GeoJSON is a geospatial data interchange format based on JavaScript Object Notation (JSON). It defines several types of JSON objects and the manner in which they are combined to represent data about geographic features, their properties, and their spatial extents. GeoJSON uses a geographic coordinate reference system, World Geodetic System 1984, and units of decimal degrees. A GeoJSON object may represent a region of space (a Geometry), a spatially bounded entity (a Feature), or a list of Features (a FeatureCollection)

Example

 { "type": "FeatureCollection",
    "features": [
      { "type": "Feature",
        "geometry": {"type": "Point", "coordinates": [102.0, 0.5]},
        "properties": {"prop0": "value0"}
        },
      { "type": "Feature",
        "geometry": {
          "type": "LineString",
          "coordinates": [
            [102.0, 0.0], [103.0, 1.0], [104.0, 0.0], [105.0, 1.0]
            ]
          },
        "properties": {
          "prop0": "value0",
          "prop1": 0.0
          }
        }
       ]
     }

There a quite a few important points to note in the above example

• The order of elements (coordinates) must follow x, y, z order (easting, northing, altitude for coordinates in a projected coordinate reference system, or longitude, latitude, altitude for coordinates in a geographic coordinate reference system). Here is a good reference to check who is on which side of the LatLng debate
• The feature collection can support multiple different geometry types

GeoJSON supports the following geometry types:

• Point
• LineString
• Polygon
• MultiPoint
• MultiLineString
• MultiPolygon
• GeometryCollection

Is GeoJSON same as JSON?

While GeoJSON is a geospatial data interchange format based on JSON but GeoJSON follows a well specified Open data standard. For details read here

JSON because of its simplicity, flexibility and native support in Javascript has become the de-facto standard for the web developers similarly GeoJSON is now the de-facto standard for majority of OGC standards complaint Maps platform and libraries. Let us take a look at some examples

1. Leaflet – load geojson example
2. Openlayers – load geojson example
3. Mapbox – load geojson data example
4. Google Maps – geospatial analytics using GeoJSON in BigQuery
5. PostGIS – spatial extension for PostgreSQL database. You can store data is GeoJSON objects
6. MongoDB – you can store geospatial data as GeoJSON objects

Convert your data to GeoJSON

There are several open source tools for converting other geospatial data formats to GeoJSON, including:

• togeojson, a Node package for converting KML and GPX (XML formats)
• ogr2ogr, a vector data conversion tool
• geojson.io, a Mapbox developer tool for creating, converting, and editing GeoJSON

Happy Mapping !!!

GIS has undoubtedly been a tool to prepare, monitor and assess the impacts and magnitudes of disasters so that a disaster is not a foregone conclusion to humanity.

According to its definition, “Disasters are severe disruptions to the functioning of a community that exceeds its capacity to cope using its resources. Disasters can be caused by natural, artificial, and technological hazards, as well as various factors that influence the exposure and vulnerability of a community (IFRC, 2014).

Natural disasters are large-scale geological or meteorological events that can cause loss of life or property. These types of disasters include Tornadoes and Severe Storms, Hurricanes and Tropical Storms, Floods, Wildfires, Earthquakes, and Drought.

The topic of natural disasters is broad and highly compassing, drawing experts from all disciplines to comprehend the science and methods of coping with the devastating consequences. Given the recent emergence of natural events in the past few decades, large organisations such as the World Health Organization (WHO) and the United Nations have devoted considerable effort to research and education surrounding natural disasters. The United Nations International Strategy for Disaster Reduction (UNISDR), created in 1999 with the mandate of spearheading and coordinating disaster risk reduction, is an example of increased attention to disaster reduction (Prasad & Francescutti, 2016).

