diff --git a/resources/public/css/style.css b/resources/public/css/style.css
index 4117c97..de8c37f 100644
--- a/resources/public/css/style.css
+++ b/resources/public/css/style.css
@@ -35,7 +35,7 @@ footer a {
 h1, h2, h3, h4, h5, h6 {
   width: 100%;
   margin: 0;
-  padding-left: 10%;
+  padding: 0.5em 10%;
   text-align: left;
   background-color: #3298dc;
   color: white;
@@ -44,3 +44,19 @@ h1, h2, h3, h4, h5, h6 {
 samp {
   background-color: #b0b0ff;
 }
+
+#error
+{
+  background-color: maroon;
+  color: white;
+  margin: 0px;
+  padding-left: 10%;
+}
+
+#message
+{
+  background-color: darkgreen;
+  color: white;
+  margin: 0px;
+  padding-left: 10%;
+}
diff --git a/resources/public/index.html b/resources/public/index.html
index 8b1c5dd..d70e493 100644
--- a/resources/public/index.html
+++ b/resources/public/index.html
@@ -18,9 +18,9 @@ crossorigin=""/ -->
     <h4>
       An ultra-lightweight tool to show comma-separated value data on a map
     </h4>
+    <p id="message"></p>
+    <p id="error"></p>
     <div id="app">
-      <p id="message"></p>
-      <p id="error"></p>
       <div id="map" style="height: 600px; width: 80%; border: thin solid gray;"></div>
       <div id="doc">
         <p>
diff --git a/src/geocsv_lite/core.cljs b/src/geocsv_lite/core.cljs
index f9bea4c..b6b7197 100644
--- a/src/geocsv_lite/core.cljs
+++ b/src/geocsv_lite/core.cljs
@@ -4,14 +4,15 @@
       [clojure.string :as cs]
       [geocsv-lite.data :refer [get-csv-url get-data get-query-part-as-map]]
       [geocsv-lite.gis :as gis]
-      [geocsv-lite.map :as m]))
+      [geocsv-lite.map :as m]
+      [geocsv-lite.notify :as n]))
 
 
 (defn ^:export initialise-map-element
   "Create a map view in the element with this `id` and decorate it with
   pins showing locations from this `data-source`."
   [id data-source]
-  (js/console.log (str "geocsv-lite.core.initialise-map-element called with args id: " id "; data-source: " data-source "."))
+  (n/message (str "geocsv-lite.core.initialise-map-element called with args id: " id "; data-source: " data-source "."))
   (let [sid (str id)
         kid (keyword sid)
         v (m/add-view sid 55 -4 10)]
diff --git a/src/geocsv_lite/data.cljs b/src/geocsv_lite/data.cljs
index 0a47210..c768db1 100644
--- a/src/geocsv_lite/data.cljs
+++ b/src/geocsv_lite/data.cljs
@@ -6,8 +6,7 @@
             [cljs.core.async :refer [<!]]
             [geocsv-lite.gis :as gis]
             [geocsv-lite.map :refer [get-view]]
-            ))
-
+            [geocsv-lite.notify :as n]))
 
 
 
@@ -69,7 +68,7 @@
                     (rest data))
           ]
       (gis/refresh-map-pins (get-view k) records))
-    (js/console.error (str "Bad response from server: " (:status response)))))
+    (n/error (str "Bad response from server: " (:status response)))))
 
 
 (defn get-data
@@ -90,8 +89,3 @@
   (go (let [response (<! (http/get uri))]
           (apply handler-fn (list response k)))))
 
-
-;; (go (let [uri "http://localhost:3449/data/data.csv"
-;;           response (<! (http/get uri))]
-;;       (when (= (:status response) 200)
-;;         (default-handler response :map))))
diff --git a/src/geocsv_lite/gis.cljs b/src/geocsv_lite/gis.cljs
index ca3545f..a9e2a19 100644
--- a/src/geocsv_lite/gis.cljs
+++ b/src/geocsv_lite/gis.cljs
@@ -2,7 +2,8 @@
       :author "Simon Brooke"}
   geocsv-lite.gis
   (:require [cljs.reader :refer [read-string]]
-            [clojure.string :as cs]))
+            [clojure.string :as cs]
+            [geocsv-lite.notify :as n]))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;
@@ -39,28 +40,28 @@
         (fn [position]
           (let [lat (.-latitude (.-coords position))
                 lng (.-longitude (.-coords position))]
-            (js/console.log (str "Current location is: " lat ", " lng))
+            (n/message (str "Current location is: " lat ", " lng))
             (if
               (and view (float? lat) (float? lng))
               (do
                 (.panTo view (.latLng js/L lat lng)))
               (do
-                (js/console.log
+                (n/message
                   (if view
                     (str "Geolocation failed lat: '" lat "'; lng '" lng "'")
                     "No value for subscription to [:view]"))
                 0)))))
       (do
-        (js/console.log "Geolocation not available")
+        (n/message "Geolocation not available")
         0))
     (catch js/Object any
-      (js/console.log "Exception while trying to access location: " + any)
+      (n/error (str "Exception while trying to access location: " any))
       0)))
 
