Satellite imagery has dramatically expanded the surveillance capabilities in many areas where it is needed today. Many industries, research projects, and environmental organizations rely on satellite data to assess changes and make effective decisions. One such example is forestry software, the work of which would have been impossible without satellite technology. In this piece, you will learn more about how satellite imagery is used and how current satellite images can be helpful for various sectors.
What Satellites Show Us
The influence of satellite technologies on various areas of human activity cannot be denied. For example, since 1973, it has become possible to monitor and control the condition of vegetation through the processing of satellite images. In addition, this information helps to track droughts in all regions of the world.
Satellite imagery is also invaluable in appraising damage and proving the impact of natural disasters. In 1986, satellite images helped to track the movement of the radiation plume after the accident at the Chernobyl nuclear power plant. Satellite images have also been used to assess the impact and identify damage following the volcanic eruption in Hawaii.
Satellites also show us how the human footprint on our planet is changing, including the expansion of cities and new settlements. Various human activities can be measured and recognized using satellite imagery. They can serve as evidence of serious human rights violations, illegal movement of people, and other crimes. In 1995, satellite images became evidence of mass executions during the war in Yugoslavia. They also made it possible to assess the extent of the cultural heritage objects destruction in Iraq and Syria.
Remote Sensing Imagery
Remote sensing is the primary method of obtaining data on earth resources and the environment on our planet. Satellite imagery has become a popular tool for obtaining information as it is easily accessible through the mapping applications Google Earth and Bing Maps. RS data and satellite images are provided in spectral, spatial, and temporal resolution.
Spectral statistics is responsible for the classification elements of remote sensing images. Spatial resolution is responsible for the accuracy of the definition of a ground object. Temporal resolution provides opportunities for the creation of land cover maps to aid in environmental planning. It is also necessary for observing land-use changes and assisting in the planning of transport systems. With the help of remote sensing, documentation of built-up areas is carried out, and the delineation of residential, industrial, and commercial spaces.
Satellite images quickly provide accurate information to help rescuers and other professionals assess the impact of disasters. A vital assessment tool is object-based image classification using change detection. It makes it possible to look at the object before and after the event and obtain data on damage assessment as soon as possible. These sorts of applications also use satellite imagery to create digital models and measure shadows from buildings.
Rapid population growth requires higher productivity from agriculture, as the demand for food increases with the number of people. Accordingly, agricultural resources need to be assessed before proper management of the available resources can be established. Geographic information systems and satellite imagery are essential for resource data collection and mapping. Agricultural land surveys and mapping are necessary to obtain information on livestock, pasture, and crops. Only by getting valuable information and collecting a large amount of reliable and accurate data will it be possible to develop an effective management strategy.
Urban and rural planning and other processes related to the arrangement and development of cities also use 3D GIS. Digital models of cities obtained using this technology significantly expand research possibilities and data on hard-to-reach, large and remote objects. All of this brings many benefits in planning, construction, BIM canal design, and water supply. 3D models of cities provide complete information about the vegetation, surface landscape, infrastructure, and buildings in the urban area.
Updating Local Web Maps with New Imagery
Up-to-date images can be helpful in many areas, including when it comes to urban environments. Snapshots allow you to identify illegal landfills, track new buildings, and much more. Unfortunately, these snapshots are not always available, as updating them can be pretty tricky. That’s why basemap providers often have slightly outdated content.
However, you can use a couple of different methods to obtain updated imagery for your web maps. These methods will be helpful for various specialists, including GIS managers. The first option is to purchase a subscription from custom basemap solution providers. The second option is to obtain images from a local aircraft or drone imagery provider, which are provided in a standard geospatial file format. They can be easily viewed in a GIS environment.
You will also need to transfer the resulting content to your WebGIS. The first step in the transfer process is to check the files and ensure they contain information about the coordinate system. This information should be stored in the header of the file. You can also open the file in your GIS system and view its properties to validate the information.
The next step is to check the file format. The format should be suitable for recognition by common imaging libraries. The most readable formats are:
- .img
- ENVI .hdr bitmap
- .bil
- .tif
The compressed .jpeg or.jp2 formats are not suitable as WebGIS systems will serve them as uncompressed slices of images.
TIF is an open format and, therefore, the most widely used. It is also capable of providing independent support regardless of software. This file has several flavors, including the standard old files of this format, which do not tell the program a coordinate system. There are also GeoTIFF files that contain geolocation and coordinate system data. Files BigTIFF helps overcome the 2GB limitation of the two files mentioned above types. It is better to use files of this format on modern GIS systems.
Before loading into WebGIS, you can take a few more simple steps to make sure the data is correct:
STEP 1: Make sure the data has a coordinate system
STEP 2: Check the file format
If the check is not successful, you can convert the files using GIS tools.
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