Tried fixing gdal bullshit in steepnes method

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/HeightMap.cpp

@@ -1,11 +1,12 @@
+#include <cstddef>
 #include <gdal/cpl_conv.h>
 #include <iostream>
 #include <stdexcept>
-
+#include <omp.h>
 #include <gdal/gdal.h>
 #include "gdal/gdal_priv.h"
 #include <gdal/gdal_frmts.h>
-
+//#include "matplotlibcpp.h"
 #include "contour_creator.hh"
 
 
@@ -32,6 +33,7 @@ HeightMap::HeightMap(const char* filepath)
     //https://gdal.org/api/gdaldataset_cpp.html#_CPPv4N11GDALDataset15GetGeoTransformEPd
     this->geotransform = (double *) CPLMalloc(sizeof(double)*6);
     this->reference_system = *(file->GetSpatialRef());
+    this->filepath = filepath;
 
     file->GetGeoTransform(this->geotransform);
     
@@ -41,6 +43,7 @@ HeightMap::HeightMap(const char* filepath)
                     0, 0 );
     if (error) { throw std::runtime_error("Could not read tif file!"); }
     band->FlushCache();
+    const int size = this->width*this->height;
 }
 float HeightMap::get_pixel(int x, int y)
 {
@@ -48,4 +51,143 @@ float HeightMap::get_pixel(int x, int y)
     int offset = ((this->width * y) + x);
     //std::cout << "  offset: " << offset << " " << x << ","<< y;
     return *(this->data + offset);
+}
+
+void HeightMap::blur(float standard_deviation)
+{
+    // standard_deviation does not do anything yet. This is currently a simple box blur
+    int kernel_height = 5;
+    int kernel_width = 5;
+    int kernel_size = kernel_height*kernel_width;
+    float* kernel = (float*) CPLMalloc(sizeof(float)*kernel_size);
+    for (int i=0; i<kernel_size; i++)
+    {
+        *(kernel + i) = 1.0;
+    }
+
+    float* blurred = new float[this->width*this->height];
+    #pragma omp parallel
+    {
+    #pragma omp for
+    for (int i = 0; i < this->height * this->width; i++)
+    {
+        float blurred_pixel = 0;
+        for (int j = 0; j < kernel_size; j++)
+        {
+            int x = j%kernel_width - kernel_width/2 + i%this->width;
+            int y = j/kernel_width - kernel_height/2 + i/this->width;
+            if (x<0 || x>=this->width)
+            {
+                x = 0;
+            }
+            
+            if (y<0 || y>=this->height)
+            {
+                y = 0;
+            }
+            blurred_pixel += this->get_pixel(x, y);
+        }
+        *(blurred + i) = blurred_pixel/float(kernel_size);
+    }
+    }
+    free(this->data);
+    this->data = blurred;
+    blurred = nullptr;
+}
+
+void HeightMap::statistics()
+{
+
+    float avg = 0;
+    float var = 0;
+    float std = 0;
+
+    for (int i = 0; i < this->width*this->height; i++)
+        {int x = i%this->width;
+        int y = i/this->width;
+            if (x<0 || x>=this->width)
+            {
+                x = 0;
+            }
+            
+            if (y<0 || y>=this->height)
+            {
+                y = 0;
+            }
+        avg += this->get_pixel(x, y);}
+        //std::cout << this->get_pixel(x, y);}
+    
+    avg = avg/(this->width*this->height);
+    std::cout << "Average value: " << avg <<"\n";
+
+    for (int i = 0; i < this->width*this->height; i++)
+    {
+        int x = i%this->width;
+        int y = i/this->width;
+        var += (avg - this->get_pixel(x, y))*(avg - this->get_pixel(x, y));
+    }
+    std = sqrt(var)/(this->width*this->height-1);
+    var = var / (this->width*this->height-1);
+    std::cout << "std: " << std << "\n";
+    std::cout << "var: " << var << "\n";
+};
+
+
+void HeightMap::calculate_steepness()
+{
+    int kernel_height = 5;
+    int kernel_width = 5;
+    int kernel_size = kernel_height*kernel_width;
+
+    float* kernel = new float[sizeof(float)*kernel_size];
+    float* steepness = new float[this->width*this->height];
+    #pragma omp parallel
+    {
+    #pragma omp for
+    for (int i = 0; i < this->height * this->width; i++)
+    {
+        int x = i%this->width;
+        int y = i/this->width;
+        float max = 0;
+        float min = 0;
+        for (int j = 0; j < kernel_size; j++)
+        {
+            if (this->get_pixel(x, y) > max)
+            {
+                max = get_pixel(x, y);
+            }
+
+            if (this->get_pixel(x, y) < min)
+            {
+                min = get_pixel(x, y);
+            }
+
+            if (x<0 || x>=this->width)
+            {
+                x = 0;
+            }
+            
+            if (y<0 || y>=this->height)
+            {
+                y = 0;
+            }
+            
+        }
+        steepness[i] = max - min;
+    }
+    }
+    GDALAllRegister();
+    GDALDataset *original_file = (GDALDataset *) GDALOpen( filepath, GA_ReadOnly );
+
+    const char * filename = "steepness.tif";
+    auto driver = GetGDALDriverManager()->GetDriverByName("GeoRaster");
+    GDALDataset *file;
+    file = driver->CreateCopy("steepness.tif", original_file, FALSE, NULL, NULL, NULL);
+
+    file->AddBand(GDT_Float32, NULL);
+    GDALRasterBand *band = file->GetRasterBand(0);
+    CPLErr error = band->RasterIO( GF_Write, 0, 0, this->width, this->height,
+                    steepness, this->width, this->height, GDT_Float32,
+                    0, 0 );
+    GDALClose(file);
 }

