diff --git a/.gitignore b/.gitignore
index cc7c57e..b062fcb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,3 +14,5 @@ pom.xml
 .nrepl-port
 
 resources/public/data/
+
+.rebel_readline_history
diff --git a/resources/public/css/style.css b/resources/public/css/style.css
index 26163d2..36af86f 100644
--- a/resources/public/css/style.css
+++ b/resources/public/css/style.css
@@ -1,2 +1,46 @@
 /* some style */
 
+body {
+  font-family: Helvetica, Ariel, sans-serif;
+  padding-bottom: 4em;
+}
+
+div#app {
+  margin-left: 10%;
+}
+
+footer {
+  clear: both;
+  font-size: smaller;
+  text-align: center;
+  color:white;
+  background-color: #3298dc;
+  width: 100%;
+  margin: 0;
+  padding: 0.25em 0;
+  bottom:0;
+  position:fixed;
+  vertical-align: top;
+  z-index:150;
+  _position:absolute;
+  _top:expression(eval(document.documentElement.scrollTop+
+        (document.documentElement.clientHeight-this.offsetHeight)));
+}
+
+footer a {
+  color: #ddd;
+}
+
+
+h1 {
+  width: 100%;
+  margin: 0;
+  padding-left: 10%;
+  text-align: left;
+  background-color: #3298dc;
+  color: white;
+}
+
+samp {
+  background-color: #b0b0ff;
+}
diff --git a/resources/public/favicon.ico b/resources/public/favicon.ico
new file mode 100644
index 0000000..de48631
Binary files /dev/null and b/resources/public/favicon.ico differ
diff --git a/resources/public/index.html b/resources/public/index.html
index b2a28a7..dda957e 100644
--- a/resources/public/index.html
+++ b/resources/public/index.html
@@ -1,10 +1,11 @@
 <!DOCTYPE html>
 <html>
   <head>
+    <title>GeoCSV Lite</title>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <link href="css/style.css" rel="stylesheet" type="text/css">
-    <link rel="icon" href="https://clojurescript.org/images/cljs-logo-icon-32.png">
+    <link rel="icon" href="favicon.ico">
     <!-- if you prefer loading libraries from standard hosts, un comment this and
       comment out the local source -->
     <!-- link rel="stylesheet" href="https://unpkg.com/leaflet@1.6.0/dist/leaflet.css"
@@ -13,11 +14,50 @@
     <link rel="stylesheet" href="vendor/node_modules/leaflet/dist/leaflet.css" type="text/css">
   </head>
   <body>
+    <h1>GeoCSV Lite</h1>
     <div id="app">
-      <h2>Figwheel template</h2>
-      <p id="message">Checkout your developer console.</p>
-      <div id="map" style="height: 600px; width: 80%; margin-left: 10%; border: thin solid gray;"></div>
+      <p id="message"></p>
+      <p id="error"></p>
+    <div id="map" style="height: 600px; width: 80%; border: thin solid gray;"></div>
     </div>
+      <div id="doc">
+        <p>
+          Use this page as a crib for how to use <b>GeoCSV Lite</b> in your projects. In order
+          for it to work, you need:
+        <ol>
+          <li>Javascript dependencies:
+            <ol>
+              <li><a href="">Leaflet</a> (provides mapping);</li>
+              <li><a href="">PapaParse</a> (provides CSV parsing);</li>
+            </ol>
+          </li>
+          <li>
+            A line which includes the geocsv_lite library, which should be
+            <em>after</em> those including the dependencies: <br/>
+            <samp>&lt;script src="js/compiled/geocsv_lite.js"
+              type="text/javascript"&gt;&lt;/script&gt;</samp>
+          </li>
+          <li>One (or more) <code>div</code> elements to contain your maps. It
+            is a requirement of Leaflet that these must have a fixed pixel width.
+            Each must have a distinct <code>id</code>;</li>
+          <li>
+            For each <code>div</code> which you wish to contain a map view,
+            an invocation of the function
+            <code>geocsv_lite.core.initialise_map_element(id, data-source)</code>: <br/>
+            <samp>&lt;script&gt;geocsv_lite.core.initialise_map_element("map", "/data/data.csv");&lt;/script&gt;</samp>
+          </li>
+        </ol>
+        </p>
+    </div>
+    <footer>
+      <div id="credits">
+        <div>
+          <img height="16" width="16" alt="Clojure" src="img/credits/clojure-icon.gif"/> Powered by <a href="http://clojure.org">Clojure</a> ||
+          <img height="16" width="16" alt="GitHub" src="img/credits/github-logo-transparent.png"/>Find me/fork me on <a href="https://github.com/simon-brooke/geocsv-lite">Github</a> ||
+          <img height="16" width="16" alt="Free Software Foundation" src="img/credits/gnu.small.png"/>Licensed under the <a href="http://www.gnu.org/licenses/gpl-2.0.html">GNU General Public License version 2.0</a>
+        </div>
+      </div>
+    </footer>
     <!-- if you prefer loading libraries from standard hosts, un comment this and
       comment out the local source -->
     <!-- script src="https://unpkg.com/leaflet@1.6.0/dist/leaflet.js"
@@ -27,5 +67,8 @@
     <script src="vendor/node_modules/leaflet/dist/leaflet.js"></script>
     <script src="vendor/node_modules/papaparse/papaparse.min.js"></script>
     <script src="js/compiled/geocsv_lite.js" type="text/javascript"></script>
+    <script>
+      geocsv_lite.core.initialise_map_element("map", "/data/data.csv");
+    </script>
   </body>
 </html>
diff --git a/src/geocsv_lite/core.cljs b/src/geocsv_lite/core.cljs
index a2006e1..f9bea4c 100644
--- a/src/geocsv_lite/core.cljs
+++ b/src/geocsv_lite/core.cljs
@@ -6,14 +6,16 @@
       [geocsv-lite.gis :as gis]
       [geocsv-lite.map :as m]))
 
