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Help Page

Table of Contents

Getting Started
The Map Panel
Map Tools
The Layer List
Selecting An Area of Interest
The Legend
Relevant Terms


Getting Starting

The first step is to choose an administrative boundary (a county, air basin or air district) of interest to you. The main web page returns with additional choices and a map panel that shows the selected area of interest highlighted in yellow, and any power plants in the area.

Once you are inside the main web page you may change your area of interest at any time using the menu found at the bottom of the page (see "Selecting A New County/Air Basin/Air District").




The Map Panel

The Map Panel is where the map image is displayed. The map is a "clickable" image, making it an interactive element of the map page. Using the Map Tools you can zoom in and out on the map, pan around the map, or retrieve information about map features.

The information displayed on the map is dependent on:

  • Which layers are "turned on" in the layer list and
  • the scale at which you are zoomed to.
  • As you zoom in on the map you will reveal more detail in the form of additional data. This is due to the presence of scale-dependent map layers. Often map layers that show a great amount of detail have pre-set scales at which they become visible. This is to prevent this data from obscuring the map at small scales. Use the zoom in tool to increase the scale of the map until these layers are visible.

    The map scale is displayed with a scale bar at the bottom left-hand corner of the map.

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    Map Tools

    The Map Tools perform a variety of functions, from navigation, to printing the map.

    Some Map tools, namely the Zoom tools, Pan tool, and Information tool, require interaction with the map panel following their selection. To select one of these tools click once on the tool icon. You will notice that a red box appears around the icon to indicate that it is the currently selected tool.

    The remaining map tools, the Zoom In/Out 20% buttons, Full Extent button, and the Print button do not require interaction with the map, only a single click on the tool icon.

    Zoom In
     

    The magnifying glass with the plus sign is used to zoom in on a specific point on the map. To use the tool, select the zoom in icon from the tool bar, select a zoom factor from the drop-down menu located below the map panel, then click on the map. The point on which you click becomes the center of magnification, and, subsequently, the center of the new map. By default, each click on the map with the zoom in tool increases the map scale by 50 percent (2x). You can control how much the scale increases by adjusting the zoom factor appropriately prior to using the zoom in tool.

     
     

    As you zoom in on the map you will reveal more detail in the form of additional data. This is due to the presence of 'scale-dependent' map layers. Often map layers that show a great amount of detail have pre-set scales at which they become visible. This is to prevent this data from obscuring the map at small scales.


    Zoom Out
     

    The magnifying glass with the minus sign is used to zoom out from a specific point on the map. To use the tool, select the zoom out icon from the map tool panel, select a zoom factor from the drop-down menu located below the map panel, then click the map. The point on which you click becomes the center of magnification, and, subsequently, the center of the new map. By default, each click on the map with the zoom out tool decreases the map scale by 50 percent. You can control how much the scale increases by adjusting the zoom factor appropriately prior to using the zoom out tool.

       
     

    As you zoom out, the map will display less detail as 'scale-dependent' layers turn off (see the Zoom In tool description for a more detailed discussion of scale-dependent layers).


    Zoom In 20%
      The 'Zoom In 20%' tool allows you to zoom in on the map in small, controlled increments. Click this button once to increase the map scale by 20 per cent. This tool does not require a map click.

    Zoom Out 20%
      The 'Zoom Out 20%' tool allows you to zoom out from the map in small, controlled increments. Click this button once to decrease the map scale by 20 per cent. This tool does not require a map click.

    Pan
      The hand is the pan tool. Panning is a useful function that allows you to move around the map without changing the scale. Think of it as shifting a paper map across a desktop in order to view a different portion of it. To use the pan tool select the pan icon from the map tool panel and then click once on the map. The new map image will be centered around the point of your map-click.

    Full Extent
      The full extent tool allows you to quickly zoom out to the map's maximum extent. To use the full extent function, simply click on the full extent icon. The full map area will be displayed in the map panel.

    Information
     

    The stylized "i" icon is the Information tool. This tool allows you to retrieve information about California's Power Plants.

    Click on any Power Plant with the Information tool to retrieve the following information:

  • Plant Name
  • Primary Fuel Used
  • Technology Used
  • Online Power (Mega Watts)
  • Gross Power (Mega Watts)
  • Max. Power (Mege Watts)
  • Online Since Date
  • Operator/Owner


  • To use the tool, select the Information tool from the toolbar, then position your cursor on top of the power plant(s) you are interested in and click with the left mouse button. If a plant is found at the location of your map click then the results are returned in a seperate window, in a format similar to that shown below:


    Print
      The print tool generates a print preview page that you can send to your local printer.

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    The Layer List

    The map displayed on this web site is composed of a number of stacked data "layers". A layer can be thought of as a collection of features with a common theme. For example, all of the State of California's major highways are contained on a single layer, as are the state's cities, major water bodies and so on.

    A list of the map layers (shown on the right) is located to the right of the map panel. Each layer has an associated "check box" which indicates the layer's visibility - layers with a checkmark are currently visible on the map. Check boxes can also be used to turn a layer's visibility on or off . To check, or un-check a box, simply click the box with your mouse pointer. To submit changes you have made to layer visibility click the "Refresh The Map" button found beneath the list. This functionality gives you the ability to customize the appearance of the map, displaying only the layers you want to see.

    At times the layer list will include layer names that have been "grayed-out". This indicates that the layer's visibility is controlled by scale-dependency. If a layer name has been grayed-out it means that you have either zoomed in beyond the layer's minimum scale threshold or you have zoomed out beyond the layer's maximum scale threshold. When the map scale returns to within the layer's upper and lower scale thresholds the layer name will no longer be grayed-out, and you will be able to control it's visibility via a check-box.

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    Selecting An Area of Interest
    At the bottom of the web page you will find a drop-down menu containing a list of all 58 counties in the state of California, as well as the state's 15 recognized Air Basins, and 35 Air Districts. Each category is indicated by a heading.
     
    This menu allows you to quickly zoom to an area of interest to you. Selecting a county, air basin, or air district from the list automatically redraws the map to your chosen extent and highlights the boundaries of your area of interest.

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    The Legend
    To view a legend for the visible map layers click the "View The Legend" button, found to the right of the map. This spawns a new browser window containing the legend (pictured on right).

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    Relevant Terms
    This section provides definitions of some of the terms used in this application.

    Air Basins

    California is divided geographically into air basins for the purpose of managing the air resources of the State on a regional basis. Areas within each air basin are considered to share the same air masses and are therefore expected to have similar ambient air quality. The State is currently divided into 14 air basins.

    Air Districts

    The State is divided into Air Pollution Control Districts and Air Quality Management Districts, which are also called air districts. These agencies are county or regional governing authorities that have primary responsibility for controlling air pollution from stationary sources 

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