Fix lookuptable

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "extern/argh"]
+	path = extern/argh
+	url = https://github.com/adishavit/argh.git

CMakeLists.txt

@@ -1,15 +1,22 @@
+cmake_minimum_required(VERSION 3.20)
+
 project(
   contour-creator
   LANGUAGES CXX)    
   
-find_package(GDAL CONFIG REQUIRED)
-
 add_executable(${PROJECT_NAME}
 	src/HeightMap.cpp src/CellMap.cpp src/main.cpp
 )
+
+# Argh is a simple argrument parser
+add_subdirectory(extern/argh)
+target_link_libraries(${PROJECT_NAME} PRIVATE argh)
+
+# Gdal is used for geodata IO
+find_package(GDAL CONFIG REQUIRED)
+target_link_libraries(${PROJECT_NAME} PRIVATE GDAL::GDAL)
+
 find_package(OpenMP)
 if(OpenMP_CXX_FOUND)
     target_link_libraries(${PROJECT_NAME} PUBLIC OpenMP::OpenMP_CXX)
-endif()
+endif()
-
-target_link_libraries(${PROJECT_NAME} GDAL::GDAL)

build&run.sh

@@ -3,4 +3,4 @@ rm -rf build
 mkdir build
 cmake -DCMAKE_BUILD_TYPE=Debug -B build
 cmake --build build --parallel 
-build/contour-creator 'example_files/crop.tif'
+build/contour-creator --interval=1 --blur example_files/crop.tif

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

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

src/main.cpp

@@ -1,4 +1,6 @@
 #include "contour_creator.hh"
+#include <algorithm>
+#include <array>
 #include <gdal/ogr_api.h>
 #include "ogrsf_frmts.h"
 #include <gdal/ogr_core.h>
@@ -6,43 +8,49 @@
 #include <gdal/ogr_geometry.h>
 #include <iostream>
 #include <ostream>
+#include <sys/types.h>
+#include <tuple>
 #include <vector>
 #include <cstdint>
 #include <gdal/gdal.h>
 #include "gdal/gdal_priv.h"
 #include <gdal/gdal_frmts.h>
 #include <omp.h>
+#include "argh.h"
 
 std::vector<Point> produce_cellmap(HeightMap* heightmap, float z)
 {
-    int length = (heightmap->width-1)*(heightmap->height-1);
+    int length = (heightmap->width-1)*(heightmap->height-1); // Defining length of vector
     uint8_t *cells = (uint8_t *) CPLMalloc(sizeof(uint8_t)*length);
-    std::vector<Point> points;
+    std::vector<Point> points; // Initiating a vector of points
     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;
-
-
 }
 
+bool is_in(int value, std::array<int, 8> array)
+{
+    return std::binary_search(array.begin(), array.end(), value);
+}
 
-
+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;
-    omp_set_num_threads(12);
+
+    std::array<int,8> north{4, 5,6,7,8,9,10,11};
+    std::array<int,8> south{1,2,5,6,9,10,13,14};
+    std::array<int,8> east{2,3,4,5,10,11,12,13};
+    std::array<int,8> west{1,3,5,7,8,10,12,14};
 
