diff --git a/src/main/java/de/blau/android/dialogs/BarometerCalibration.java b/src/main/java/de/blau/android/dialogs/BarometerCalibration.java
index 54951e8fc7..81f4893c62 100644
--- a/src/main/java/de/blau/android/dialogs/BarometerCalibration.java
+++ b/src/main/java/de/blau/android/dialogs/BarometerCalibration.java
@@ -1,5 +1,8 @@
 package de.blau.android.dialogs;
 
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
 import android.annotation.SuppressLint;
 import android.content.Intent;
 import android.os.Bundle;
@@ -30,6 +33,8 @@ public class BarometerCalibration extends ImmersiveDialogFragment {
 
     private static final String TAG = "fragment_calibration_form";
 
+    private static final Pattern FLOAT_PATTERN = Pattern.compile("[^0-9]*([0-9]+[.][0-9]*)[^0-9]*");
+
     /**
      * Display a dialog allowing barometer calibration
      * 
@@ -93,7 +98,12 @@ public AppCompatDialog onCreateDialog(Bundle savedInstanceState) {
                     intent.putExtra(TrackerService.CALIBRATE_HEIGHT_KEY, Integer.parseInt(calibrationValue));
                     break;
                 case 1: // reference pressure
-                    intent.putExtra(TrackerService.CALIBRATE_P0_KEY, Float.parseFloat(calibrationValue.substring(0, calibrationValue.length() - 2).trim()));
+                    Matcher matcher = FLOAT_PATTERN.matcher(calibrationValue);
+                    if (matcher.find()) {
+                        intent.putExtra(TrackerService.CALIBRATE_P0_KEY, Float.parseFloat(matcher.group(1)));
+                    } else {
+                        throw new NumberFormatException(calibrationValue);
+                    }
                     break;
                 default: // GNSS
                     // this is the default
diff --git a/src/main/java/de/blau/android/easyedit/EasyEditManager.java b/src/main/java/de/blau/android/easyedit/EasyEditManager.java
index d48ef0b804..c28cdf39b6 100644
--- a/src/main/java/de/blau/android/easyedit/EasyEditManager.java
+++ b/src/main/java/de/blau/android/easyedit/EasyEditManager.java
@@ -327,7 +327,7 @@ protected void onPostExecute(SerializableState state) {
                                         getMain().startSupportActionMode(cb);
                                         return;
                                     } catch (ClassNotFoundException | NoSuchMethodException | SecurityException | InstantiationException
-                                            | IllegalAccessException | IllegalArgumentException | InvocationTargetException exception) {
+                                            | IllegalAccessException | IllegalArgumentException | InvocationTargetException | NullPointerException exception) {
                                         Log.e(DEBUG_TAG, "Restarting " + restartActionModeCallbackName + " received " + exception.getClass().getCanonicalName()
                                                 + " " + exception.getMessage());
                                     }
diff --git a/src/main/java/de/blau/android/resources/TileLayerSource.java b/src/main/java/de/blau/android/resources/TileLayerSource.java
index 59580b354b..bf0255a06b 100644
--- a/src/main/java/de/blau/android/resources/TileLayerSource.java
+++ b/src/main/java/de/blau/android/resources/TileLayerSource.java
@@ -2252,7 +2252,7 @@ public int getMinZoom() {
      */
     public void setMinZoom(int newZoomLevelMin) {
         synchronized (this) {
-            if (offsets != null && zoomLevelMin != newZoomLevelMin) {
+            if (offsets != null && zoomLevelMin != newZoomLevelMin && zoomLevelMax > newZoomLevelMin) {
                 Offset[] tempOffsets = new Offset[zoomLevelMax - newZoomLevelMin + 1];
                 int destOffset = Math.max(0, zoomLevelMin - newZoomLevelMin);
                 System.arraycopy(offsets, Math.max(0, newZoomLevelMin - zoomLevelMin), tempOffsets, destOffset, tempOffsets.length - destOffset);
@@ -2280,7 +2280,7 @@ public int getMaxZoom() {
      */
     public void setMaxZoom(int newZoomLevelMax) {
         synchronized (this) {
-            if (offsets != null && zoomLevelMax != newZoomLevelMax) {
+            if (offsets != null && zoomLevelMax != newZoomLevelMax && newZoomLevelMax > zoomLevelMin) {
                 Offset[] tempOffsets = new Offset[newZoomLevelMax - zoomLevelMin + 1];
                 System.arraycopy(offsets, 0, tempOffsets, 0, Math.min(offsets.length, tempOffsets.length));
                 offsets = tempOffsets;