Frequently Asked Questions
GIS – FAQ
A geographic information system (GIS) is a computer system for capturing, storing, checking, and displaying data related to positions on Earth’s surface. By relating seemingly unrelated data, GIS can help individuals and organizations better understand spatial patterns and relationships.
Hardware: The physical equipment used to collect, store, process, and display geographic data. This includes computers, servers, GPS receivers, scanners, printers, and other devices.
Software: The applications and tools used to process and analyze geographic data. GIS software allows users to create maps, perform spatial analysis, manage databases, and visualize geospatial information. Examples include ArcGIS, QGIS, and Google Earth.
Data: Geographic data is the fundamental component of GIS. It includes spatial data (coordinates, shapes) and attribute data (descriptive information). GIS data can come from various sources such as satellite imagery, GPS surveys, field observations, and existing databases.
People: GIS professionals and users who design, implement, and utilize GIS technology. These individuals have expertise in geography, cartography, database management, programming, and spatial analysis. They interpret data, create maps, and apply GIS tools to solve real-world problems.
Methods: The analytical techniques and workflows used to manipulate and analyze geographic data within GIS. This includes spatial analysis methods such as buffering, overlay analysis, interpolation, and network analysis. GIS methods enable users to derive insights, make decisions, and solve complex spatial problems.
People are responsible for data collection, management, analysis, decision-making, and application development in GIS. Data, on the other hand, forms the foundation of GIS by providing spatial and attribute information.
A geographic information system (GIS) is a computer-based tool for mapping and analyzing things that exist and events that happen on Earth. GIS technology integrates common database operations such as query and statistical analysis with the unique visualization and geographic analysis benefits offered by maps.
GIS is a technology that integrates, stores, manipulates, and displays geospatial data in a digital format. By using GIS, geologists can enhance their workflows, improve their decision-making, and communicate their findings more effectively.
GIS (Geographic Information System) can be difficult to define precisely because it encompasses a broad and evolving set of technologies, methodologies, and applications that intersect with various disciplines.
Google Maps serves as a powerful tool for mapping and location-based services, leveraging geographic data in a user-friendly interface. While it incorporates GIS-like functionalities, it is not considered a full GIS platform due to its focus on mapping and limited data analysis capabilities compared to dedicated GIS software.
GIS enables users to go beyond mapping by conducting advanced spatial analysis, modeling complex phenomena, and integrating diverse datasets whereas Maps are a primary output of GIS, serving as tools for communication, navigation, and decision-making based on geographic information.
GPS provides location-based services and real-time positioning, while GIS enables deeper analysis and understanding of geographic data through spatial analysis, modeling, and visualization.
Satellites provide a wealth of spatial data that enhances the capabilities of GIS for spatial analysis, mapping, environmental monitoring, disaster management, agriculture, infrastructure planning, and climate studies. The integration of satellite imagery into GIS workflows enables more informed decision-making and sustainable resource management.
GIS (Geographic Information Systems) plays a vital role in conservation by enabling the mapping, analysis, and management of natural ecosystems and biodiversity. It supports habitat mapping, species distribution modeling, protected area management, wildlife monitoring, invasive species control, and ecosystem services mapping. GIS helps prioritize conservation areas, assess environmental impacts, engage communities, and plan for climate resilience, fostering effective conservation strategies and sustainable land management.
GIS facilitates the assessment of climate-related risks such as flooding, drought, wildfire, and coastal erosion. By overlaying climate data with infrastructure, population, and environmental data, GIS identifies high-risk areas and assesses potential impacts. Climate professionals use GIS to investigate climate scenarios with 3D dynamic maps, time series simulations, and real-time interactive dashboards that scientists and nonexperts alike can understand.
GIS plays a vital role in addressing air pollution by visualizing and analyzing air quality data from monitoring stations to identify areas with poor air quality and track pollution levels over time. It maps and analyses sources of air pollution, such as industrial facilities and transportation networks, to prioritize regulatory actions and emission reduction strategies. Through these capabilities, GIS supports evidence-based decision-making and public health initiatives to mitigate air pollution and protect human health.
