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Introduction

To aid in the exploitation of facilities such as Google maps for epidemiological purposes we provide map creation tools allowing you to enter your own data and create a permanent map (which can be bookmarked or sent to others via email).  

Many will be unfamiliar or not have access to latitude / longitude values for the points to be plotted on a map.  We therefore provide two interfaces to geocoding facilities thatallow you to find map co-ordinates. 

Each point on the map is represented by a set of data which, at its most basic, includes the name given to the point, the latitude and longitude values that define the point geographically and a description of the point that appears in a ‘pop-up’ window when the map icon is clicked on.

To produce a map, data are pasted into the map creation pages in TAB delimited format.  It is important to have the data in the correct format and to simplify this procedure we provide excel templates for entering and storing your data.

We demonstrate the use of the tools with some test data

  • 1) Geocoding
  • 2) Simple map creation
  • 3) Advanced map creation

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1) Geocoding

Definition: The activity of defining the position of geographical objects relative to a standard reference grid.
 

Should you be unfamiliar with latitude / longitudes that are needed to build the map, we provide geocoding webpages that take advantage of Googles Geocoding Web Service.  You can geocode by eye using the Map lat/lon lookup  or paste in lists of addresses and have the latitude and longitude (and associated spatial resolution) returned enabling you to build up data to enter into the map creation tools.

 
  • Map Lat/Lon lookup

    Initially you are presented with a zoomed out view of the world.  By clicking/dragging and zooming in you can find the location you wish to Geocode.  By clicking on the map an icon appears and the latitude / longitude is displayed in the pop-up window.   For convenience, below the map the latitude and longitude are also displayed in text boxes which means that you can copy and paste elsewhere.   There is also a link to multimap.com with the point that you have geocoded so you can double check that your point is correct.

     
  • Batch Geocode addresses.

    This facility allows you to paste multiple addresses into a form, each one is then looked up using Googles geocoding facility and the resulting latitude / longitude (if found) are returned.

    You can paste addresses in comma or tab delimited formats
    For example  New York,USA  or New York USA
    The geocoder works at many levels of resolution from street address or postal code (UK) or Zip (US)

    e.g    “10 Downing Street, London” or “The Thite House, Washington DC, USA

    up to country level

    e.g.  Brazil.   

    For countries, capital cities or districts, the centroid point for that region is returned.

    The results returned from the geocoder consist of six columns  as follows : -

    Address | Latitude | Longitude | Accuracy | Number of Addresses Returned | Address or error code.

    As an example,  by entering “London,UK”  the following results are returned –

    london,uk         51.500152       -0.126236        4          1          London, Greater London, UK

    The first column is the ‘Address’ that you typed in.
    The second column is the latitude
    The third column is the longitude
    The fourth column is the Accuracy.

    Accuracy is an integer returned from Google as follows –

    Value Description
    0 Unknown location.
    1 Country level accuracy.
    2 Region (state, province, prefecture, etc.) level accuracy.
    3 Sub-region (county, municipality, etc.) level accuracy.
    4 Town (city, village) level accuracy.
    5 Post code (zip code) level accuracy.
    6 Street level accuracy.
    7 Intersection level accuracy.
    8 Address level accuracy.

    For further details please see here – (http://googlemapsapi.blogspot.com/2006/07/speed-improvements-custom-cursors.html)

    In our example the accuracy is “4”.  This signifies that the geocoding is accurate to the Town (City, Village) level which would be expected for London.

    The fifth column contains the Number of addresses returned.  

    This is "1" for London, UK  because there is only one matching location for London in the UK.

