Google Earth provides satellite images of the planet which contains a lot of important data. You can easily identify various changes within your environment from any location without an actual visit to the affected spot.
Although basic skills in map reading can be of great help, a good knowledge of the area will enable you to identify changes instantly. You can easily see light brown sandstorm patterns on dryland that has been affected by desertification.
The effect of volcanoes, floods, hurricanes, earthquakes, and wildfires among other events that have taken place in recent times can also be observed. You can also see the effects of population growth, changes in the transportation system, different ecosystems, vegetation, and lots more. Good knowledge of landmarks within a region like conservation areas which are managed by the government can be identified easily.
If you are new to the area that you are viewing on Google Earth, an atlas or a reference map would be of great assistance. Major landmarks and other important features are named in maps, making it easy for you to locate other elements in a particular region. There are online mapping services that can be employed to enable you to understand certain changes that occur around you as seen in the satellite image.
For effective interpretation of the information contained in satellite images, here are some key considerations:
1. Identify the North
Identifying where the north is will enable you to figure out the exact position of certain elements in the satellite image. The satellite image should be oriented with the north towards the top for easy identification of certain features, just the way we use landmarks to find our way when we are lost. Knowing that the north is up, you can easily find certain structures that are to the east or west of a river or a city that is to the north or south of a mountain. On Google Earth, the north is oriented toward the North by default, so that you can easily match several elements to a reference map.
2. Find a Scale
You can zoom in on specific areas to view elements of nature like lakes, mountains, and rivers, as well as places of interest like schools, business locations, tourist centers, parks, and healthcare centers. It may even be possible to spot your house and cars parked on the streets, but viewing from a wider angle makes it possible to see the entire ecosystem.
The landscape scale makes it possible for you to figure out how far apart all features are on the satellite image. Some images may show 100 kilometers per pixel, allowing you to view a larger area at a time with less detail. Individual buildings and the road network in a city can be seen at close range, but they may appear as a dot on a smaller scale.
A detailed view can give specific information about the way changes in climate and flooding is affecting buildings and traffic. A wider landscape view will show you where the source of the water that is causing the flood as well as the valleys and mountain ranges that may be controlling the flow. It is advisable to know the scale before trying to interpret a satellite image.
3. Recognize Textures and Patterns
Being able to spot distinctive shapes or patterns will help you identify certain elements when interpreting satellite images. Farmlands often have unique patterns which make it easy to identify. You can also identify lakes, rivers, and seas due to the fact that they have unique shapes. Certain clearings may appear in geometric shapes and straight lines which could be canals, roads, or manmade boundaries can be spotted easily.
With this knowledge, you can track environmental changes easily. Craters and volcanoes look like circles, the mountains may be seen as bumps or wrinkles, and canyons appear as thick wavy lines surrounded by shadows.
The satellite images are displayed in blue, green, and red wavelengths, making it easy to identify natural elements. Water bodies usually appear blue but may look gray or brownish when it contains sediments or ice that reflect light. Plants appear in several shades of green where farmlands have a brighter tone and natural vegetation like forests look darker. The green color may turn pale or brownish in different seasons.
Bare grounds are usually brown with some deserts looking reddish due to the presence of iron oxides. Volcanic debris and burn scars on the ground would appear tan or dark brown but may eventually fade over time. Buildings in cities often appear gray due to the concrete used in their construction. Rooftops may give certain areas a different color tone which could be red, brown, blue, or green.
Black smoke from fires, gray haze or fog, as well as light brown sandstorms and volcanic ash may be seen from satellite images. They cast shadows on the ground that make them look like clouds.
Basic understanding of the above-mentioned factors will enable you to interpret satellite images with ease. Whether you are tracking natural events or studying satellite images for other reasons, Google Earth features several tools that will make your journey a smooth one.