src/contour_creator.hh

@@ -16,9 +16,12 @@ class HeightMap
         float min; //!< Minimum value in image
         float max; //!< Maximum value in image
         OGRSpatialReference reference_system;
-
         HeightMap(const char* filepath);
+        const char* filepath;
         float get_pixel(int x,int y);
+        void blur(float standard_deviation);
+        void statistics();
+        void calculate_steepness();
 };
 
 /**
@@ -34,4 +37,18 @@ class CellMap
         OGRSpatialReference reference_system;
         CellMap(int width, int height, uint8_t* cells, OGRSpatialReference reference_system, double* geotransform);
         int get_cell(int x,int y);
-};
+};
+
+class Point
+{
+    public:
+        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

@@ -1,6 +1,9 @@
 #include "contour_creator.hh"
 #include <gdal/ogr_api.h>
 #include "ogrsf_frmts.h"
+#include <gdal/ogr_core.h>
+#include <gdal/ogr_feature.h>
+#include <gdal/ogr_geometry.h>
 #include <iostream>
 #include <ostream>
 #include <vector>
@@ -9,43 +12,108 @@
 #include "gdal/gdal_priv.h"
 #include <gdal/gdal_frmts.h>
 #include <omp.h>
+//#include "matplotlibcpp.h"
+//namespace plt = matplotlibcpp;
 
-CellMap produce_cellmap(HeightMap* heightmap, float z)
+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; // 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);
-        *(cells + i) = result;
+        if (result != 0 and result != 15 ) {
+            points.push_back(Point(x, y, result));
+        };
     }
-    
+    return points;
-    return CellMap(heightmap->width-1, heightmap->height-1, cells, heightmap->reference_system, heightmap->geotransform);
-
-
 }
 
-std::vector<CellMap> vector_cellmap(HeightMap* heightmap, int interval)
+std::vector<std::vector<Point>> create_lines(HeightMap* heightmap, int interval)
 {
     int num_contours = (heightmap->max - heightmap->min)/interval;
-    std::vector<CellMap> vector_contours;
+    std::vector<std::vector<Point>> vector_contours;
-    omp_set_num_threads(12);
 
