diff --git a/Sources/GeoDrawer/GeoDrawer.swift b/Sources/GeoDrawer/GeoDrawer.swift
index 8eeecc3..d6da4e3 100644
--- a/Sources/GeoDrawer/GeoDrawer.swift
+++ b/Sources/GeoDrawer/GeoDrawer.swift
@@ -220,8 +220,11 @@ extension GeoDrawer {
     // 3. Now translate the projected points into point coordinates to draw
     let converted = projected
       .map { (unproj, projected) -> (Point, Point?, Grouping) in
+        assert(unproj.isGood)
         if let projected {
-          return (unproj, projection.translate(projected, to: size, zoomTo: zoomTo, insets: insets), projection.willWrap(unproj) ? .wrapped : .notWrapped)
+          let proj = projection.translate(projected, to: size, zoomTo: zoomTo, insets: insets)
+          assert(proj.isGood)
+          return (unproj, proj, projection.willWrap(unproj) ? .wrapped : .notWrapped)
         } else {
           return (unproj, nil, .notProjected)
         }
@@ -265,7 +268,11 @@ extension GeoDrawer {
           // When "resuming" the same group, connect with the previous points
           // in the group, but interpolate again.
           let interpolated = Interpolator.interpolate(from: last, to: unproj, maxDiff: 0.0025, projector: projection.project(_:))
-          let translated = interpolated.map { ($0.0, projection.translate($0.1, to: size, zoomTo: zoomTo, insets: insets)) }
+          let translated = interpolated.map {
+            let translated = projection.translate($0.1, to: size, zoomTo: zoomTo, insets: insets)
+            assert(translated.isGood)
+            return ($0.0, translated)
+          }
           new.append(contentsOf: translated)
         }
         if let proj {
@@ -287,3 +294,9 @@ extension GeoDrawer {
     return [wraps.map(\.1), unwraps.map(\.1)].filter { !$0.isEmpty }
   }
 }
+
+fileprivate extension Point {
+  var isGood: Bool {
+    !x.isNaN && !y.isNaN && !x.isInfinite && !y.isInfinite
+  }
+}
diff --git a/Sources/GeoProjector/Projection.swift b/Sources/GeoProjector/Projection.swift
index b1e0647..cf1a121 100644
--- a/Sources/GeoProjector/Projection.swift
+++ b/Sources/GeoProjector/Projection.swift
@@ -91,11 +91,12 @@ extension Projection {
       height: size.height - insets.top - insets.bottom
     )
     let pointInAvailable: Point
-    if let zoomTo {
+    if let zoomTo, zoomTo.size != .zero {
       pointInAvailable = zoomedTranslate(point, zoomTo: zoomTo, to: availableSize)
     } else {
       pointInAvailable = simpleTranslate(point, to: availableSize)
     }
+    assert(pointInAvailable.isGood)
     
     let x: Double = pointInAvailable.x + insets.left
     let y: Double
@@ -104,7 +105,9 @@ extension Projection {
 #else
     y = (availableSize.height - pointInAvailable.y) + insets.top
 #endif
-    return Point(x: x, y: y)
+    let result = Point(x: x, y: y)
+    assert(result.isGood)
+    return result
   }
   
   private func simpleTranslate(_ point: Point, to size: Size) -> Point {
@@ -137,6 +140,7 @@ extension Projection {
   }
   
   private func zoomedTranslate(_ point: Point, zoomTo: Rect, to size: Size) -> Point {
+    assert(zoomTo.size != .zero)
     let myRatio = zoomTo.size.aspectRatio
     let targetRatio = size.aspectRatio
     
@@ -183,3 +187,9 @@ extension Size {
     width / height
   }
 }
+
+fileprivate extension Point {
+  var isGood: Bool {
+    !x.isNaN && !y.isNaN && !x.isInfinite && !y.isInfinite
+  }
+}