Local Authority population map is a map portal which can optionally display
Local Authority and Grama Niladhari Division
administrative area boundary layers as overlays and many other open layers available
such as Google and Open road map layers as base layers. The list of available
Overlays also includes thematic maps of Population, Population density etc.
reported within the respective administrative boundaries during the Census of Population
and Housing 2012.
User guide: How to ...
The following thumbnails explain and display how to get the things done within this map portal
and answers to FAQs.
To display base layers from available open layers select the desired base
layer by selecting the radio button located left to the desired layer. Please note that base
layer loading time depends on the internet speed and only one layer at a time is allowed
to be selected and displayed as the base layer. Selecting Blank as base layer results the overlays display
on a blank screen without any back ground layer.
Some overlays are already on display by default and the layers could be get on and off the display by selecting or
deselecting the tick box located left to every layer. Multiple layers are allowed to display
though the topmost layer according to the order of the list of layers covers the rest of the
layers below it if it displays colors.
Zooming the map could be done using either the vertical zoom slider, tool bar zoom
buttons or using scroll up and scroll down of the mouse for zoom out and zoom in respectively.
Additionally zooming to max, previous and next extents and to layer extent also possible
using the 6 buttons provided at the left corner of the tool bar. When the mouse is used
the center point for zooming would be where the mouse pointer is where as the vertical zoom slider
and zoom buttons zooms in and out around the current center of the map.
For panning the map the 4 panning buttons
located at the top left corner of the map or dragging the map to any direction with clicked
mouse on the map could be used. The 4 panning buttons are useful when exact vertical or horizontal
panning is needed.
To find a place and data related to a certain area the Google search place holder
has been placed at the end of the tool bar.
Just type the name of the place to find in the search place holder and press enter
key to find the place on the Google base layer map with
automated panning the map where needed to center the place searched for in the map.
To read the data of a over lay the Identify button located at the tool bar should be kept pressed.
When the mouse is clicked on the thematic map, the available data related to the place where
clicked is read from the data table of the boundary (or polygon)
or Data layer is displayed in a pop up table. To identify a boundary line and to get
the names of the 2 areas of the map divided by the polygon line displayed in the pop up
table the line or the border of the area should be clicked while the identify button is kept pressed.
In order to avoid boundary layers being covered by the data layers the layer order could
be changed and the desired view could be obtained. For example a lower level boundary could be brought up
by dragging the layer in the layer list and dropping it above any layer or right at
top or bottom of the list after moving up or down. Please note that the base layers are unique and
can not be moved up or down.
Overlays are stored in DCS Geoserver from which different layers could be
brought in to the list of overlays already set up as default layers. To bring new layers in to
display use Add button located at top left hand side corner of the web page
and select a layer from the DCS Geoserver layer pop up menu or any other server
known by double clicking on any layer.
Thematic maps necessarily carry a legend to distinguish and illustrate prevailing differences
between the macro data bounded to and collected at different administration areas.
The Standard deviation of the data set, which could be calculated and applied for any
data set is the best scale to group data in to a common list of categories.
Data set transformed in to a standard normal distribution by distracting each data point value
from the mean and then dividing it by the known and pre-calculated Standard deviation of the
data set itself fits to a common legend as shown above. Mean value of the normalized dataset
is always zero and above 1 and less than -1 values of a normalized data set could generally
be considered as higher and lower extreme values respectively. Normalized data values lie
between -0.5 and 0.5 are closed to the mean or average of the data while the data values ranging
between -1 and -0.5 as well as 0.5 and 1 are neither extreme nor close to the average.
The population and administration area map interactively displays a group of images and
number of layers from which a unique portion is either copied or saved as user wished.
When saving the map in to an image file the selected map tile of the topmost layer or the map
component is downloaded and saves as an image in to user preferred storage location.
The same portion can be copied and pasted on a text or image editor and this allows users
to create their own page arrangement using different image components set at screen selecting
a view from many different zoom levels and thousands of different views which panning the map
brings in to display.
To print and/or save the map exactly as it appears on the screen the print screen option,
which copies the screen image to the memory of the local web-browser machine could be used.