Introduction to HSLayers
########################
`HSLayers <http://redmine.ccss.cz/projects/hslayers>`_ is yet another
`OpenLayers <http://openlayers.org>`_ & `ExtJS <http://extjs.com>`_ based mapping framework. It's development has been
started in 2007 and is still provided mainly by `Help Service - Remote
Sensing <http://bnhelp.cz>`_. HSLayers is released under GNU/GPL.
Currently, 3.0 development branch is the actual.

.. image:: ../_static/hslayers.png

Structure of HSLayers
*********************
There are two main parts of HSLayers: patches and addons. 

Patches
=======
Patches are little improvements to original OpenLayers code. Usually, they
are later accepted by OpenLayers as patches. But before they do, they are
living in the :file:`patches` directory and they are added to final build
of :file:`OpenLayers.js` at the and, and so, the functionality of some
methods or classes is modified little bit.

In actual version, following modifications are added:

* Control
    * ModifyFeature.js
    * Navigation.js
    * OverviewMap.js
    * PanZoom.js
    * PanZoomBar.js
    * Scale.js
    * SelectFeature.js
    * ZoomBox.js
* Format
    * WMC
         * v1.js
* Handler
    * Donuts.js
* Layer
    * Vector
        * RootContainer.js
    * Vector.js
    * WFS.js
* Renderer.js

You see, that most of the modifications are located in
:file:`OpenLayers.Control`.

The patches are little modifications to original OpenLayers code (use
:kbd:`Control` key for zooming instead of :kbd:`Shift`), sometimes, they
are more complex (e.g. introducing polygons with holes while vector
editing).

Addons
======
Here is new stuff or modified features, widgets, layers, controls etc. added to original
code. Among others:

* New map Controls
    * Click
    * ArgParser
    * BoxLayerSwitcher
    * Draw controls
    * LayerSwitcher
    * State 
    * Query
* Layers
    * ChartLayer
    * WarpedWMS
    * MapServer
* OWS
    * WMS client
    * WFS client
* Widgets
    * Map window
    * Printing
    * MapPortal
    * InfoPanel

and  others.

Server-side scripts
===================
Several scripts are available as well, namely 

* warping script for on-the-fly raster data projection
* printing script for creating hard-copy maps

In this workshop, you should be able to *install*, *setup* and *customize*
HSLayers.