What is Geospatial Data?
Ever wondered how your phone knows the fastest route to your destination or how scientists predict the weather? The answer lies in the power of geospatial data, a force revolutionizing our digital and physical worlds. Geospatial data refers to the information we can collect surrounding a natural or constructed feature, such as a forest or body of water's specific geographic location and unique characteristics. Typically, communicated with coordinates and a list of attributes, geospatial data gives users deeper insights into what they're observing and where and when changes occur.
Before you dive in:
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Components of Geospatial Data
Geospatial data has three key components: location data, attribute data, and temporal data. Location data refers to the "where" aspect of geospatial data and is typically expressed in coordinates, with latitude and longitude indicating the exact location from which the rest of the data was sourced. A coordinate system is beneficial in dense, undeveloped areas such as forests and vast bodies of water. Location data can also be expressed with addresses, postal codes, or other reference systems if that information is readily available. Next, attribute data refers to the "what" and "how" aspects of geospatial data. Attribute data is the descriptive information sourced from a specific location and typically presents details about geographic features. It can relay names of species, types of foliage, quantities of aspects present, and any other relevant characteristics. Attribute data can be qualitative or quantitative and serves to paint a picture of the specific coordinates overall. Finally, temporal data refers to the "when" aspect of geospatial data. Knowing when information was collected is essential for users who want to compare data at two different given points in time or who wish to monitor an area for changes as time progresses.
Types of Geospatial Data
First, there is vector data, which presents in three forms: points, lines, or polygons. Vector data represents geographic features using shapes and coordinates. Point data represents a specific location on a given map, such as a landmark. Line data represents linear features that connect at many points on a map, such as pipelines. Polygon data represents a distinct area, such as a country or property boundary. Vector data is exact when representing locations and scales very well without losing detail, meaning it is typically used for mapping and planning purposes.
Credit: Slingshot Simulations
Second, is raster data, which comes in two forms: discrete and continuous. It represents the Earth's surface in a grid format, giving each cell or pixel a value. A cell or pixel is the smallest unit of information in a given dataset, with pixel being an abbreviation for "picture element." These units represent information such as temperature or type of land use. Discrete raster data points have distinct aspects representing specific attributes like soil types. Each specific cell is definable and uniform, meaning the map output will look pixelated. For example, land use maps include specific attributes per cell corresponding to a different category of land use (industrial, agricultural), eventually producing a map of an area which shows you exactly how each referenced cell is used. Continuous raster data contain cells with attribute data that gradually change, such as temperature or elevation. Using a fixed registration point, such as a region's sea level, continuous raster data can demonstrate the variation in a region's elevation levels, which is extremely useful in topological analysis.
Development of Geospatial Data and GIS
Now that you have a rundown of geospatial data's components and types, you're probably wondering how it came into existence and why it matters. To give you an idea of geospatial data's impact on modern technology and decision-making, here is a historical timeline of factors and notable people who contributed to modern GIS.
Early Era ( Late BC - late 18th century)
The primary component of geospatial technology is a map. The earliest recordings of hand-drawn maps come from cartographers who charted their observations as they explored Europe, Asia, and Africa. Navigation tools like compasses (developed in early China) and telescopes (produced around 1608) helped refine maps by providing directional references like North and South. Interested in diving deeper into ancient cartography? Check out our blog post From Tusks to Tablets: Unearthing Ancient Cartography Before the Common Era.
Modern Era (Early 19th century- late 20th century)
In 1854, amidst the Cholera outbreak, Dr. Jon Snow drew the original link between the "what" and "where" aspects of modern-day GIS when he decided to map out the initial cholera outbreak locations, eventually tracing the epidemic back to a water pump. This discovery led to the conclusion that cholera was spread by water, not air, and also gave rise to the development of spatial analysis. Read more about GIS for public health.
In 1860, aerial photography was on the rise, with cameras mounted onto kites and balloons. This allowed people to chart the topological features of cities and rural areas.
The USSR launched its first satellite in 1957, and it has since been used for cartography, military surveillance, and communications.
In 1960, Roger Tomlinson developed the Canadian Geographic Information System, which implemented a layering approach to mapping. Around the same time, the US Census Bureau began digitizing census boundaries, roads, and urban areas.
Between 1960 and 1975, three essential things developed, making GIS what it is today: the new ability to output map graphics using line printers, advanced data storage capacities, and the processing power of mainframe computers.
In 1971, the development of total stations allowed users to measure distance and angles from the ground, revolutionizing civil engineering, construction, and map making. The total station further helped refine modern cartography and was essential in determining precise land measurements. Closely following the development of total stations was the creation of the Global Positioning System (GPS) in 1973, which allowed users to identify their current position on Earth.
Jon Snow’s Cholera Outbreak Map. Credit: The Chartered Group for IT
21st Century Creations
The development of the modern computer meant that technology was becoming faster, cheaper, and more accessible. With the influx of technological developments came the increasing accessibility to information, including satellite imagery, census data, detailed maps, and much more, further bringing GIS to the forefront of modern-day operations.
Drones or unmanned, remote-controlled aircraft are introduced to capture aerial images, chart areas, and assist in detailed map-making. Drone imagery, paired with artificial intelligence and machine learning, has revolutionized GIS and become a vital component in environmental monitoring, urban planning, disaster management, and many other disciplines.