GIS is a specific technology and methodology used for managing and analyzing geographic data, whereas geospatial refers to a larger domain that includes GIS along with other spatial technologies and applications. GIS is a subset of the broader field of geospatial science and technology.
GIS connects data to a map, integrating location data (where things are) with all types of descriptive information (what things are like there). This provides a foundation for mapping and analysis that is used in Urban Planning and Development, Natural Resource Management, Environmental Science, Transportation and Logistics, Defense and Security, Utility and Infrastructure Management and various fields.
GIS (Geographic Information System) does not typically use “commands” in the same way that software applications might have specific commands. Instead, GIS software provides tools and functions that allow users to interact with and manipulate geographic data. These tools are accessed through graphical user interfaces (GUIs) rather than command-line interfaces.
There are two different types of GIS data, vector data and raster data. Vector data represents geographic features as discrete points, lines, and polygons. These features are defined by their geometry (coordinates) and attributes (associated information). Raster data consists of a grid of regularly spaced cells or pixels, where each cell stores a value representing a specific attribute or phenomenon.
GIS information is stored in specialized databases and file formats that are designed to efficiently manage and organize geographic data. The storage of GIS information depends on the type of data (vector or raster) and the specific GIS software being used. They are usually stored in shapefiles, geodatabases, grid formats (GeoTIFF) and other formats. The storage method is selected based on factors like data volume, complexity, scalability, and interoperability with GIS tools and systems.
GIS has revolutionized the way we perceive and interact with our world. GIS enables better decision-making across various sectors such as urban planning, public health, natural resource management, and emergency response. By visualizing data spatially, decision-makers can identify patterns, relationships, and trends that are critical for informed planning and policy development.
PostGIS – FAQ
PostGIS extends the capabilities of the PostgreSQL relational database by adding support for storing, indexing, and querying geospatial data. PostGIS features include Spatial Data Storage: Store different types of spatial data such as points, lines, polygons, and multi-geometries, in both 2D and 3D data.
PostGIS is an extension for PostgreSQL that allows storage and management of spatial data through two types: geometry for Euclidean plane operations suitable for precise, short-range tasks, and geography for spherical surface calculations ideal for global distances. It improves query performance with spatial indexes like R-tree, which efficiently store geometries’ location and extent. PostGIS also offers a broad array of spatial functions for complex operations such as distance calculations, intersections, proximity analysis, and coordinate system transformations, making it a robust tool for detailed geographic analysis in various applications.
PostGIS is used to enhance PostgreSQL databases with the ability to store and manage geographical and spatial data, enabling complex geographic queries. It supports a wide range of spatial functions for tasks such as mapping, routing, and spatial analysis. This makes it ideal for applications in urban planning, environmental monitoring, and location-based services.
No, PostgreSQL is a general-purpose relational database system, while PostGIS is an extension of PostgreSQL that adds support for geographic and spatial data processing.
In PostGIS, a raster is a data type that represents georeferenced grid data, primarily used for storing and analyzing images like satellite photos or digital elevation models. It supports various operations such as resampling and extracting pixel values.
PostGIS stores vector data in `geometry` or `geography` columns, which include points, lines, and polygons, each associated with a Spatial Reference Identifier (SRID) for spatial referencing. Raster data is stored in `raster` columns, representing grid-based imagery or maps, also linked with an SRID for georeferencing, facilitating efficient spatial querying and analysis.
PostGIS stores spatial data primarily in geometry, geography, and raster types for vector and grid-based data. It also supports formats like WKT, WKB, GeoJSON, and GML for interoperability and data exchange.
Remote Sensing – FAQ
Remote sensing is the technique of observing and analyzing the physical properties of an area by assessing the electromagnetic radiation it reflects and emits from a distance, often via satellites or aircraft. This method utilizes specialized cameras to capture images, enabling researchers to detect and study various Earth characteristics remotely.
There are two types of remote sensing instruments—passive and active.
- Passive instruments detect natural energy that is reflected or emitted from the observed scene. Passive instruments sense only radiation emitted by the object being viewed or reflected by the object from a source other than the instrument.