     #pragma omp parallel
     {
-        std::vector<CellMap> vec_private;
+        std::vector<std::vector<Point>> vec_private;
         #pragma omp for
         for (int i = 1; i <= num_contours; i++) 
         {
-            vec_private.push_back(produce_cellmap(heightmap, heightmap->min + interval*i));
+            auto points = produce_cellmap(heightmap, heightmap->min + interval*i);
+            std::vector<Point> line;
+            int x;
+            int y;
+            int points_allocated = 0;
+            x = points[0].x;
+            y = points[0].y;
+            points[0].allocated = true;
+            line.push_back(points[0]);
+            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 == x -1 && candidate->y == y) {
+                            x = candidate->x;
+                            y = candidate->y;
+                            candidate->allocated = true;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
+                        }
+                        else if (candidate->x == x && candidate->y == y + 1) {
+                            x = candidate->x;
+                            y = candidate->y;
+                            candidate->allocated = true;
+                            line.push_back(*candidate);
+                            points_allocated++;
+                            break;
+                        }
+                        else if (candidate->x == x && candidate->y == y - 1) {
+                            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;
+                        }
+                    }
+                }
+            }
         }
         #pragma omp critical
-        vector_contours.insert(vector_contours.end(), vec_private.begin(), vec_private.end());
 
+        vector_contours.insert(vector_contours.end(), vec_private.begin(), vec_private.end());
     }
         return vector_contours;
 }
@@ -53,17 +121,36 @@ std::vector<CellMap> vector_cellmap(HeightMap* heightmap, int interval)
 std::tuple<double, double> local_to_projected(double* geotransform, int x, int y)
 {
     return {
-            geotransform[1] * x + geotransform[2] * y +
+        geotransform[1] * x + geotransform[2] * y +
-            geotransform[1] * 0.5 + geotransform[2] * 0.5 + geotransform[0],
+        geotransform[1] * 0.5 + geotransform[2] * 0.5 + geotransform[0],
-            geotransform[4] * x + geotransform[5] * y +
+        geotransform[4] * x + geotransform[5] * y +
-            geotransform[4] * 0.5 + geotransform[5] * 0.5 + geotransform[3]
+        geotransform[4] * 0.5 + geotransform[5] * 0.5 + geotransform[3]
-            };
+        };
 }
 
-void write_output_file(std::vector<CellMap> cellmaps, const char *filepath)
+constexpr std::tuple<double, double, double, double> marching_squares_lookup(int mcase)
+{
+    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, 0.5};
+        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};
+        case 7: return {0, 0.5, 0.5, 1};
+        case 8: return {0, 0.5, 0.5, 1};
+        case 9: return {0.5, 1, 0.5, 0};
+        case 10: return {0, 0, 0, 0}; //FIXME
+        case 11: return {0.5, 1, 1, 0.5};
+        case 12: return {0, 0.5, 1, 0.5};
+        case 13: return {0.5, 0, 1, 0.5};
+        case 14: return {0, 0.5, 0.5, 0};
+    };
+}
+void write_output_file(std::vector<std::vector<Point>> all_points, const char *filepath, HeightMap* heightmap)
 {
 
-    const char *pszDriverName = "ESRI Shapefile";
+    const char *pszDriverName = "GeoJSON";
     GDALDriver *poDriver;
 
     GDALAllRegister();
@@ -86,7 +173,7 @@ void write_output_file(std::vector<CellMap> cellmaps, const char *filepath)
 
     OGRLayer *poLayer;
 
-    poLayer = poDS->CreateLayer( "contours", &(cellmaps[0]).reference_system, wkbPoint, NULL );
+    poLayer = poDS->CreateLayer( "contours", &heightmap->reference_system, wkbLineString, NULL );
     if( poLayer == NULL )
     {
         printf( "Layer creation failed.\n" );
@@ -102,56 +189,42 @@ void write_output_file(std::vector<CellMap> cellmaps, const char *filepath)
         printf( "Creating Name field failed.\n" );
         exit( 1 );
     }
-    for (int j = 0; j < cellmaps.size(); j++)
+    int width = heightmap->width -1;
+    int height = heightmap->height -1;
+    int size = width * height;
+
+    for (int j = 0; j < all_points.size(); j++)
     {
-        CellMap* cellmap = &cellmaps[j];
+        OGRFeature *feature;
-        for (int i = 0; i<cellmap->height*cellmap->width; i++) {
+        OGRLineString *geometry = new OGRLineString();
-            if (*(cellmap->cells + i) != 0 && *(cellmap->cells + i) != 15)
+        feature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
-            {
+        feature->SetField( "Name", j );
-                OGRFeature *poFeature;
-                poFeature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
-                poFeature->SetField( "Name", *(cellmap->cells + i) );
 
