diff --git a/lib/validate.py b/lib/validate.py
new file mode 100644
index 0000000..c74efb6
--- /dev/null
+++ b/lib/validate.py
@@ -0,0 +1,30 @@
+from math import cos, radians
+from osgeo import ogr, osr
+
+METERS_PER_DEGREE_LAT = 111132
+
+def validate_one_line(fields):
+    if int(fields['from']) < 0 or int(fields['to']) < 0:
+        print('Negative housenumber, skipping')
+        return False
+
+    number_range = abs(int(fields['from']) - int(fields['to']))
+    step_size = 1 if fields['interpolation'] == 'all' else 2
+    length = length_of_wkt_line_in_meters(fields['geometry'])
+    if number_range > 0 and length < 10:
+        print('Interpolation less than 10 meters, skipping')
+        return False
+
+    return True
+
+def length_of_wkt_line_in_meters(wkt_line):
+    line = ogr.CreateGeometryFromWkt(wkt_line)
+
+    center_lat = line.Centroid().GetY()
+
+    meters_per_degree_lon = METERS_PER_DEGREE_LAT * cos(radians(center_lat))
+
+    length_degrees = line.Length()
+    length_meters = length_degrees * (METERS_PER_DEGREE_LAT + meters_per_degree_lon) / 2
+
+    return length_meters
diff --git a/tests/test_validate.py b/tests/test_validate.py
new file mode 100644
index 0000000..6c4805c
--- /dev/null
+++ b/tests/test_validate.py
@@ -0,0 +1,33 @@
+from lib.validate import validate_one_line, length_of_wkt_line_in_meters
+
+def test_validate_one_line():
+    line = {
+        'from': '53', 
+        'to': '99', 
+        'interpolation': 'odd', 
+        'street': 'Pope Rd', 
+        'city': 'Middlesex', 
+        'state': 'MA', 
+        'postcode': '01720', 
+        'geometry': 'LINESTRING(-71.407890 42.480238,-71.407870 42.480264,-71.407563 42.480689,-71.407061 42.481394,-71.406843 42.481731,-71.406309 42.482496,-71.406032 42.482864,-71.405533 42.483570,-71.405220 42.483994,-71.404987 42.484331,-71.404723 42.484835,-71.404551 42.485166,-71.404495 42.485385)'
+    }
+    assert(validate_one_line(line)) == True
+
+    line['from'] = '-1'
+    assert(validate_one_line(line)) == False
+    line['from'] = '53'
+
+    line['geometry'] = "LINESTRING(-64.937000 18.344883,-64.937000 18.344883)"
+    assert(validate_one_line(line)) == False
+    
+
+
+def test_length_of_wkt_line_in_meters():
+    wkt_line = "LINESTRING(-64.937000 18.344883,-64.937000 18.344883)"
+    assert(length_of_wkt_line_in_meters(wkt_line)) == 0.0
+
+    wkt_line = "LINESTRING(-71.196131 42.409367,-71.196170 42.409260)"
+    assert(round(length_of_wkt_line_in_meters(wkt_line))) == 11
+
+    wkt_line = "LINESTRING(-64.937000 18.344883,-64.936982 18.344751,-64.936960 18.344663,-64.936949 18.344617)"
+    assert(round(length_of_wkt_line_in_meters(wkt_line))) == 29
diff --git a/tiger_address_convert.py b/tiger_address_convert.py
index bdc6c57..3750f08 100755
--- a/tiger_address_convert.py
+++ b/tiger_address_convert.py
@@ -15,6 +15,7 @@
 
 from lib.parse import parse_shp_for_geom_and_tags
 from lib.convert import addressways, compile_nodelist, compile_waylist
+from lib.validate import validate_one_line
 
 def shape_to_csv(shp_filename, csv_filename):
     """
@@ -46,7 +47,9 @@ def shape_to_csv(shp_filename, csv_filename):
     with open(csv_filename, 'w', encoding="utf8") as csv_file:
         csv_writer = csv.DictWriter(csv_file, delimiter=';', fieldnames=fieldnames)
         csv_writer.writeheader()
-        csv_writer.writerows(csv_lines)
+        for csv_line in csv_lines:
+            if validate_one_line(csv_line):
+                csv_writer.writerow(csv_line)
 
 if len(sys.argv) < 3:
     print("%s input.shp output.csv" % sys.argv[0])