(A Radar Image of Tropical Cyclone Freddy approaching the coast of Madagascar on February 21^st 2023, which was coming at a wind speed of 220 km/hr.: Gif Source: AccuWeather Enhanced Real Vue satellite)

Damage caused due to the category five storm with more than 1,200 fatalities affecting 6 African nations towards the western part of the Indian Ocean; until now, it is one of the worst cyclones in 2023 by sheer magnitude:

Picture Source: Tropical Cyclone Freddy may set new record | World Meteorological Organization (WMO.int)

Man-made disasters have an element of human intent, negligence, or error involving a failure of an artificial system, as opposed to natural disasters resulting from natural hazards. Such artificial disasters are crime, arson, civil disorder, terrorism, war, biological/chemical threat, cyber-attacks, etc. (EMMC, 2019)

There is also another definition to it. Man-made Disasters are events which are caused by man, either intentionally or by accident, which can directly or indirectly cause severe threats, either directly or indirectly, to public health and well-being. Because their occurrence is unpredictable, man-made disasters pose an incredibly challenging threat that must be dealt with through vigilance and proper preparedness and response. Information on the primary sources of man-made disasters has been provided here to help educate the public on their cause and effects related to emergency planning. (Stallings, 1998).

They are classified into three types, namely Sociological, Technological and Hazardous material.

Sociology in disasters ranges from the ravages of war, civil disorder, communal violence, terrorism etc. At the same time, technological hazards deal with Industrial Hazard remnants to the ones like the Bhopal Gas tragedy. Other technological disasters like structural building collapse, Power outages, and Forest fires also fall under this category.

The Chornobyl disaster in the late 80s is considered an example of the worst catastrophe due to hazardous material.

The Chornobyl Disaster of 1986 is the worst radioactive manmade disaster: Picture Source: Wikipedia

Using Burned ratio Index, we can assess the damage of forest fires caused during the Russia-Ukraine War, a kind of man-made disaster using Earth Monitoring technologies: Gif Source: Sentinel Hub EO Browser

Disaster Management Stages and the Use of Earth Observation Technology

In this picture, the disaster Management cycle: Picture Source: Role of GIS in Disaster Management (rmsi.com)

There are four major stages which start with Mitigation. Phase 1 is mitigation towards the preparedness phase for a disaster event. Then likewise, we head towards response and recovery.

The “mitigation” phase occurs before a disaster takes place. Here, an organisation will protect people and property while decreasing the risks and consequences of a disaster. The main goal is to reduce vulnerability to disaster impacts (such as property damage, injuries, and loss of life) (Meaghan Kelly, 2020).

The “preparedness” phase also occurs before a disaster takes place. Here, an organisation attempts to understand how a disaster might affect overall productivity and the bottom line. The organisation will also provide appropriate education while putting preparedness measures into place. (Meaghan Kelly, 2020).

A Seismic Hazard Map of South Asia And the Middle East with the Intensity ranging from 0.00 to 1.50 PGA (g): Map Source: OpenQuake Map Viewer – Global Seismic Hazard Map

The Global Seismic Risk Map of the Asia Pacific shows interactive map imagery based on normalised construction cost in square meters. They are many areas in the Himalayan and Tibetan that have normalised construction costs of greater than 25000 Average Annual loss per square meter; these maps can help with potential mitigation impacts for construction-related activity which would be vulnerable during the earthquakes

(This is Global Exposure Maps of Earthquakes talks about the exposure of several buildings to an earthquake, What is depicted here is that there is over 250.0 K building exposed, which are in potential seismic zone areas in the Asia – Pacific region, which is critical to mitigation and preparedness: Source: https://maps.openquake.org/map/global-exposure-map/#6/29.162/86.554)

Most mitigation actions can prioritise locations where crises must be determined prior to any disasters.

What damage may occur based on the expected magnitude of an earthquake, characteristics of soils, and other geologic data? In the case of an earthquake, what developments are within the primary impact zone of earthquake faults? What facilities require reinforced construction or relocation? What facilities are in high-hazard areas (key bridges, primary roads, freeway overpasses, hospitals, hazardous material storage facilities, etc.)?(Johnson, 2000).

Preparedness would include actual emergencies. From answering where Fire stations are to be located and the relative response time that is expected, Planning evacuation routes from earthquake rubble to inland locations of coastal inhabitants during cyclones or tsunamis.

