diff --git a/src/main.cpp b/src/main.cpp
index a936309..5d33e73 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -12,14 +12,15 @@
 
 CaseMap produce_casemap(HeightMap* heightmap, float z)
 {
-    uint8_t *cases = (uint8_t *) CPLMalloc(sizeof(uint8_t)*(heightmap->width-1)*(heightmap->height-1));
-    for (int i = 0; i<(heightmap->width-1)*(heightmap->height-1); i++) {
-        int y = i/(heightmap->height-1);
-        int x = i%(heightmap->height-1);
-        uint8_t result = (heightmap->get_pixel(x,y+1)>z) + 
-        (heightmap->get_pixel(x+1,y+1)>z)*2 +
-        (heightmap->get_pixel(x+1,y)>z)*4 +
-        (heightmap->get_pixel(x,y)>z)*8;
+    int length = (heightmap->width-1)*(heightmap->height-1);
+    uint8_t *cases = (uint8_t *) CPLMalloc(sizeof(uint8_t)*length);
+    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;
         *(cases + i) = result;
     }
     
@@ -28,7 +29,7 @@ CaseMap produce_casemap(HeightMap* heightmap, float z)
 
 }
 
-void write_output_file(CaseMap* casemap)
+void write_output_file(CaseMap* casemap, const char *filepath)
 {
 
     const char *pszDriverName = "ESRI Shapefile";
@@ -45,7 +46,7 @@ void write_output_file(CaseMap* casemap)
 
     GDALDataset *poDS;
 
-    poDS = poDriver->Create( "point_out.shp", 0, 0, 0, GDT_Unknown, NULL );
+    poDS = poDriver->Create( filepath, 0, 0, 0, GDT_Unknown, NULL );
     if( poDS == NULL )
     {
         printf( "Creation of output file failed.\n" );
@@ -54,7 +55,7 @@ void write_output_file(CaseMap* casemap)
 
     OGRLayer *poLayer;
 
-    poLayer = poDS->CreateLayer( "point_out", &casemap->reference_system, wkbPoint, NULL );
+    poLayer = poDS->CreateLayer( "contours", &casemap->reference_system, wkbPoint, NULL );
     if( poLayer == NULL )
     {
         printf( "Layer creation failed.\n" );
@@ -74,8 +75,8 @@ void write_output_file(CaseMap* casemap)
     for (int i = 0; i<casemap->height*casemap->width; i++) {
         if (*(casemap->cases + i) != 0 && *(casemap->cases + i) != 15)
         {
-            int x_int = i%casemap->height;
-            int y_int = casemap->height*casemap->width - i/casemap->height;
+            int x_int = i%casemap->width;
+            int y_int = casemap->height*casemap->width - i/casemap->width;
             double x = double(x_int);
             double y = double(y_int);
 
@@ -128,7 +129,7 @@ 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";
     
-    auto casemap = produce_casemap(&map, 40.0);
+    auto casemap = produce_casemap(&map, 40);
     /*
     for (int y = 0; y < casemap.height; y++)
     {
@@ -141,5 +142,5 @@ int main(int argc, const char* argv[])
        //std::cout << "\n";
     }
     */
-    write_output_file(&casemap);
+    write_output_file(&casemap, "out.shp");
 }
\ No newline at end of file