-(enable-console-print!)
 
-(println "This text is printed from src/geocsv-lite/core.cljs. Go ahead and edit it and see reloading in action.")
-
-
-
-
-;; define your app data so that it doesn't get over-written on reload
+(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 "."))
+  (let [sid (str id)
+        kid (keyword sid)
+        v (m/add-view sid 55 -4 10)]
+    (.whenReady v (fn [] (get-data kid data-source)))))
 
 (defonce app-state (atom {:text "Hello world!"}))
 
@@ -21,11 +23,4 @@
   ;; optionally touch your app-state to force rerendering depending on
   ;; your application
   ;; (swap! app-state update-in [:__figwheel_counter] inc)
-  (m/add-view "map" 55 -4 10)
-  (let [query (get-query-part-as-map)
-        uri (get-csv-url query)
-        records (get-data :map)]
-    (dom/set-text (.getElementById js/document "message")
-                  (str "Query was: " query "; uri was: " uri))))
-
-
+)
diff --git a/src/geocsv_lite/data.cljs b/src/geocsv_lite/data.cljs
index e5277a9..0a47210 100644
--- a/src/geocsv_lite/data.cljs
+++ b/src/geocsv_lite/data.cljs
@@ -8,20 +8,12 @@
             [geocsv-lite.map :refer [get-view]]
             ))
 
-;; function getQueryVariable(variable)
-;; {
-;;        var query = window.location.search.substring(1);
-;;        var vars = query.split("&");
-;;        for (var i=0;i<vars.length;i++) {
-;;                var pair = vars[i].split("=");
-;;                if(pair[0] == variable){return pair[1];}
-;;        }
-;;        return(false);
-;; }
+
 
 
 (defn get-query-part-as-map
   "Returns the query part of the current document URL as a keyword-string map."
+  ;; not actually used in the current incarnation
   []
   (let [query-nvs (map #(cs/split % "=") (cs/split (subs js/window.location.search 1) "&"))]
     (when (every? #(= (count %) 2) query-nvs)
@@ -35,6 +27,7 @@
   * `:uri` whose value is the URI of a JSON or CSV file.
 