Terrain that caught forest fire during Russian Artillery shelling near Kyiv during the initial months of Russia – Ukraine War: Gif Source: Sentinel Hub

Real Time Maps can be used for preparing evacuation areas during a cyclone by tracking its projected path as seen from Tropical Cyclone path on Madagascar Island with Wind speeds exceeding 195 kilometres per hour. This is important in the response phase: Map Imagery Source: Zoom Earth

The “response” phase occurs in the immediate aftermath of a disaster. Organisations and well-being largely depend on preparedness levels before disaster strikes. Organizations must focus on threats to people, property, and business. (Meaghan Kelly, 2020).

GIS can provide one of the primary components for computer-aided dispatch (CAD) systems. Emergency response units based at fixed locations can be selected and routed for emergency response. The closest (quickest) response units can be selected, routed, and dispatched to an emergency once the location is known. (Johnson, 2000)

The “recovery” phase takes place after a disaster. This phase is the restoration of an organisation following any disaster impacts. By this time, the organisation has achieved at least some physical, environmental, economic, and social stability.

A disaster’s recovery phase can last anywhere from six months to a year (or even longer, depending on the severity of the incident). (Meaghan Kelly, 2020).

Flood monitoring becomes a critical component in response and recovery measures as Sentinel Timelapse monitors the extent of the inundated areas during the Floods in Assam 2022 at Silchar using NDWI Indices, which was a Natural cum Man Made disaster: Gif Source: Sentinel Hub

For Earthquake Response and Recovery, it is essential to monitor the Felt responses of aftershocks of the earthquake as shown by the Felt report of the recent February 2023 earthquake in New Zealand; Map Source: Geonet

Organizations using GIS in Disaster Management

One of the prominent organizations to monitor Disaster and Emergency Management is Company Planet. Planet’s high-cadence, high-resolution satellite monitoring capabilities and image archive provide ongoing regional coverage, enabling disaster risk mitigation, rapid response, and informed recovery. New Light Technologies (NLT), a leader in satellite-derived analytics and delivery of real-time decision-support systems for emergency management, works directly with FEMA to integrate near-daily Planet Scope imagery into its disaster response program. NLT and Planet help FEMA assess damages and plan recovery following incidents such as fires, hurricanes, and tornadoes. Planet and NLT rapidly deliver imagery through API and cloud-based platforms to streamline data access and integration with disaster response systems and commercial software platforms such as Esri ArcGIS and Google Earth Engine. (Disaster & Management, 2022).

In the United States, during the mega-drought, New Mexico’s Calf Canyon fire was the largest fire in the History of the State: Imagery Source: Planet eBook

Satellite imagery in which each pixel translates to 3.7 m2 on the ground. This could be used to detect organic matter from sewage overspills and their downstream impact, which is used to monitor Sewages in the UK by the Planet Satellite Imageries: https://content.planet.com/c/monitoring-sewage

Damage assessment also can be made through Planet high-resolution Imagery to assess the Impact of Hurricane Iota in a small village community on the coast of Nicaragua: Picture Source : (Disaster & Management, 2022)

Planet has just acquired Sinergise, a Slovenian based Satellite Cloud-based repository platform; in this Gif, we are observing Drought monitoring areas near Nairobi, Kenya, in February 2023: Gif Source: Sentinel Hub

(Real Time Emergency Management Operation logistic scheme representation of ESRI, another pioneer organisation in Disaster Management using GIS technologies: Source: ESRI)

The ESRI Emergency Management team which a fully integrated GIS system that enables the disaster management teams for situational awareness at all points during the disaster response stage.

Humanitarian Mapping and OSM 

When a powerful earthquake of 7.8 Richter scale struck the Levant region (Syria and Turkey), the Asia Pacific Open Mapping Hub used the Humanitarian Open Street Maps interface.

They were established in early 2021 and have extensively mapped in 25 different countries; they also provide financial and technical support to massively scale local edits on OpenStreetMap (OSM)

They are now actively working in Syria to map tasks in Aleppo and the surrounding regions.

( Image Source: The Asia-Pacific Open Mapping Hub affiliated with HOT have mapping using the HOT interface since 2021 and has mapped 25 countries so far that are prone to disaster: Picture Source: https://stories.hotosm.org/ap-homepage)

(In this Image, Open Street maps data that Yer Cizenler NGO is mapping is being used by AKUT Search and Rescue Association for helping and reaching out to the inhabitant. Source: https://www.facebook.com/YerCizenler).

