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Friday, May 10, 2013

Download LIDAR Data for free

USGS provides users with a series of LIDAR point cloud in the form of tiles.

The Viewer User Instructions give an overview of the map interface page. The overview is a comprehensive list of tools and functionality of all Web Mapping map interfaces. The tools and funtionality are not available on all map interface pages. Depending on the purpose of the page, different tools are available, as well as, initial map region, reference layers, and download capability. In addtion to the Viewer User Instructions, a tutorial (.pdf) has been written for the Seamless Data Distribution System website that can be used a reference tool.

Viewer User Instructions are organized in four sections:

open
1. Tool Bar -- (Left side section)-- The Tool Bar is divided into Six categories:
    A. Move
    B. Zoom
    C. Query
    D. Tools
    E. Download
    F. Docs or Misc

A. Move
Pan OptionsThe move category provides tools to aid in navigating within the map region
The Pan arrows (the grey and pink line with arrows) will move the map in one direction by about 1/2 of the current screen extent. Imagine a window that is shifted/moved in the given direction to show a new view.


B. Zoom
Zoom Categories The zoom category provides tools to aid in navigating within the map region.
    Zoom In
    The Zoom In tool, default, is used to enlarge a portion of the map. Select this tool, then click and draw a box on the map around the area what you wish to see in more detail. Clicking without drawing a box, will zoom in with the center point where you clicked by a factor of 2.
    Zoom to Full Extent
    The Full Extent Zoom tool will zoom out to the starting/initial extent of the map.
    Zoom Out
    The Zoom Out Tool is used to zoom out a portion of the map. The box drawn with this tool is used to calculate a zoom out factor. A smaller box will zoom out more than a large box. Clicking without drawing a box, will zoom out with the center point where you clicked by a factor of 2.
    Zoom to Region
    The Zoom to Region or Area tool allows you to zoom to a region, state, or locale. Click on the tool, below the map region are drop down menus to choose a Region, State, or Locale. Once an area is choosen, the map will automatically zoom to the location.
    Zoom to Previous Extent
    The Zoom to Previous Extent tool will change the extent to the last extent (like an undo feature just for the zoom scale).
    Zoom to Point
    The Zoom to a Point tool allows you to enter a coordinate. Click on the tool and a window will pop up. Enter coordinates, Longitude and Latitude in decimal degrees, then click OK. The map will zoom in and center around the coordinates entered at a scale of approximately 1:3,700,000.
C. Query
Query Categories The Query category provides tool to query information from the map.
    Identify
    The Identify button provides information about a certain point. Click the button, then click on the map. A window will appear with information about the point and the layers.
    Search
    The Find (binoculars) button allows you to locate a certain point. Click the button, then a window will appear to enter a populated place. Click OK. A list of names is diplayed below the map region. Scroll to see the choices. Click on the Goto to have the map zoom to that specific area.
    Elevation Point Query
    The Elevation Point Query button allows you to click a location on the map and an elevation is returned. Click the button, then click anywhere on the map. Below the map region an elevation, in feet, latitude, and longitude are displayed for the specific point. The data source uses the best available elevation data.
    US National Grid Conversion
    The US National Grid Conversion button allows you to click a location on the map and the US National Grid coordinate, Latitude, and Longitude is returned. Click the button, then click anywhere on the map. Below the map region the USNG coordinate, latitude, and longitude are displayed for the specific point.
    Elevation Profile
    The Elevation Profile button allows you to click points on the map and receive a graph with the elevation profile between the points. Click on the button, then click a starting point on the map, then click an ending point. Below the map region, options will appear for generating the profile graph. To generate the graph, click "Generate Profile for 2 Points" Once the information is processed a graph will appear in a new window illustrating a profile between the two selected points.
D. Tools
Tool Categories The Tools category provides the user with different capabilities to apply to the map. Some Tools listed are not available on all map interfaces.
    Pan Map
    Pan Tool (hand icon) is used to drag the map in any direction and recenter the view. Simply click on the Pan Tool, then drag the map to a new location.
    Measure
    Measure Tool allows you to measure distances on the map. Click the tool, then click a point on the map. Then move the mouse and distances are displayed on the top of the map. Click another point and this will draw an line between the two points.
    Eraser
    Eraser Tool allows you to clear any tool that was applied to the map. Click on the button and the map is cleared.
    Print
    Print Icon allows you to create a .pdf file of the area displayed on the screen. Manipulate the map to display the area and layers to be printed. Click the printer icon. A window will appear with options to add a title, adjust the page layout, and the image size. Click "Get Image" to generate a .pdf file. A processing page window will appear. Once completed a .pdf file is created. This file can be saved or printed.
    Metadata
    Metadata Tool allows you display metadata for a specific layer and location. Click on button, a drop down list will be displayed below the map region. Choose a product, then click on the desired layer on the map. FGDC metadata will be displayed.
    Layer Transparency
    Transparency Tool allows you to adjust a layer to be transparent. Click the button, choose a layer and adjust the transparency. Click Apply Transparency button.
E. Download
Download Categories The download category provides tools to download data.
    Select Desired Download
    The Define Tiled Selection button allows you to draw a box on the map over the desired area to download. Click on the button, then using the mouse click and drag a box over the area of interest. Once the mouse is released the download pages will start processing to find pre-existing tiled datasets.
F. Docs or Misc
Document Categories The Docs or Misc category provides links to documents, like metadata, or tools, depending on the map interface. Some map interfaces contain a Misc category and all tools mentioned above, except move and zoom, are included in the category.
    Map Information
    OGC Metadata button lists all of the layers reference layers available. Click on the button and a list will appear.
    Legend
    The Legend button allows the user to display the legends for the map layers. Click the button, then in the Display list the legends will appear. Clear the legend button again and the legends will toggle off.
    Refresh
    Refresh button allows the user to refresh the map interface.
    Instructions
    Viewer User Instructions button displays the help for the map interface page.


2. Map Region -- (Center section) -- This is the location of the actual map to manipulate with the tools.



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3. Display/Layers Information -- (Right side section) -- The Display/Layers Information contains two categories.
    A. Scale Information
    B. Layers
A. Scale Information
    ScaleThe Scale Information category provides a quick mechanism to display the map in or out. Depending on the scale, more layers become available. The scale is displayed for quick reference.


B. Layers
The Layers category provides the list of reference layers and with some map interfaces the download layers list.
Display TabThe Display tab lists the major categories of layers that can be overlayed on the map. Click the twist tie to reveal the reference layers available within the categories. The map will automatically refresh. As an area is zoomed in more layers will become available to add to the map. Some map interfaces do not have a tab, but the list of categories. Then within the categories the reference layers available.

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