     #pragma omp parallel
     {
@@ -50,37 +58,74 @@ std::vector<std::vector<Point>> vector_cellmap(HeightMap* heightmap, int interva
         #pragma omp for
         for (int i = 1; i <= num_contours; i++) 
         {
-            auto points = produce_cellmap(heightmap, heightmap->min + interval*i) ;
+            auto points = produce_cellmap(heightmap, heightmap->min + interval*i);
             std::vector<Point> line;
-            line.push_back(points.back());
+            int x;
-            points.pop_back();
+            int y;
-
+            int points_allocated = 0;
-            while (points.size() != 0){
+            x = points[0].x;
-                Point current_point = points.back();
+            y = points[0].y;
-                for (int j=0; j < points.size(); j++){
+            int current_case = points[0].mscase;
-                    Point next = points[j];
+            points[0].allocated = true;
-                    if (&next != &points.back()) {
+            line.push_back(points[0]);
-                        if (next.x +1 == current_point.x) {
+            for (int j = 0; j < points.size(); j++){
-                            line.push_back(next);
+                for (int k = 0; k < points.size(); k++){
-                            points.erase(points.begin()+j);
+                    Point* candidate = &points[k];
+                    if (!candidate->allocated) {
+                        if (candidate->x == x +1 && candidate->y == y /*&& is_in(current_case, east)*/) {
+                            candidate->allocated = true;
+                            x = candidate->x;
+                            y = candidate->y;
+                            current_case = candidate->mscase;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
                         }
-                        else if (next.x -1 == current_point.x) {
+                        else if (candidate->x == x -1 && candidate->y == y /*&& is_in(current_case, west)*/) {
-                            line.push_back(next);
+                            x = candidate->x;
-                            points.erase(points.begin()+j);
+                            y = candidate->y;
+                            current_case = candidate->mscase;
+                            candidate->allocated = true;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
                         }
-                        else if (next.y +1 == current_point.y) {
+                        else if (candidate->x == x && candidate->y == y + 1 /*&& is_in(current_case, north)*/) {
-                            line.push_back(next);
+                            x = candidate->x;
-                            points.erase(points.begin()+j);
+                            y = candidate->y;
+                            current_case = candidate->mscase;
+                            candidate->allocated = true;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
                         }
-                        else if (next.y -1 == current_point.y) {
+                        else if (candidate->x == x && candidate->y == y - 1 /*&& is_in(current_case, south)*/) {
-                            line.push_back(next);
+                            x = candidate->x;
-                            points.erase(points.begin()+j);
+                            y = candidate->y;
+                            current_case = candidate->mscase;
+                            candidate->allocated = true;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
                         }
-                        else {
+                    }
-                            vec_private.push_back(line);
+                }
-                            std::vector<Point> line;
+                if (j > points_allocated)
-                            line.push_back(points.back());
+                {
-                            points.pop_back();
+                    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);
+                            candidate->allocated = true;
+                            x = candidate->x;
+                            y = candidate->y;
+                            current_case = candidate->mscase;
+                            points_allocated++;
+                            break;
                         }
                     }
                 }
@@ -89,7 +134,6 @@ std::vector<std::vector<Point>> vector_cellmap(HeightMap* heightmap, int interva
         #pragma omp critical
 
         vector_contours.insert(vector_contours.end(), vec_private.begin(), vec_private.end());
-
     }
         return vector_contours;
 }
@@ -107,20 +151,35 @@ std::tuple<double, double> local_to_projected(double* geotransform, int x, int y
 constexpr std::tuple<double, double, double, double> marching_squares_lookup(int mcase)
 {
     switch (mcase) {
-        case 1: return {0, 0.5, 0.5, 0};
+        case 1:
-        case 2: return {1, 0.5, 0.5, 0};
+            return {0, 0.5, 0.5, 0};
-        case 3: return {0, 0.5, 1, 0};
+        case 14:
-        case 4: return {0.5, 1, 1, 0.5};
+            return {0.5, 0, 0, 0.5};
-        case 5: return {0, 0, 0, 0}; //FIXME
+        case 2: 
-        case 6: return {0.5, 1, 0.5, 0};
+            return {0.5, 0, 1, 0.5};
-        case 7: return {0, 0.5, 0.5, 1};
+        case 13:
-        case 8: return {0, 0.5, 0.5, 1};
+            return {1, 0.5, 0.5, 0};
-        case 9: return {0.5, 1, 0.5, 0};
+        case 3:
-        case 10: return {0, 0, 0, 0}; //FIXME
+            return {0, 0.5, 1, 0.5};
-        case 11: return {0.5, 1, 1, 0.5};
+        case 12:
-        case 12: return {0, 0.5, 1, 0.5};
+            return {1, 0.5, 0, 0.5};
-        case 13: return {0.5, 0, 1, 0.5};
+        case 4:
-        case 14: return {0, 0.5, 0.5, 0};
+            return {0.5, 1, 1, 0.5};
+        case 11:
+            return {1, 0.5, 0.5, 1};
+        case 5: 
+        case 10:
+            return {0, 0, 0, 0}; //FIXME
+        case 6: 
+            return {0.5, 1, 0.5, 0};
+        case 9:
+            return {0.5, 0, 0.5, 1};
+        case 7: 
+            return {0, 0.5, 0.5, 1};
+        case 8:
+            return {0.5, 0.5, 0, 0.5};
+
+        
     };
 }
 void write_output_file(std::vector<std::vector<Point>> all_points, const char *filepath, HeightMap* heightmap)
@@ -149,7 +208,7 @@ 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" );
@@ -171,64 +230,95 @@ 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];
+        
+        bool left_to_right = true;
+        
+        if ((points[0].y - points[1].y) < 0)
+            left_to_right = true;
+        else
+            left_to_right = false;
 