References:

Disaster, P. F. O. R., & Management, E. (2022). Planet for Disaster & Emergency Management. 1–19.

EMMC. (2019). Man-Made Disaster | Monroe County, FL – Official Website. https://www.monroecounty-fl.gov/904/Man-Made-Disaster

IFRC. (2014). What is a disaster? – IFRC. http://www.ifrc.org/en/what-we-do/disaster-management/about-disasters/what-is-a-disaster/

Johnson, R. (2000). GIS Technology for Disasters and Emergency Management. Systems Research, May, 7. http://www.geo.umass.edu/courses/geo250/disastermgmt.pdf

Meaghan Kelly. (2020). 4 Phases Of Disaster Management Explained (The Easy Way). In AkitaBox.com (pp. 1–10).

Prasad, A. S., & Francescutti, L. H. (2016). Natural Disasters. In International Encyclopedia of Public Health (Second Edi, Vol. 5). Elsevier. https://doi.org/10.1016/B978-0-12-803678-5.00519-1

SAMHSA. (2022). Types of Disasters – Natural and Human-Caused Disasters | SAMHSA. In Substance Abuse and Mental Health Services Administration (SAMHSA). https://www.samhsa.gov/find-help/disaster-distress-helpline/disaster-types

Stallings, R. A. (1998). Man-made Disasters. In International Journal of Mass Emergencies & Disasters (Vol. 16, Issue 2, pp. 225–225). https://doi.org/10.1177/028072709801600210

Without geography, you are nowhere

Jimmy Buffet

It has always been a human endeavor to know the location of where a person is placed. From the Primitive times of Ancient Greeks, Herodotus coined the inhabited world as “Okiolumene” maps towards the age of explorations. Mercator maps gained popularity when exploration of the new world paved the way when the Naval ships used those maps. Maps which post-renaissance paved the way for European Colonization of most parts of the world.

In the picture, the earliest maps of Ancient Greek Historian Herodotus

Picture Source: Map of the World as Herodotus, The Father of History, Knew It (greekreporter.com)

Modern-day digital maps on smartphones have aided customers with routing guidance through GPS devices, which took much work to fathom during the wireless age. Maps certainly have come a long way from vast paper drawings towards fingertips movements on a smartphone device; behind this idea is the concept of GIS (Geographical Information System) that answers two vital questions: Where? And What?

It is hard to define it since it encompasses many elements comprehensively. Still, its closest definition in the true sense has been made by ESRI and National Geographic.

The National Geographic Society classified it as a geographic information system (GIS), a computer system for capturing, storing, checking, and displaying data related to positions on Earth’s surface. GIS can show many data on a map, such as streets, buildings, and vegetation. This enables people to see patterns and relationships more easily. (GIS (Geographic Information System), n.d.).

Another Prominent Map Software organization ESRI defined it as “A geographic information system (GIS) is a system that creates, manages, analyses, and maps all types of data. GIS connects data to a map, integrating location data (where things are) with descriptive information (what things are like there). This provides a foundation for mapping and analysis in science and almost every industry. GIS helps users understand patterns, relationships, and geographic context. The benefits include improved communication and efficiency and better management and decision-making (esriuk, 2019).

(The Concept of GIS fuses two elements of Attributes and Location)

In this picture, an excellent example of Attribute and Location is taken from a simple Google Earth Image of the Taj Mahal: Location element would be Latitude: 27°10’28.52″N Longitude: 78° 2’32.50″, Elevation: 631 feet, and the Attribute Element will be Taj Mahal and its relevant website tajmahal.gov.in along with the phone number of the tourist Centre would be its attribute element

Imagery Source: Google Earth Pro

GIS can use any information that includes location. The location can be expressed in many ways, such as latitude and longitude, address, or ZIP code. Many different types of attribute information can be compared using GIS. The system can include data about people, such as population, income, or education level. It can consist of information about the landscape, such as the location of streams, different kinds of vegetation, and different kinds of soil. It can include information about the sites of factories, farms, and schools or storm drains, roads, and electric power lines. (GIS (Geographic Information System), n.d.).

