diff --git a/README.md b/README.md
index a9abbb2..46f442e 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,7 @@ python las_outputs.py param-files/survey-1*.yaml param-files/survey-2*.yaml
 Example usage:
 
 ```
-C:/Python27/ArcGIS10.4/python generate_heatmaps.py param-files/survey-2*.yaml
+C:\Python27\ArcGIS10.5\python generate_heatmaps.py param-files\survey-2*.yaml
 
 ```
 
@@ -76,5 +76,13 @@ C:/Python27/ArcGIS10.4/python generate_heatmaps.py param-files/survey-2*.yaml
 Example usage:
 
 ```
-C:/Python27/ArcGIS10.4/python plot_heatmaps.py param-files/survey-2-avoca.yaml
+C:\Python27\ArcGIS10.5\python plot_heatmaps.py param-files\survey-2-avoca.yaml
 ```
+
+### 7. Export 0.7 m contour for DSAS trend analysis
+`extract_contours.py` extracts a predefined contour (say 0.7 m AHD) and outputs it in a format suitable for DSAS shoreline trend analysis.
+
+Example usage:
+```
+python extract_contours.py 
+```
\ No newline at end of file
diff --git a/generate_heatmaps.py b/generate_heatmaps.py
index 888d794..60f6809 100644
--- a/generate_heatmaps.py
+++ b/generate_heatmaps.py
@@ -72,10 +72,10 @@ def process(yaml_name):
         raise ValueError('No previous survey date provided')
 
     # Set paths for raster files
-    current_raster = os.path.join(input_tif_dir, base_name + '.tif')
+    current_raster = os.path.join(input_tif_dir, base_name + '_DEM.tif')
     previous_base_name = re.sub('\d+', previous_date, base_name)
-    previous_raster = os.path.join(input_tif_dir, previous_base_name + '.tif')
-    heatmap_raster = os.path.join(output_tif_dir, base_name + '.tif')
+    previous_raster = os.path.join(input_tif_dir, previous_base_name + '_DEM.tif')
+    heatmap_raster = os.path.join(output_tif_dir, base_name + '_heatmap.tif')
 
     print('processing {}'.format(beach))
 
diff --git a/las_outputs.py b/las_outputs.py
index 3487ad7..2819933 100644
--- a/las_outputs.py
+++ b/las_outputs.py
@@ -262,7 +262,7 @@ def process(yaml_file):
 
     # Make a raster from point cloud
     print('Creating heat map raster...')
-    tif_name = os.path.join(output_tif_dir, las_basename + '.tif')
+    tif_name = os.path.join(output_tif_dir, las_basename + '_DEM.tif')
     call_lastools('las2dem', input=las_data, output=tif_name,
                   args=['-step', 1, '-keep_class', 2], verbose=False)
     # IF THIS STEP ISN'T WORKING:
diff --git a/plot_heatmaps.py b/plot_heatmaps.py
index d1c0422..2c89382 100644
--- a/plot_heatmaps.py
+++ b/plot_heatmaps.py
@@ -70,7 +70,7 @@ def process(yaml_name):
         raise ValueError('No previous survey date provided')
 
     # Set paths for raster files
-    heatmap_raster = os.path.join(input_tif_dir, base_name + '.tif')
+    heatmap_raster = os.path.join(input_tif_dir, base_name + '_heatmap.tif')
 
     print('processing {}'.format(beach))
     mxd = arcpy.mapping.MapDocument(mxd_name)