-        for (int i = 0; i < points.size(); i++) 
+        for (int k = 0; k < points.size(); k++)
         {
+            bool left_to_right = true;
+        
+            if ((points[k].x - points[k-1].x) < 0)
+                left_to_right = false;
+            bool top_to_bottom = true;
+            if ((points[k].y - points[k-1].y) < 0)
+                left_to_right = false;
 
-            //int x_raw = i%width;
+
-            //int y_raw = i/height;
+
-            int x_raw = points[i].x;
+            int x_raw = points[k].x;
-            int y_raw = points[i].y;
+            int y_raw = points[k].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 );
 
-
+            auto [x1, y1, x2, y2] = marching_squares_lookup(points[k].mscase);
-                
             
+            if (left_to_right or !top_to_bottom)
+            {
+                geometry->setPoint(geometry->getNumPoints(),x + (x1/6) ,y + (y1/6));
+                geometry->setPoint(geometry->getNumPoints(),x + (x2/6) ,y + (y2/6));
+            }
+            else {
+                geometry->setPoint(geometry->getNumPoints(),x + (x2/6) ,y + (y2/6));
+                geometry->setPoint(geometry->getNumPoints(),x + (x1/6) ,y + (y1/6));
+            }
         }
 
-                    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 );
 }
 
 int main(int argc, const char* argv[])
 {
-    const char* filepath = argv[1];
+    argh::parser cmdl(argv);
-    HeightMap map(filepath); 
-    
-    std::cout << "x: " << map.width << "    y: " << map.height << "\n";
-    std::cout << "max: " << map.max << "    min: " << map.min << "\n";
 
-    map.blur(0.8);
+    if (cmdl[{ "-h", "--help" }])
+    {
+        std::cout << "Usage:\n"
+            << "contour_creator [OPTIONS] <input_file>\n"
+            << "-o; --output <FILENAME.geojson> - File to write output to (Default: contours.geojson)\n"
+            << "-i; --interval <int> - Set the interval between contours (Default: 5)\n"
+            << "-b; --blur - Blur the image\n"
+            << "--stats - Print statistical information about the heightmap\n";
+            exit(0);
+    }
+    int interval;
+    cmdl({"-i", "--interval"}, 5) >> interval;
+    if (interval <= 0)
+        std::cerr << "Interval must be valid positive integer!" << "\n";
     
-    auto cellmap = produce_cellmap(&map, 40);
+    std::string output_file;
+    cmdl({"-o", "--output"}, "contours.geojson") >> output_file;
+
+    std::string input_file;
+    cmdl(1) >> input_file;
     
-    auto cellmaps = vector_cellmap(&map, 5);
+
-    write_output_file(cellmaps, "out.geojson", &map);
+    HeightMap map(input_file.c_str());
+    if (cmdl[{"-b", "--blur"}])
+        map.blur(0.8);
+    auto lines = create_lines(&map, interval);
+    write_output_file(lines, output_file.c_str(), &map);
+    std::cout << "Contours written to " << output_file << " 🗺️\n";
 }