From 5758e6d9de92bfccd81727778f25a1619a809367 Mon Sep 17 00:00:00 2001
From: Dane Springmeyer <dane@dbsgeo.com>
Date: Tue, 18 Dec 2012 11:57:45 -0800
Subject: [PATCH] Loosen simplification factor to 1/20 of pixel (master branch)
 - closes #1639

---
 plugins/input/postgis/postgis_datasource.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/plugins/input/postgis/postgis_datasource.cpp b/plugins/input/postgis/postgis_datasource.cpp
index 700615dcb..5197fa6e6 100644
--- a/plugins/input/postgis/postgis_datasource.cpp
+++ b/plugins/input/postgis/postgis_datasource.cpp
@@ -635,7 +635,10 @@ featureset_ptr postgis_datasource::features(const query& q) const
             s << "\"" << geometryColumn_ << "\"";
 
             if (simplify_geometries_) {
-                const double tolerance = std::min(px_gw, px_gh) / 2.0;
+                // 1/20 of pixel seems to be a good compromise to avoid
+                // drop of collapsed polygons.
+                // See https://github.com/mapnik/mapnik/issues/1639
+                const double tolerance = std::min(px_gw, px_gh) / 20.0;
                 s << ", " << tolerance << ")";
             }