Preparing the Data
==================

|pic1| |pic2|

|pic3| |pic4|

.. |pic1| image:: _static/chap2/B_Level.jpg
   :width: 45%

.. |pic2| image:: _static/chap2/C_Level.jpg
   :width: 45%

.. |pic3| image:: _static/chap2/D_Level.jpg
   :width: 45%

.. |pic4| image:: _static/chap2/E_Level.png
   :width: 45%


Georeferencing
~~~~~~~~~~~~~~

Floor plan images were georeferenced so that shape files for blocks, route and
points can be created. For this purpose, gdal_translate_ command was used

.. _gdal_translate: https://gdal.org/programs/gdal_translate.html

.. code-block:: console
   
   gdal_translate -of GTiff -a_ullr 0 90 180 0 -a_srs EPSG:4326 x_Level.jpg x_Level.tiff



Creating Shape Files
~~~~~~~~~~~~~~~~~~~~

**Polygons**

Georeferenced tiff images were loaded into ArcGIS and blocks (Polygons) were 
created for each rooms.

**Lines**

Line (route) network is created for the whole plan.

**Points**

Using ArcGIS's snapping tool, points for each block (polygon) were placed on
the line network created. These points can be thought of as NODES.



Converting Shape files to EDGES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Using ArcGIS's `Feature to Line tool`__ separate edges were created.
Basic elements for routing (nodes and edges) were prepared now.

__ http://desktop.arcgis.com/en/arcmap/10.3/tools/data-management-toolbox/feature-to-line.htm



Attribute tables
~~~~~~~~~~~~~~~~

.. figure:: _static/chap2/attr_table_blocks.png
   
   Table schema for Blocks shapefile


.. figure:: _static/chap2/attr_table_places.png
   
   Table schema for Places shapefile

Corresponding description are filled in their own columns in blocks and places
shapefiles. Both shapefiles have one attribute in common which is **PlaceNode**.
For every block, there should be a point in the network with same PlaceNodes.
This is useful when a <keyword> is given for searching, its corresponding 
point can be found with the help of this PlaceNode attribute and the network
can be queried for the route.