What is Google Earth? How it is work? Which satellite image used it ?
Google Earth is a geobrowser that accesses satellite and aerial imagery, ocean bathymetry, and other geographic data over the internet to represent the Earth as a three-dimensional globe. Geobrowsers are alternatively known as virtual globes or Earth browsers. Google also refers to Google Earth as a "geographic browser." Other examples of geobrowsers are NASA's World Wind, ESRI's ArcGIS Explorer, GeoFusions's GeoPlayer, and EarthBrowser by Lunar Software.Google Earth is a beefed up map of the world. Instead of the normal 2D, a click-and-drag map you're maybe used to, Google Earth mimics the globe with a spherical map and stunning graphics so that you can zoom and glide over the oceans and cities of the world.
Beyond mere entertainment, Google Earth can also be used to find driving directions, locate nearby restaurants, go on virtual vacations, and do some serious research.
Google Earth isn't limited to just Earth; you can explore Mars, constellations, and the moon from the same program.
Google Earth's History
Google Earth was originally called Keyhole Earth Viewer. Keyhole, Inc was founded 2001 and acquired by Google in 2004.Founding members Brian McClendon and John Hanke remained with Google until 2015, when McClendon left for Uber, and Hanke headed up Niantic Labs, which was spun out of Google in 2015.
Google Earth Image Quality and Accuracy
Google gets images for Google Earth from satellite photos, which are stitched together to make a larger image. The images themselves are of varying quality.Larger cities are usually sharp and in-focus, but remote areas are often blurry. There are usually dark and light patches marking different satellite images, and some of the images are several years old.
The image stitching technique sometimes leaves problems with accuracy. Road overlays and other bookmarks often seem like they’ve shifted. In reality, the way the images were stitched together may have made the images shift position slightly.
Where to Download Google Earth
You can use Google Earth without downloading it, meaning that it runs straight in your web browser in seconds. However, you need Chrome in order to use it.To use Google Earth on a computer that isn't running Chrome, or on Windows, Linux, or Mac, you can install Google Earth Pro like a regular program. Doing this provides support for printing high-resolution photos, making movies, and importing for GIS data mapping.
Not coincidentally, many Google Earth features are also available on Google Maps. Google Maps has been incorporating features from Google Earth for years now, and it's likely Google Earth will eventually disappear as a separate product.
Google Earth Interface: Basic Controls
Google Earth opens with a view of the world from space. There are two ways to change the current perspective and easily navigate the globe: with the on-screen buttons or with your mouse.
Clicking and dragging on the planet will gently spin the globe. It moves just like items do on touch devices, where you can pull from left to right to rotate to a different area or push the globe up or down to see a different side of the world.
Using the middle scroll wheel or dragging and right-clicking simultaneously, will zoom in and out for close-up views. In some areas, the close-ups are detailed enough to make out cars and even people.
Clicking and holding the scroll wheel while moving the mouse is another way to rotate your perspective, which will come in handy if you're viewing 3D buildings.
On the right side of Google Earth are some on-screen buttons that also work to change the globe's position. The top control rotates the world, the one below it moves you around the globe, and bottom controls are used to zoom in and out.
What Are Google Earth Layers?
Google Earth can provide lots of information about a location — 3D buildings, border labels, photos, weather, images, and more — but viewing all of it at once easily clutters the map and makes it confusing to see any one thing at all.
To remedy this, the information is stored in layers, which can be turned on or off. Some other layers include roads, Wikipedia entries, airports, subways, banks, grocery stores, coffee shops, etc.
To enable or disable layers in Google Earth, locate the Layers section on the left side of the program, and place a check in the box next to any layer you want to see or remove the check to hide the layer.
Some layers are grouped into folders. Turn on all items in the group by clicking the box next to the folder, or expand the folder and enable/disable individual layers.
Two layers are useful for creating a 3D globe. Terrain simulates the elevation levels so that when you tilt your view, you can see mountains and other terrain objects. 3D Buildings is a folder of a few other layers that, when enabled, turns on Photorealistic, Gray, and Trees.
Search and Get Directions With Google Earth
Google Earth lets you jump to a specific place automatically, without clicking and scrolling, via the search area on the left side of the program.
Most addresses require a state or country, but for some larger US cities, you only need to type the name.
The Google Earth search function uses location awareness, so it will automatically suggest places near your current location rather than businesses or landmarks all around the globe.
For directions, click Get Directions under the search box. You'll be given two text boxes to provide a start and end location. You can also type in the regular search box, like from:Tulsa, OK to:Las Vegas, NV.
Create Google Earth Bookmarks
You can insert virtual thumbtacks into Google Earth to mark places for easier access again later, such as your house or your workplace. All of your saved places are located in the Places area on the left side of Google Earth.
To do this, click the yellow tack icon on the top of the program, and then drag the icon around on the screen. Name it whatever corresponds to the location.
How to Take Tours in Google Earth
Google Earth includes a sightseeing tour that takes you to various places of interest around the globe, like the Eiffel Tower, Grand Canyon, Sydney, The Forbidden City, and more.
What makes tours in Google Earth really neat is that the program takes you to each location automatically and then pauses so that you can explore that area. It even rotates around each landmark for several seconds so that you can get a full 3D view of it.
To start the Google Earth sightseeing tour, locate the Places pane on the side of the program, click Start tour here, and then select the camera button on the bottom of that section.
Google Sky, Mars, and Moon
In these other Google Earth modes, the user interface is nearly identical to Earth, so you can turn layers on and off, search for specific landmarks, leave placemarks, etc.
Application of Google Earth
Satellite images have many applications in -
A. Meteorology, B. Oceanography, C. Fishing, D. Agriculture, E. Biodiversity conservation, F. Forestry, G. Landscape, H. Geology, I. Cartography, J. Regional Planning, K. Education, L.Intelligence and warfare.
Images can be invisible colors and in other spectra. There are also elevation maps, usually made by radar images. Interpretation and analysis of satellite imagery is conducted using specialized remote sensing software.
Resolution and Data
There are four types of resolution when discussing satellite imagery in remote sensing-
Spatial Resolution is defined as the pixel size of an image representing the size of the surface area (i.e. m2) being measured on the ground, determined by the sensors' instantaneous field of view (IFOV).
Spectral Resolution is defined by the wavelength interval size (discrete segment of the Electromagnetic Spectrum) and a number of intervals that the sensor is measuring.
Temporal Resolution is defined by the amount of time (e.g. days) that passes between imagery collection periods for a given surface location.
Radiometric Resolution is defined as the ability of an imaging system to record many levels of brightness (contrast for example) and to the effective bit-depth of the sensor (number of grayscale levels) and is typically expressed as 8-bit (0-255), 11-bit (0-2047), 12-bit (0-4095) or 16-bit (0-65,535).
Google Earth uses GeoEye, DigitalGlobe, Spot Image, ASTER, BlackBridge, ImageSAT International and Meteosat.
0 Comments