(As shown in this Image, Geographic Information Map is a combination of many-layered datasets:  Picture Source: gis.jpg (1024×905) (nationalgeographic.org))

Short History of GIS

The early days of GIS were very lonely. No one knew what it meant

Roger Tomlinson (Canadian Geographer considered to be the founder of GIS)

(In this picture taken, a brief timeline of the evolution of GIS: Source (History and Development of GIS, n.d.)

Although making maps was done eons time, the concept of layered mapping to provide Geospatial Information was first traced by John Snow’s Cholera Map of 1854 with the City of London suffering from the Pandemic; John Snow started Mapping Locations during the outbreak of cholera and found viable proximity to the city roads, residential or commercial properties and water lines of that time.

However, for the next 100 years, sieve mapping and paper maps became prominent within various thematic disciplines. It was not until 1960 when an employee of the Canadian Government, Roger Tomlinson, created the first layered map digitally of the Canadian Landcover. This was undoubtedly the age of pioneering for the field, and Roger Tomlinson is considered the Father of GIS. 

Many commercial establishments picked up from where Roger Tomlinson started a layered approach Mapping, including organizations like ESRI and commercially propagated the discipline of GIS through their Properties of ArcMap.

In this picture, a representation of John Snow’s Cholera Map where there could track the cholera outbreak due to an infected water pump

Picture source: 27636.jpg (990×743) (nationalgeographic.org))

The 90s marked a cornerstone era of locational Intelligence as the American GNSS (Global Navigational Satellite Systems) was declassified by President Clinton, which paved the way for commercial GPS technology with Portable Navigational devices within Locomotive vehicles. Locational navigational companies like TomTom, Garmin, and NAVTEQ were thriving.

Many Portable Navigational devices became famous as the American GNSS, better known as GPS, became declassified

Picture source: Getty Images

After 2010 however, the age when users of Geospatial data started to demand the need for greater access to Geospatial Information when smartphone devices became the talk of the town, many mapping platforms like Google Maps, Bing Maps and Open Street Maps became easily accessible to edit without any lucrative payment to access its geospatial information which during the majority of the GIS history was a norm to deal with.

In this picture: This is Humanitarian Open Street Maps account, where we map building footprints in Syria. By building footprints, humanitarian organizations and first responders can estimate building damages and the population density in these areas:

Source: http://hotosm.org/ 

Forms of Digital Data

(Data in GIS is stored in a Geodatabase, also called a Spatial Database; the data structures would include geometric vector properties like Point, Line and Polygon and Satellite or other remote sensing imageries in a pixel format called Raster files which are in turn stored in a SQL based Attribute table:

Picture source :(History and Development of GIS, n.d.)

GIS data is modelled into two formats Vector data and Raster data. Vector data is the most common type of GIS data. Most data loaded into a GIS software program is in vector data. Vector data represents geographic data symbolized as points, lines, or polygons. (Dempsey Caitlin, 202 C.E.)

Raster data represents geographic data as a matrix of cells containing an attribute value. While the area of different polygon shapes in a data set can differ, each cell in a raster data collection is the same cell. The size of the area in the real world that each cell represents is known as the spatial resolution (Dempsey Caitlin, 202 C.E.).

In this Image shows the representation of features in Points, Lines and Polygons; Individual Trees are represented in Point features, Settlements are described as Area features and rivers and roads are defined as Linear features

Picture Source: QGIS.org

A Representation of Raster data with color gradients

Picture source: Introduction to Raster Data – Introduction to Geospatial Concepts (datacarpentry.org)

Types of Digitization

The most popular form of converting Geographic data into digital form is digitization. Digitization involves tracing vector spatial data objects like lines, points, and polygons. Digital data is typically represented as numbers or symbols such as texts or graphics; The process involves converting Analogue images into digital ones. 

There are various types of digitization methods; Manual Digitization is a process in which an image is copied manually to create a digital file. It is done with the help of digitizing tablets with an instrument known as the puck. The highest accuracy comes through this method.

