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

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esther 2024-05-07 10:58:15 +02:00
commit 32a0b18f8e
5 changed files with 3202 additions and 81 deletions
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documentation/slides.md
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@ -5,16 +5,31 @@ author:
- Trygve og Esther
---
# What are contours
# Output of our program
pretty pictures
# Output of our program:
![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
# GDAL
What is it?
```cpp
int main(int argc, const char* argv[])
{
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

5
src/contour_creator.hh
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@ -43,13 +43,10 @@ class Point
int x;
int y;
int mscase;
Point * next;
Point * previous;
bool allocated = false;
Point(int x, int y, int mscase){
this -> x = x;
this -> y = y;
this -> mscase = mscase;
this -> next = nullptr;
this -> previous = nullptr;
};
};

155
src/main.cpp
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@ -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) +
(heightmap->get_pixel(x+1,y)>z)*2 +
(heightmap->get_pixel(x+1,y+1)>z)*4 +
(heightmap->get_pixel(x,y+1)>z)*8;
uint8_t result = (heightmap->get_pixel(x,y)>z)*8 +
(heightmap->get_pixel(x+1,y)>z)*4 +
(heightmap->get_pixel(x+1,y+1)>z)*2 +
(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>> 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<std::vector<Point>> vector_contours; // initiating a vector of contours
omp_set_num_threads(12);
std::vector<std::vector<Point>> vector_contours;
#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);
for (int j = 0; j < points.size(); j++){ //looping through all the points.
Point current = points[j]; // assigning an instance of Point class to a point.
//std::cout << points_allocated << " " << points.size() << "\n";
for (int k = 0; k < points.size(); k++){ // looping through all other points.
Point candidate = points[k];
if (candidate.next != nullptr) {
if (candidate.x +1 == current.x) {
current.next = &candidate;
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 -1 == current.x) {
current.next = &candidate;
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.y +1 == current.x) {
current.next = &candidate;
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.y -1 == current.x) {
current.next = &candidate;
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;
}
}
}
}
@ -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;
OGRLineString *geometry = new OGRLineString();
feature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
feature->SetField( "Name", j );
OGRFeature *feature;
OGRLineString *geometry = new OGRLineString();
feature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
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 = i%width;
//int y_raw = i/height;
int x_raw = points[i].x;
int y_raw = points[i].y;
int x_raw = points[k].x;
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 );
}
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 );
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 );
}
@ -216,8 +235,6 @@ int main(int argc, const char* argv[])
map.blur(0.8);
auto cellmap = produce_cellmap(&map, 40);
auto cellmaps = vector_cellmap(&map, 5);
write_output_file(cellmaps, "out.geojson", &map);
auto lines = create_lines(&map, 5);
write_output_file(lines, "out.geojson", &map);
}