by Chioma Innocent | Wed Dec, 2022 | Geospatial data, Remote Sensing, Satellite |
Techniques of Remote Sensing.
Remote sensing is detecting and monitoring an area’s physical characteristics by measuring its reflected and emitted radiation at a distance. The earth is scanned by satellites or high-flying aircraft in order to obtain information about it.
Two main types of remote sensing exist and are classified according to the source of signal they use to explore the object, active and passive.
Active remote sensing instruments operate with their own source of emission or light.
Passive remote sensing relies on the reflected emission to obtain information. Reflected sunlight is the most common source of radiation measured by passive sensors.
Passive sensors can only detect energy when naturally occurring energy is available. For all reflected energy, this can only take place during the time when the sun is illuminating the Earth. There is no reflected energy available from the sun at night. The energy that is naturally emitted (such as thermal infrared) can be detected day or night, as long as the energy is large enough to be recorded.
Active sensors, on the other hand, provide their own energy source for illumination. The sensor emits radiation which is directed toward the target to be investigated. The radiation reflected from that target is detected and measured by the sensor.
The advantages of active sensors include the ability to obtain measurements anytime, regardless of the time of day or season. Active sensors can be used for examining wavelengths that are not sufficiently provided by the sun, such as microwaves, or to better control the way a target is illuminated.
However, active systems require the generation of a relatively large amount of energy to illuminate targets adequately.
The sun provides a very convenient source of energy for remote sensing. The sun’s energy is either reflected, as it is for visible wavelengths, or absorbed and then re-emitted, as it is for thermal infrared wavelengths. Remote sensing systems which measure the energy that is naturally available are called passive sensors.
A random/common example is using a camera in sunlight. During a bright sunny day, enough sunlight illuminates the targets and then reflects toward the camera lens. The camera records the radiation provided. This can be described as remote sensing in passive mode.
On a cloudy day or inside a room, there is often not enough sunlight for the camera to record the targets adequately. So, it uses its own energy source – a flash – to illuminate the targets and record the radiation reflected from them. This can be described as an active mode of remote sensing.
by Chioma Innocent | Mon Nov, 2022 | GIS and Remote Sensing, GIS Application and Training, GIS Events |
Geographic Information Systems GIS is a tool mainly used to gather, analyse, and interpret data captured during the remote sensing process.
It is applicable in different sectors where it is used by professional analysts to analyse data for different uses.
Housing is one of the basic needs of humans along with food and water. A good shelter should protect the person in it from unfavourable weather conditions all year round.
Apart from natural disasters which occur occasionally, shelters should be able to withstand most conditions.
Even in cases of natural disasters, GIS has been known to help rescue efforts and help detect the best place to settle to prevent reoccurrences.
One of the main applications of GIS use in the housing sector has been in the area of dealing with environmental hazards such as floods, landslides, soil erosion, and drought. It is not possible to stop these events but GIS can be used to mitigate or decrease their impact
- GIS aids effective land administration, providing the platform for structured housing and land management.
- GIS can help individuals and businesses protect property rights, encourage open and competitive real estate markets, bring efficiencies in land administration (SDI, government, taxation, land consolidation etc)
- GIS aids in Land Use Classification and planning.
- GIS aids in the creation and management of Creation of address registers in partnership with local government areas, for easy analysis and upgrade of community database and mapping.
- Besides mapping areas in real estate, GIS can also play an important role in spatial analysis and determination of the absolute location where houses need to be situated.
- GIS Makes Performing Market Analysis Better: Market analysis is one of the most essential steps in housing. Research needed for each may differ in depth, but both require analyzing comparative sales in a given location. Prior to analysis, additional research is conducted on comparable properties recently developed in the subject property’s area.