Geospatial Data Technical Elements
To fully take advantage of geographic information systems, you must understand a few technical elements when compiling and analyzing geospatial data. With a basic understanding of topography and its rules, the types of spatial analysis, and government compliance standards, identifying quality and accurate information will be more accessible.
Topography
Topography concerning GIS refers to the physical relationships between aspects, and it is a crucial component that defines how data interacts with one another. Key concepts to note are:
Connectivity (how features connect at nodes).
Adjacency (the placement of features and how far).
Containment (determining which features are inside another).
There are a few rules to topography in terms of GIS, and following them ensures data integrity as well as spatial awareness. Firstly, polygons must not overlap with one another, i.e., land parcels must stay mutually exclusive. Second, all lines must connect at nodes, i.e., transportation lines must be connected and flow. Third, polygons must form closed rings, i.e., land boundaries must be complete without gaps. These three topological principles help keep vector data interpretable and accurate.
Spatial Analysis
When using geographical information systems, spatial analysis allows users to extract information and understand spatial relationships and patterns. There are several techniques behind spatial analysis, such as terrain analysis, which combines primary attributes such as flow direction and slope to form secondary attributes like stream power, and hot spot analysis, which identifies significant spatial clusters to observe areas with a high frequency of a specific attribute. Other techniques include buffer analysis, which creates and observes zones around geographic features; network analysis, which observes the pathways and connectivity of features; and overlay analysis, which combines spatial information with attribute data to observe relationships. These techniques identify relationships or observe the behavior of multiple attributes and are used in many fields. For example, hot spot analysis can display the frequency of crimes in a particular area, buffer analysis can display areas far enough from a protected land, and overlay analysis can show interpreters the soil quality of a given region based on land use. Recognizing what analysis is being conducted in a geospatial study or pinpointing what analysis you want to perform is imperative to creating and interpreting geospatial data.
Compliance Standards
In Canada, the Canadian Geospatial Data Infrastructure outlines the standards for producing, updating, and maintaining geospatial data. First, semantics refers to the meaning and structure of aspects used to demonstrate geographic phenomena. Digital geospatial metadata captures and relays data characteristics, representing the "who, what, where, when, why, and how" of the resource providing the data. Metadata records include information on database elements like attribute label definitions and domain values, library catalog elements like titles, abstract and publication data, and aspects like geographic extent (the area on the ground displayed in a map) and projection information (which coordinate system is used). Syntax refers to how the geospatial data is coded for communication between systems, meaning the format used for transferring and visualizing the data. Encoding rules stipulate what data types can be coded and which syntax, structure, or coding schemes should be used. Geography Markup Language (GML) and Keyhole Markup Language (KML) are Extensible Markup Languages (XML) that offer specific vocabulary to be used when working with geographic data and express geographic annotations and visualizations within two and three-dimensional earth browsers, respectively. A deeper explanation of all geospatial operational policies can be found here.
Applications and Current Uses of Geospatial Data
Having a comprehensive understanding of the terrain and environment gives business and government agencies the ability to make informed decisions, saving them time, money, and the required resources needed to carry out arduous research and monitoring tasks. From urban planning to public health to military and defence, geospatial data is revolutionizing the way organizations go about their business. Here is a brief glimpse into how GIS is being leveraged in select fields:
GIS for Emergency Management
A geographic information system's ability to chart, visualize, and synthesize data helps emergency coordinators immensely during natural or man-caused emergencies. Using terrain analysis, infrared drone imagery, and aerial mapping, GIS can assist in flood prevention, damage assessments, and search & rescue missions. When first responders have access to up-to-date terrain data, they can make informed decisions and coordinate resources, making their efforts more effective. For a deeper insight into GIS for emergency management, see here.
GIS for Forestry & Conservation
GIS offers valuable applications in forestry, from fire management to forest health monitoring. In forestry, assisted by drone capturing, GIS can create detailed aerial maps called orthomosaics, which can identify areas of concern, such as a fuel-rich environment during wildfire season or one devastated by deforestation and now prone to flooding. Also, using overlay analysis, GIS allows foresters to monitor forest health through forest cover analysis, density, and species identification. Sustainable forest management, fire risk assessments, timber harvest planning, and pest tracking are also enhanced by geospatial data. To delve deeper into GIS for forestry, check out this page.
For conservationists, GIS can streamline crucial processes such as biodiversity observation, species migration tracking, and habitat restoration and monitoring efforts using drone mapping and infrared imagery. Using hotspot analysis, conservationists can identify areas of migration activity or species habitats so they can map out proposed protected areas, habitat, and ecosystem changes and mitigate any potential threats to the area, such as flooding, fire, or instability. Through consistent mapping and monitoring, users can also chart restoration efforts and environmental regulation compliance and predict the environmental impact of future projects.
GIS for Transportation
Transportation planners can leverage GIS information to assist in route optimization, infrastructure management, and accident identification. They can utilize geospatial data in public transport tracking, improve scheduling, and assist in resource allocation to ensure that regions are properly served. Georeference mapping and aerial imagery can show areas where new lines could be developed, critically underserved areas, or locations with service disconnects. For more information on GIS and its implications in transportation mapping, see here.
Now, whenever you use the navigation system in your car or allow an app to use your location to curate services, you are taking advantage of geographic information systems and the geospatial data it analyzes! Hopefully, with the nitty-gritty technical elements of geographic information systems explained, you will be ready to leverage geospatial data in your personal or professional life.
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Cece + The Nova Team
