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Overview

Artifact ID: 532766623da88ae9b3841cfd01d7c2ac8ea6952d
Page Name:LibreAtlasDoc
Date: 2012-06-18 12:59:11
Original User: sandro
Parent: 600c1e29ff91da044e755bbcfab781de71b55e37
Content

A few simple things that will help you get the most from LibreAtlas

LibreAtlas is a simple application mainly intended for teaching and learning about Geography.
Think of the LibreAtlas application as a player/viewer of geography information. That information needs to be provided in the form of a LibreAtlas database. Don't be worried, there is absolutely nothing complex in this. A LibreAtlas database is just a file that you place somewhere on your hard disk, then open with LibreAtlas.

So to get started, you simply:

More about the LibreAtlas databases

You can find any relevant information on the specific Wiki pages: WorldAtlas, ItalyRailAtlas, PiemonteAtlas and LunarAtlas

A very quick how-to tutorial

Menu and toolbar
main-menu.png tool-bar.png
  • you can use the menu or toolbar (or some of each).
    all tools / commands are available on both in the same order, and will have exactly the same effect.

  • group: database connection tools
    You are simply required to use the connect tool in order to establish a permanent connection to some LibreAtlas database.
    Power users may use these tools in order to switch between different Atlases.

  • group: current map selection tools
    These tools are intended to swiftly switch from one map to the other.
    Any current map setting (position, scale) will be preserved untouched.

  • group: map navigation tools
    These tools support map navigation actions (zoom, pan, identify, distance ...).
A third option exists: you can use a popup menu (aka contenxt menu).
You simply have to to click the mouse's right button somewhere over the map, and the popup menu will immediately appear.
context-menu.png

Zooming and panning
  • when the ZoomIn tool is selected, performing a mouse click (left button) on the map area causes a zoom-in action.
    i.e. the map will then be shown at an enlarged reproduction ratio (same screen area represents a smaller area of the world).
    The geographic point corresponding to the mouse click will be placed on the screen centre.
  • when the ZoomOut tool is selected, performing a mouse click (left button) on the map area causes a zoom-out action.
    i.e. the map will then be shown at a reduced reproduction ratio (bigger numeric scale).
    The geographic point corresponding to the mouse click will be placed on the screen centre.
  • Please note: you can always zoom the map using a different approach, i.e. by scrolling the mouse wheel.
    this mechanism is completely independent of the current ZoomIn / ZoomOut state.
  • when the Pan tool is selected, you can drag the map on a new viewpoint.
    i.e. you are required to click the mouse left button, then moving the mouse still holding the left button pressed down.
    the currently shown map will then be glued to the mouse, following its motion.
    once you have reached the appropriate position, you'll simply have to release the mouse left button in order to get the map fully redrawn in the new viewpoint position.
    the scale will always remain unaffected during panning.

On-the-fly identify
While moving the mouse on the map, if some relevant geographic feature is detected at the corresponding coordinates, a small tip will appear; and the intercepted feature will be evidenced on the map.
Example #1
maritime areas on-the-fly detection
i.e. seas, oceans, gulfs and alike
on-the-fly-sea.png
Example #2
land areas on-the-fly detection
i.e. mountain ranges, plains and alike
on-the-fly-range.png
Example #3
hydrography on-the-fly detection
i.e. rivers, lakes and lagoons
on-the-fly-river.png
Example #4
Country on-the-fly detection
on-the-fly-country.png
Example #5
Town on-the-fly detection
on-the-fly-town.png

Country Identify
When the Identify tool is selected, performing a mouse click (left button) on some land map area will cause Country identification.
i.e. a small dialog box will appear, reporting several general infos about the intercepted Country, this including the National Flags and the National Emblem / State Seal.
identify.png

Graticule
When the Graticule tool is selected, Meridians and Parallels will be shown over the map.
And On-the-fly identify will be applied all times that a Meridian or Parallel is intercepted.
graticule.png

Measuring Distances
When the Distance tool is selected, you can measure the distance between two points on the Earth's surface.
Each mouse click (left button) will select a point.
Each time that a pair of points is selected, the corresponding distance will be shown on a dialog box, and the geodesic path will be shown over the map.
great-circle-1.png
Please note: Planet Earth is a sphere (not exactly, it's a geoid, quite approximating an ellipsoid).
So minimum length paths does actually follow Great Circle aka Geodetic lines.
great-circle-2.png
So please don't be surprised if geodetic lines do not look at all like straight lines. great-circle-3.png

That's all ... have a good time and amuse yourself discovering how much fun Geography could be !