- GIS enables tasks including site selection, land suitability analysis, land use and transport modelling, the identification of planning action areas, and impact assessments.
by Mercy Oriabure | Wed Mar, 2022 | Geoinfotech Blog, News, Satellite |
Starlink service is now active in Ukraine – Elon Musk, this reply comes after a tweet from Ukraine Vice Prime Minister Mykhailo Fedorov. Where he entreated the Tesla CEO to provide the country with Starlink access via a Twitter post on Saturday.
Expanding Starlink coverage to Ukraine might definitely be an easy part of building alternative internet infrastructure.
A network of relay towers and a constellation of low orbits satellites provides Starlink’s internet service. Offering the Ukrainian security advantage, unlike the regular land-based internet infrastructure.
As taking down satellites would be a costly operation for Russia. These relay towers that Starlink uses to provide Ukraine with internet coverage are likely stationed in neighboring countries, where Russian troops can’t target them.
Even with this tweet, ”Starlink service is now active in Ukraine” – Elon Musk, however, booting this service in Ukraine doesn’t automatically mean Ukrainians can use it.
Hence to complete the network, end users in Ukraine will need to import Starlink satellite dishes to receive signals from the service.
With Musk’s statement that “more terminals [are] en route” to Ukraine, it is however uncertain during the time of war, how those supplies will reach Ukraine’s government in Kyiv. SpaceX didn’t immediately respond to requests for comment.
Fedorov didn’t say in his tweet why the Ukraine government wants to use the Starlink service. Ukraine has suffered multiple cyberattacks since Russian President Vladimir Putin ordered an invasion on Feb. 24, but the country’s internet service remains generally active and stable.
Ukraine’s government has made ample use of web services, such as the Telegram messaging app, to keep citizens informed of its wartime efforts, and ministers evidently continue to be active on Twitter.
Regions affected most have experienced internet outages, and it’s possible Russian troops could target Ukraine’s internet infrastructure, such as transmitter towers, as the war continues.
In a second tweet, Fedorov thanked Ukraine’s Ambassador to the U.S. Oksana Markarova for helping “swift decisions related to authorization and certification that allowed us to activate the Starlink in Ukraine”.
The tweet suggests Starlink wasn’t available before due to administrative roadblocks, rather than technical ones.
In view of Starlink’s website, the satellite internet service is expected to hit Ukraine in 2023, so the Twitter exchange between Fedorov and Musk appears to have hastened a rollout, already planned.
by Mercy Oriabure | Wed Feb, 2022 | Geoinfotech Blog, News, Satellite |
Landsat 9 is now Functional. NASA in its recent update has skyrocketed Landsat 9 since September 27, 2021, at 1:12 PM CST from Vandenberg Space Force Base in Santa Barbara County, California.
Landsat 9 has also been disengaged from the Atlas V rocket at 2:34 p.m. EST, connecting 80 minutes later to the ground station at Svalbard, Norway.
The main purpose for which the U.S. created the Landsat Satellite was to observe the global land surface in a continuous manner. Which enables the view of both inherent bodies and human-made changes over timescales.
The increase of big cities has also been recorded by Landsat over time. For instance, farming trends and changing events of coasts, forests, deserts, and glaciers within the planet.
The diverse movement of animals from big and small has been cataloged by the satellite.
Landsat as we know has been in partnership with NASA and the U.S. Geological Survey (USGS). Succeeding to the launch of its first satellite in 1972.
According to Karen St. Germain, director of the Earth Science Division at NASA Headquarters. “This partnership has yielded positive results like up-to-date data for users varying from farmers to planners and scientists. With this data, one can understand, predict, and plan for the future in a changing climate.”
Landsat 9 is now making its way to its final orbital altitude of 438 miles (705 kilometers). It will be in a near-polar, Sun-synchronous orbit.
With both satellites, Landsat 8 and 9 being functional, can capture the entire Earth every eight days is recorded.
Landsat 9 was designed in a way to last for 5 years in rotation to replace the aged Landsat 7. To correct build-up time and the gap in observations.
The captured image is used by Scientists and researchers in detecting occurrences such as fertility of farms, large forest and health, water quality, coral reef habitat health, and glacier dynamics.