 
 (defn map-pin-click-handler
   [id]
-  (js/console.log (str "Click handler for record #" id)))
+  (n/message (str "Click handler for record #" id)))
 
 
 (defn pin-image
@@ -139,7 +140,7 @@
                                       :title (:name record)}))]
         (.bindPopup marker (popup-table-content record))
         (.addTo marker view)
-        (js/console.log (str "Added `"(:name record)"` in at " lat ", " lng))
+        (n/message (str "Added `"(:name record)"` in at " lat ", " lng))
         marker))))
 
 (defn map-remove-pins
@@ -170,10 +171,12 @@
   centre of the locations of these records as indicated by the values of their
   `:latitude` and `:longitude` keys."
   [records]
-  (let [lats (map js/Number (map :latitude records))
+  (let [lats (remove zero?
+                     (filter number? (map js/Number (map :latitude records))))
         min-lat (apply min lats)
         max-lat (apply max lats)
-        lngs (filter js/Number (map :longitude records))
+        lngs (remove zero?
+                     (filter number? (map js/Number (map :longitude records))))
         min-lng (apply min lngs)
         max-lng (apply max lngs)]
     (if-not
@@ -189,15 +192,16 @@
   [view records]
   (let [view (map-remove-pins view)
         centre (compute-centre records)]
-    (js/console.log (str "refresh-map-pins called; " (count records) " records, centre at " centre))
-    (js/console.log (str "Type of longitude " (:longitude (first records)) " is: " (type (:longitude (first records)))))
     (if
       view
-      (let [added (remove nil? (map #(add-map-pin %1 %2 view) records (range)))]
-        (js/console.log (str "Adding " (count added) " pins"))
+      (do
+        (n/message
+          (str
+            "Mapped "
+            (count
+              (remove nil? (map #(add-map-pin %1 %2 view) records (range))))
+            " records, centre at " centre))
         (if
           (:latitude centre)
-          (do
-            (js/console.log (str "computed centre: " centre))
-            (.setView view (clj->js [(:latitude centre) (:longitude centre)]) (:zoom centre)))))
-      (do (js/console.log "View is not yet ready")))))
+          (.setView view (clj->js [(:latitude centre) (:longitude centre)]) (:zoom centre))))
+      (do (n/error "View is not yet ready")))))
diff --git a/src/geocsv_lite/map.cljs b/src/geocsv_lite/map.cljs
index f56698c..3700a85 100644
--- a/src/geocsv_lite/map.cljs
+++ b/src/geocsv_lite/map.cljs
@@ -1,5 +1,5 @@
 (ns geocsv-lite.map
-    (:require ))
+    (:require [geocsv-lite.notify :as n]))
 
 ;;; Cribbed heavily from
 ;;;   https://github.com/reagent-project/reagent-cookbook/tree/master/recipes/leaflet
@@ -76,15 +76,15 @@
         v (or
             (@views k)
             (map-did-mount id lat lng zoom))]
-    (js/console.log (str "Added Leaflet view to element with id `" id "`"))
+    (n/message (str "Added Leaflet view to element with id `" id "`"))
     (swap! views assoc k v)
     v))
 
 
 (defn get-view
   [k]
-  (when-not (keyword? k) (js/console.log "Key `" k "` passed to get-view is not a keyword"))
-  (when-not (k @views) (js/console.log "Key `" k "` does not identify a known view"))
+  (when-not (keyword? k) (n/message (str "Key `" k "` passed to get-view is not a keyword")))
+  (when-not (k @views) (n/message (str "Key `" k "` does not identify a known view")))
   (k @views))
 
 
diff --git a/src/geocsv_lite/notify.cljs b/src/geocsv_lite/notify.cljs
new file mode 100644
index 0000000..63b2f8a
--- /dev/null
+++ b/src/geocsv_lite/notify.cljs
@@ -0,0 +1,13 @@
+(ns geocsv-lite.notify
+    (:require [clojure.browser.dom :as dom]))
+
+(defn message
+  [msg]
+  (js/console.log msg)
+  (dom/set-text  (.getElementById js/document "message") msg))
+
+
+(defn error
+  [err]
+  (js/console.error err)
+  (dom/set-text  (.getElementById js/document "error") err))