diff --git a/classesphp/classe_analise.php b/classesphp/classe_analise.php
index dd5d913..7033b1d 100644
--- a/classesphp/classe_analise.php
+++ b/classesphp/classe_analise.php
@@ -1180,7 +1180,7 @@ nome do layer criado com o buffer.
 				$dd2->setXY(($poPoint->x + $distancia), $poPoint->y);
 				$dd2->project($projOutObj,$projInObj);
 				$d = $dd1->distanceToPoint($dd2);
-				if ($d < 0){$d = $d * -1;}
+				if ($distancia < 0){$d = $d * -1;}
 				//calcula a distancia 29100
 				//gera o buffer
 				$buffers[] = $shape->buffer($d);
diff --git a/ferramentas/buffer/index.js b/ferramentas/buffer/index.js
index f11045e..83f769d 100644
--- a/ferramentas/buffer/index.js
+++ b/ferramentas/buffer/index.js
@@ -64,7 +64,7 @@ function criarbuffer()
 	$i("fim").innerHTML ="";
 	var distancia = $i("d").value
 	tema = $i("temasComSel").value
-	if (distancia*1 > 0)
+	if (distancia*1 != 0)
 	{
 		aguarde("block")
 		var fim = function(retorno)
@@ -82,4 +82,6 @@ function criarbuffer()
 		//cp.set_persistent_connection(true);
 		cp.call(p,"criaBuffer",fim);
 	}
+	else
+	{alert("Distancia invalida")}
 }
--
libgit2 0.21.2