-                //OGRSpatialReference local;
+        std::vector<Point> points = all_points[j];
 
-                //auto poCT = OGRCreateCoordinateTransformation( &local, &cellmap->reference_system );
+        for (int k = 0; k < points.size(); k++)
-                
+        {
-                /*
+            int x_raw = points[k].x;
-                if( poCT == NULL || !poCT->Transform( 1, &x, &y ) )
+            int y_raw = points[k].y;
-                    printf( "Transformation failed.\n" );
+            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) );
-                OGRPoint pt;
+            geometry->setPoint(geometry->getNumPoints(),x ,y );
-
-                int x_raw = i%cellmap->width;
-                int y_raw = i/cellmap->width;
-                auto [x, y] = local_to_projected(cellmap->geotransform, x_raw, y_raw);
-
-                pt.setX( x );
-                pt.setY( y );
-
-                poFeature->SetGeometry( &pt );
-
-                if( poLayer->CreateFeature( poFeature ) != OGRERR_NONE )
-                {
-                    printf( "Failed to create feature in shapefile.\n" );
-                    exit( 1 );
-                }
-
-                OGRFeature::DestroyFeature( poFeature );
-            }
         }
+
+        if ( feature->SetGeometry(geometry) != OGRERR_NONE)
+        {
+            printf( "Failed to set geometry.\n" );
+            exit( 1 );
+        }
+        OGRGeometryFactory::destroyGeometry(geometry);
+        if( poLayer->CreateFeature( feature ) != OGRERR_NONE )
+        {
+            printf( "Failed to create feature in shapefile.\n" );
+            exit( 1 );
+        }
+        OGRFeature::DestroyFeature( feature );
     }
-
     GDALClose( poDS );
-    /*
-    OGRDataSourceH datasource = OGR_Dr_CreateDataSource(OGRGetDriverByName("GeoJSON"), "contour.geojson", new char*);
-    OGRSpatialReference reference_system = cellmap->reference_system;
-    OGRLayerH layer = OGR_DS_CreateLayer(datasource, "contour", &reference_system, wkbLineString25D, new char*);
-    
-    auto feature = OGR_F_Create(OGR_L_GetLayerDefn(static_cast<OGRLayerH>(layer)));
-
-    OGRGeometryH geometry = OGR_G_CreateGeometry(wkbLineString25D);
-    */
 }
 
 int main(int argc, const char* argv[])
@@ -161,21 +234,20 @@ int main(int argc, const char* argv[])
     
     std::cout << "x: " << map.width << "    y: " << map.height << "\n";
     std::cout << "max: " << map.max << "    min: " << map.min << "\n";
+
+    map.blur(0.8);
+
+    map.statistics();
+
+    map.calculate_steepness();
     
-    auto cellmap = produce_cellmap(&map, 40);
+    auto lines = create_lines(&map, 5);
-    /*
+    write_output_file(lines, "out.geojson", &map);
-    for (int y = 0; y < cellmap.height; y++)
+
-    {
+
-        for (int x = 0; x < cellmap.width; x++)
+    std::vector<int> y = {1, 2, 3};
-        {
+    //plt::plot(y, "bo-");
-            if (cellmap.get_cell(x, y) && cellmap.get_cell(x, y)!=15) {
+    //plt::show();
-                std::cout << x << ","<< y << "=" << cellmap.get_cell(x, y) << " ";
+
-            }
+    return 0;
-        }
-       //std::cout << "\n";
-    }
-    */
-    
-    auto cellmaps = vector_cellmap(&map, 5);
-    write_output_file(cellmaps, "out.shp");
 }