    If however we geocode London,USA  more results are returned as follows- 

    london,usa        37.125766       -84.07986      4          8          London, KY, USA
    london,usa        39.895163       -83.440461     4          8          London, OH, USA
    london,usa        35.330799       -93.247163     4          8          London, AR, USA
    london,usa        47.20278        -91.56944      4          8          London, MN, USA
    london,usa        40.445          -95.23472      4          8          London, MO, USA
    london,usa        37.119612       -84.089603     4          8          London, KY, USA
    london,usa        36.488426       -119.448791    4          8          London, CA, USA
    london,usa        39.890448       -83.434486     4          8          London, OH, USA

    this shows there are 8 (as in the fifth column) matches to London,USA
    .
    In this circumstance it is important to check which address is the one you are interested in using.

    The final column contains the address as stored by Google, which may be more descriptive than the address you entered.

    Points to note –
    If a result is not returned for your address it may be that it is not possible to geocode or it may be that you need to format the query address better.  It is best to include as much information as possible.

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    2) Simple Map Creation

    The simple map tool allows you to plot a list of geocoded locations on a map that you can save as a permanent URL (webpage).

    Any number of points can be plotted and the map and example data should give you some indication of the kind of simple map that can be produced. 

     


    First, enter a title - this will be displayed on the resulting map

    excel
    Data is accepted in TAB DELIMITED format consisting of 4 columns and we provide an EXCEL template to make creating your data easier.
    Data stored in Excel can be copy and pasted directly into the webpage.

    The four columns you must include are as follows -

    name
    latitude
    longitude
    description 

    Name represents the name you have given to your point e.g., a hospital
    latitude is the latitude of the point
    longitude is the longitude of the point
    description is the description you wish to give the data point on the map.

     
      Clicking submit generates a URL to your map. This URL is permanently stored on our servers meaning you can bookmark the link or send to colleagues by email.

    The map is automatically zoomed into a bounding box that shows your data points in as great a detail as possible allowing maps to be produced from a very small scale (e.g. based around a single patch of parkland) up to fully global maps.
    popup
    On viewing the map the Title appears at the top of the page and white icons are present on the map based on the latitude and longitude values you entered.
    Clicking any of the placemarks, an "info window" that pops up containing the description of your Data
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    2) Advanced Map Creation

    The Advanced map tool allows you to group your data into meaningful categories and colour the placemarks of each group differently. This could be applied for example to population figures, presence or severity of a disease etc.

    PLEASE NOTE: we will shortly be making available a much improved version of the Advanced map tool that allows user defined keys and grouping of more than one set of data at a single datapoint (for further info please contact us).

    Any number of points can be plotted and the map and the example data provided should give you some indication of the kind of map that can be produced. 

      As with the simple map tool firstly enter a title for your map
    bulk Data is accepted in TAB DELIMITED format consisting of FIVE columns and we again provide an EXCEL template to make creating your data easier.
    Data stored in Excel can becopy and pasted directly into the webpage.

    The FIVE columns you must include are as follows -

    name
    latitude
    longitude
    description 
    ICON

    Name represents the name you have given to your point e.g a hospital
    latitude is the latitude of the point
    longitude is the longitude of the point
    description is any description you wish to give to the data point.
    ICON represents the choice of ICON for that point based on the KEY given.

    The choice of icon can be used to group your data into defined categories (e.g. they could be ranges (<1%, 1-5%, 6-10% etc) that show the prevalance of drug-resistant malaria parasites).

      As as an example some data to be entered may look as follows -

    Gaborone -24.657 25.9089 capital of Botswana 1
    Ouagadougou 12.3569 -1.5352 Capital of Burkina Faso 1
    Bujumbura -3.3818 29.36223 Capital of Burundi 1
    Yaounde 3.8612 11.5217 Capital of Cameroon 2
    Praia 14.9195 -23.5153 Capital of Cape Verde 10
       
      Clicking submit generates a URL to your map. This URL is again permanently stored on our servers meaning you can bookmark the link or send to colleagues by email.
     
    Each of the groupings you have specified will be shown on the map as the differently coloured icons chosen.

    The map is automatically zoomed into a bounding box that shows your data points in as great a detail as possible allowing maps to be produced from a very small scale (e.g. based around a single patch of parkland) up to fully global maps.
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