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Map based browsing is an alternative mode for the view and selection of Stations. This application has been developed with a purpose that the User views the static data across the Intranet / Internet which acts as a precursor for the dissemination of the data. The GIS interface is one of the links to the catalogue where the Hydrological Data User submits the Data Request File to the database. The user has access to the functionalities that he intends to perform on the spatial data being accessed from the database.
Figure 1: Map of India showing the Administrative and Basin
boundaries with an Inset which will show the status of
navigation.
This is a vector map with a connection to the spatial database. Since the features are picked from the database all updations like addition of new sites to a certain Site type are reflected dynamically, the same holds good for the deletion of sites from a certain category. The Administrator can set a new default map by creating a Map Definition File in the Web Map Administrator menu.
"Making Layers Active and Passive"
The catalogue displays the different Site Types depicted as points in different colors in State and Basin’s. The User can turn on or off the individual layers as well as multiple site types by checking on the checkbox provided along side each site type and clicking on the Display Map button. Each site type is identified with a legend that has been provided alongside the feature class name. Apart from the different site types map layers like Drainage, Metalled Roads, Drainage, Highways have been provided such that the User can view the spatial distribution of layers with respect to the States.
To view the data with respect to a individual state or states the User can click on that particular state (the State boundaries have been hotspotted), a map is generated for the state on which the Hydrological Data User has clicked.
Figure 2: State of Andhra Pradesh hotspotted.
Clicking on a state boundary drills into that particular state.
When the User clicks on the hotspotted state the map drills into that particular state as shown in the
Figure 3. The User can see the district boundaries, drainage, Metalled roads and highways as shown in Figure 4.
Figure 3: State of Andhra Pradesh after clicking on the hotspotted
state with inset showing the state of Andhra
Pradesh.
Figure 4: Map showing the Discharge, Sediment and Other
Site.
Selection and Browse mode
Depending on the Site Types chosen and the mode
- Single - Gives metadata about the site on which the User clicks
- Multiple - Facilitates the User to select the sites on the map. A particular station can be selected on a mouse click and it can be deselected by clicking on the same station
- Invert - Inverts the selection
- Select All - Selects all
stations in the Active layer
To summarize, for selection by point and click the HDU has to go for the multiple option, select the Site Type and then click on the Display Map button. The map features are displayed and then he can begin collecting the points.
Figure 5 - Points Selected
Collected points displayed in window shown by clicking on the sites of interest in the map
window as well as in a new window showing the total number of
sites queried and the number of sites collected.
"Selection by mouse drawn polygon"
Stations can also be selected by selecting groups
of them on the map by a mouse drawn polygon. Features
within a user-defined polygon will be selected and
they will be displayed with a different symbology.
Figure 7 - Confirmation for the drawing of fence for selection
of a chunk of sites.
Figure 8 - Selected sites by mouse drawn polygon shown in a
different symbology.
Toggling: This feature
enables the Hydrological data user to seamlessly
switch between the map based and list based browsing.
The User may select the state of Andhra Pradesh
and Bore wells in the List based selection and then
click on the button Switch to List, the map for
the state and site type selected is displayed .The
User can select some more states and basins for
the site type selected and then click on the Display
Map button. The selected states and basins are displayed,
if the User clicks on the Switch to List link then
the selected states and basins are displayed as
shown in figures.
Figure 9 - showing the state and site type selected.
The User can click on Data Availability button to
see the data available or click on the Switch to
map button to view the spatial distribution of wells.
Figure 10 - Site type selected in the List
based selection.
To select another state in the map, turn on the
Administrative Boundaries map layer. All the Hydrology
Project states are hotspotted to enable selection,
click on the state for which the administrative
boundaries have been demarcated, turn off the Administrative
boundaries layer and then click on the Display Map
button. Since the basin boundaries are displayed
as such the User can select the basin for which
he wants to view the data.
Figure 11 - States and basins selected along with the site types.
Advanced User functions
This functionality facilitates the User to narrow
down his search by using some additional criteria
like "AND / OR" operators, keying
in only latitude or longitude or by keying in both.
By just selecting the Site types and entering the
latitude and longitude all the stations found within
the search criteria are displayed, the User might
not select any state, basin, district, agency. The
User can use the operators depending on his need.
To explain the result expectation if the User uses
the condition AND between a State and a Basin for
example the User searches for Bore Wells in the
state of Andhra Pradesh and Godavari
basin, then the query result would be the stations
common to the state of interest and the basin. The
or condition displays all the
sites present in the state of interest and the basin
Figure 12 - Advanced User interface where in he
employs the operators and searches with respect
to latitude and longitude
Visualize Spatial Distribution of Selected
Stations
The application will provide spatial distribution
of selected stations through customization. Clicking
on the point the latitude and longitude will be
displayed for that particular location. The information
for a particular location can also be displayed
using a tool tip.
Zoom and Pan Functionality
Zoom and Pan functionalities are made available.
The HDU can select the area of interest by using
the zoom and pan buttons.
Printing of Map Layers
The HDU can take print outs of the map window by
right clicking on the map window and choosing the
option Print.
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