   If either of these keys is found, returns an appropriate URL, else nil."
+  ;; not actually used in the current incarnation
   [query]
   (when (map? query)
     (cond
@@ -46,35 +39,50 @@
 
 
 (defn default-handler
+  "When data is received from a URL, it is received asynchronously. This
+  is the default callback called with the `response` of the HTTP request,
+  and the keyword `k` identifying the map view, to populate the map with
+  data."
   [response k]
   (if
     (= (:status response) 200)
     (let [content (:body response)
-          data (js->clj (.-data (.parse js/Papa content)))
+          data (map
+                 #(merge %
+                         {:longitude (js/Number (:longitude %))
+                          :latitide (js/Number (:latitude %))})
+                 (js->clj (.-data (.parse js/Papa content (clj->js {:dynamicTyping true})))))
           cols (map
-            #(let [n (cs/lower-case (cs/replace (cs/trim %) #"[^\w\d]+" "-"))]
-               (keyword
-                 (if (empty? n)
-                 (gensym)
-                   n)))
-            (first data))
+                 #(let [n (when-not
+                            (empty? %)
+                            (when (string? %)
+                              (cs/lower-case
+                                (cs/replace
+                                  % #"[^\w\d]+" "-"))))]
+                    (keyword
+                      (if (empty? n)
+                        (gensym)
+                        n)))
+                 (first data))
           records (map
                     (fn [r] (zipmap cols (map str r)))
                     (rest data))
           ]
-      ;; (println records)
       (gis/refresh-map-pins (get-view k) records))
-    (println (str "Bad response from server: " (:status response)))))
+    (js/console.error (str "Bad response from server: " (:status response)))))
 
 
 (defn get-data
-  [k]
+  "Get data for the view identified by this keyword `k` from this `data-source`.
+  In this initial release the data source must be a URL, but in future releases
+  I intend that it may also be a list of maps representing records, or a CSV or
+  JSON formatted string."
+  [k data-source]
   (let
-    [uri (get-csv-url (get-query-part-as-map))]
+    [uri data-source]
     (go (let [response (<! (http/get uri {:with-credentials? "false"
                                           :access-control-allow-credentials "true"
                                           :origin js/window.location.hostname}))]
-          (println (cs/join " " ["tx:" uri "rx:" (:status response)]))
             (default-handler response k)))))
 
 (defn get-data-with-uri-and-handler
@@ -83,7 +91,7 @@
           (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))))
+;; (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 b594740..ca3545f 100644
--- a/src/geocsv_lite/gis.cljs
+++ b/src/geocsv_lite/gis.cljs
@@ -116,8 +116,8 @@
   "Add an appropriate map-pin for this `record` in this map `view`, if it
   has a valid `:latitude` and `:longitude`."
   [record index view]
-  (let [lat (:latitude record)
-        lng (:longitude record)]
+  (let [lat (js/Number (:latitude record))
+        lng (js/Number (:longitude record))]
     (if
       (and
         (number? lat)
@@ -170,10 +170,10 @@
   centre of the locations of these records as indicated by the values of their
   `:latitude` and `:longitude` keys."
   [records]
-  (let [lats (filter number? (map :latitude records))
+  (let [lats (map js/Number (map :latitude records))
         min-lat (apply min lats)
         max-lat (apply max lats)
-        lngs (filter number? (map :longitude records))
+        lngs (filter js/Number (map :longitude records))
         min-lng (apply min lngs)
         max-lng (apply max lngs)]
     (if-not
@@ -185,11 +185,12 @@
 
 (defn refresh-map-pins
   "Refresh the map pins on the current map. Side-effecty; liable to be
-    problematic."
+  problematic."
   [view records]
-  (js/console.log "refresh-map-pins called")
   (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)))]
diff --git a/src/geocsv_lite/map.cljs b/src/geocsv_lite/map.cljs
index 38576d5..f56698c 100644
--- a/src/geocsv_lite/map.cljs
+++ b/src/geocsv_lite/map.cljs
@@ -72,16 +72,20 @@
 
 (defn add-view
   [id lat lng zoom]
-  (let [k (keyword id)]
-    (when-not
-      (@views k)
-      (swap! views assoc k (map-did-mount id lat lng zoom)))
-    (views k)))
+  (let [k (keyword id)
+        v (or
+            (@views k)
+            (map-did-mount id lat lng zoom))]
+    (js/console.log (str "Added Leaflet view to element with id `" id "`"))
+    (swap! views assoc k v)
+    v))
 
 
 (defn get-view
   [k]
-  (@views 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"))
+  (k @views))
 
 
 