Over the years, the availability of Landsat data has been made accessible to users to check and download at this USGS website. You can also see other images of Earth from orbit at the NASA Earth Observatory website.
Landsat 9 carries the following sensors:
Similar instruments on its predecessor, Landsat 8 (satellite), can also be seen in Landsat 9, with a few modifications such as the:
- Operational Land Imager-2 (OLI-2) for reflective band data.
- Thermal Infrared Sensor-2 (TIRS-2) for the thermal infrared bands.
- OLI-2 has a slightly improved signal-to-noise ratio over Landsat 8’s OLI.
- Landsat 9’s TIRS-2 is a Class-B instrument with a five-year design life and a key improvement of stray light correction, an issue that was discovered on Landsat 8’s TIRS (Landsat 8’s TIRS is a Class-C instrument with a three-year design life).
- As with Landsat 8, Landsat 9 has a higher imaging capacity than previous Landsat missions, allowing for more valuable Earth observations to be added into the USGS Landsat archive.
NASA’s Launch Services Program located at Kennedy Space Center in Florida has been able to manage the launch of Landsat 9. Landsat program will mark 50 years in July, and this comes after the launch of its first Landsat satellite.
And ever since, continuous coverage of Earth’s land surfaces has been provided by the above program body. Enabling earth observers and resource managers to fast track land cover, land use, and the impacts of climate change and monitor natural resources.
To remain informed about the Landsat mission, do visit www.nasa.gov/landsat9. To follow the news on Landsat 9, please visit https://www.usgs.gov/landsat-missions/landsat-9.
by Mercy Oriabure | Wed Jan, 2022 | Geoinfotech Blog, News, Satellite |
In the quest to launch a second satellite (Sat 2) into orbit, Nigeria has mapped out strategies to enhance the communications status of the nation.
Minister of Communications and Digital Economy, Prof. Isa Ali Pantami made it known during a one-day facility visit and interaction with the staff of the Nigerian Communications Satellite (NIGCOMSAT) in Lugbe, Abuja. Saying this was approved by President Mohammadu Buhari for the purchase of the Satellite.
The Minister had also gone further to lobby the Minister of Finance to ensure its inclusion in the 2022 Budget, However, the amount approved and how many satellites are to be purchased was not disclosed.
News gathered shows, the Federal government has allocated about N2.5 billion for the Satellite 2 project in the 2022 budget estimate.
In 2011 Nigeria launched that existing Sat1R, with a life span of 15 years which will expire in the next four years.
The approval and establishment of some subsidiaries under NIGCOMSAT were also made known by the minister. Saying it is part of the ongoing effort to revive the institution back to the part of progress and productivity.
“Since 2019, I have been so passionate about the success of NIGCOMSAT starting with the suspension of the privatization of NIGCOMSAT. As a matter of fact, I have secured the approval of Mr. President for purchasing another Satellite.
I went further to lobby the Minister of Finance to ensure that this is included in the 2022 budget. I have also approved the establishment of some subsidiaries under NIGCOMSAT as part of efforts to revive the company and make it innovative and productive.”
The minister also told the staff of the company that the innovation in the agency is not enough and improvements need to be done.
In addition, he charged them to turn the institution around in order to justify the suspension of the proposed privatization plan.
He said, “Core values should be the guiding principle that must be adopted without compromise, to ensure that any institution is successful.
You need to be customer-centric, discover the failure of services before they realize it, fix the problem, and come up with innovative ideas. The innovation in the agency is not enough and needs to be improved upon
“You need to change your perception because you are not part of core civil servants; you are a company and should by far be above civil servants.
One of the reasons our civil service has been failing is that feeling that we are government employees, we have nothing to lose and whatever happens, we will be paid our salaries.
“There are other companies that are ready to come up and start providing similar services with you. The efforts made to stop privatization if NIGCOMSAT is for the good of the company and for the good of the country.”