Shown in this Image is the process of Manual digitization with a tablet using a puck instrument on a digital tablet, while on the image on the right, raster digitization using a scanner

Picture source: USGS

Heads up, Digitization is scanning paper documents into digital files. It helps to digitize paper documents without the risk of damage or loss of the original documents. 

It also aids in making paperwork more organized and less time-consuming due to significantly cutting the troubleshooting time. Automatic Digitizing converts raster to vector data or 2D or 3D objects into digital data. The primary purpose of automatic digitizing is to increase the speed and efficiency of GIS data collection. With this process, it is possible to collect, organize, and manage large volumes of data efficiently. The primary goal of an automatic digitizer is to provide up-to-date spatial data in real-time. (Spatial Post, 2021).

In this Image, a conventional example of Heads up Digitization of a building

Picture Source: Link

The best form of Automated digitization is drawing on contour lines shown in a tiff file

Picture source: ESRI

Geospatial everywhere?

The application of GIS is limited only by the imagination of those who use it

Jack Dangermond, ESRI Co-Founder

Geospatial maps have been a cornerstone for daily activities. Whether it is to know the weather updates or for daily commutes, the dynamic nature of maps cannot be present. Organizations like Google, Apple, TomTom, and Here Maps have more than 1 billion Points of Interest Areas of Retail outlets, Monuments, Educational Hubs, Restaurants etc. Most navigation maps produced by Here and TomTom are used for daily commuting in various mobile applications of taxi services like Uber and Ola.

(In the map made on QGIS software and overlaid on Google, we can estimate the shortest path from Point A in South St NW Avenue to Point B in Logan Circle of Washington DC Streets: Picture Source: GREd Foundation Map Archives: GREd foundation – GREd Foundation)

(Many Logistics and service companies like Uber use base maps of Tomtom and Apple for their taxi routing services: Picture Source Uber)

Using HERE Maps as many logistic companies use in the base map Amazon locational services over the period for parcel delivery or fleet transportation, it also enables users to monitor their locational privacy settings, which are now become a prime importance

Map Source: HERE Maps on Amazon Location Service | HERE

Apart from navigation and locational intelligence, real-time maps are also used in many other applications ranging from disaster management, weather forecasting, tracking movements, ship cargo transport or, for that matter monitoring. live air traffic.

In this Map Imagery, an hour-by-hour update of Cyclone Freedy when it impacted the Island of Madagascar

Map Imagery Source: Zoom Earth

The tracking of Vessels and ships shown here near the Mumbai Harbor is another real-time Application that is useful for monitoring cargo movements

Map Imagery Source: Free AIS Ship Tracker – VesselFinder

Radar and Thermal Imagery are often used to track cloud cover and area temperatures, which is daily updated as shown in the radar weather imagery of India

Imagery Source: WeatherRadar – Rain, snow, storms and clouds live (weather and radar. in)

The current era of the geospatial revolution has ensured that maps are a part of our lives in this fast-moving digital world, and locational information is now a daily necessity for human mobility.

A GIS system typically includes three main components: hardware, software, and data. Hardware includes the computers and other equipment used to store, process, and display spatial data. Software includes the programs and applications used to manipulate and analyze spatial data, such as GIS software, database management systems, and programming languages. Data includes the geographic information used in a GIS, such as maps, satellite imagery, and demographic data.

There are many different types of GIS software available, ranging from open-source options like QGIS, to commercial options like ArcGIS. These software typically provide a wide range of tools for data management, data analysis, and map creation.

GIS can be used for a wide range of applications, such as:

• Creating and displaying maps, such as street maps, satellite images, and weather maps.
• Analyzing spatial data, such as identifying patterns and trends in population density or land use.
• Managing and analyzing spatial data, such as tracking changes in land use or the spread of invasive species.
• Planning and managing resources, such as optimizing routes for delivery trucks or managing wildlife habitats.
• In emergency response, GIS can be used to track and analyze incidents, plan evacuation routes, and manage resources.

Overall, GIS is a powerful tool that can be used to understand and make sense of our world, and it has been widely used in many fields and industries