
-            //std::cout << x << ", " << y << "  ";
-            //geometry->setPoint( geometry->getNumPoints(), x+x_tr*0.25, y+y_tr*0.25 ); 
-            //geometry->setPoint( geometry->getNumPoints(), x+x_bl*0.25, y+y_bl*0.25 ); 
             geometry->setPoint(geometry->getNumPoints(),x ,y );
-
-
-                
-            
         }
 
-                    if ( feature->SetGeometry(geometry) != OGRERR_NONE)
+        if ( feature->SetGeometry(geometry) != OGRERR_NONE)
-            {
+        {
-                printf( "Failed to set geometry.\n" );
+            printf( "Failed to set geometry.\n" );
-                exit( 1 );
+            exit( 1 );
-            }
+        }
-            OGRGeometryFactory::destroyGeometry(geometry);
+        OGRGeometryFactory::destroyGeometry(geometry);
-            if( poLayer->CreateFeature( feature ) != OGRERR_NONE )
+        if( poLayer->CreateFeature( feature ) != OGRERR_NONE )
-            {
+        {
-                printf( "Failed to create feature in shapefile.\n" );
+            printf( "Failed to create feature in shapefile.\n" );
-                exit( 1 );
+            exit( 1 );
-            }
+        }
-            OGRFeature::DestroyFeature( feature );  
+        OGRFeature::DestroyFeature( feature );
-        
-
     }
-
     GDALClose( poDS );
 }
 
@@ -216,8 +235,6 @@ int main(int argc, const char* argv[])
 
     map.blur(0.8);
     
-    auto cellmap = produce_cellmap(&map, 40);
+    auto lines = create_lines(&map, 5);
-    
+    write_output_file(lines, "out.geojson", &map);
-    auto cellmaps = vector_cellmap(&map, 5);
-    write_output_file(cellmaps, "out.geojson", &map);
 }