- Active instruments provide their own energy (electromagnetic radiation) to illuminate the object or scene they observe. They send a pulse of energy from the sensor to the object and then receive the radiation that is reflected or backscattered from that object. Scientists use many different types of active remote sensors.
Remote sensing can solve a variety of problems by offering a bird’s-eye view, enabling the collection of vast datasets over large areas in a single observation. This technique is effective in gathering data across extensive geographic regions quickly, making it invaluable for monitoring environmental changes, urban planning, and disaster management. Additionally, with the capability to capture data in all weather conditions, remote sensing ensures consistent monitoring, essential for applications like agriculture management and climate studies.
Yes, remote sensing is a geographic tool that primarily uses electromagnetic radiation to collect data about the Earth’s surface. It works by detecting and measuring radiation reflected or emitted from different surfaces, which is then analyzed to observe and assess various geographical and environmental conditions. This data collection method allows for extensive mapping and study of landscapes, ecosystems, and urban areas from a distance, providing critical insights for geographical analysis and decision-making.
Geographers use a variety of remote sensing techniques, measuring various types of energy, to study Earth’s atmosphere, hydrosphere, lithosphere, and biosphere.
LiDAR – FAQ
LiDAR (Light Detection and Ranging) is a remote sensing technology used in geography and other fields to measure distances and generate precise, three-dimensional information about the shape and surface characteristics of the Earth’s terrain.
Key features that LiDAR can find or detect are Elevation and Terrain, Vegetation Structure, Buildings and Infrastructure, Water Bodies, Coastlines and Shorelines, Archaeological Features, Terrain Change Detection, Geological Features. LiDAR’s ability to capture detailed 3D information about the Earth’s surface makes it a versatile tool for a wide range of applications.
Lidar — Light Detection and Ranging — is a remote sensing method used to examine the surface of the Earth.
LiDAR systems emit their own laser pulses, which are then reflected off objects and returned to the sensor. The system measures the time it takes for the pulses to return, allowing it to create a detailed 3D map of the environment, regardless of the ambient light conditions.
LIDAR data also provide the potential for GIS data development. Some examples of GIS data that could be derived from LIDAR data are building footprints, piers, groins, docks, and jetties. Docks, for example, could be digitized and attributed from a LIDAR-based shaded relief map.
LiDAR generates high-resolution digital elevation models (DEMs) that helps geologists understand the topography and structure of the landscape. It also facilitates the detection and monitoring of landslides, erosion, and other geomorphological processes which helps geologists assess slope stability, identify potential landslide areas, and study erosion patterns. It can identify fault lines, folds, and other tectonic features by revealing subtle changes in elevation. This information is essential for studying plate tectonics, seismic hazards, and earthquake risk assessment.
While LiDAR can provide valuable information about the Earth’s surface and its features, it does not directly measure subsurface properties or processes, which are the focus of most geophysical methods. Therefore, LiDAR is considered more of a surface mapping and remote sensing tool rather than a geophysical method.
LiDAR can penetrate through dense vegetation, such as forests and jungles, to reveal hidden or overgrown archaeological features that are not visible from the ground or through aerial photography. By filtering out vegetation in LiDAR data, archaeologists can detect subtle variations in terrain that may indicate buried structures, roads, or ancient landscapes. LiDAR data can generate highly detailed maps and digital elevation models (DEMs) of archaeological sites and landscapes. This information helps archaeologists understand the layout, spatial relationships, and topographic characteristics of ancient settlements, cities, and monuments.
Yes, LiDAR (Light Detection and Ranging) technology is used for navigation in various applications, particularly in robotics, autonomous vehicles, and aerial navigation systems. LiDAR sensors provide accurate and real-time 3D perception of the surrounding environment, which is essential for navigation and obstacle avoidance.
LiDAR and vision navigation represent different approaches to environmental perception and navigation. LiDAR excels in precise distance measurement and detailed 3D mapping, while vision navigation leverages image processing to interpret visual data for navigation tasks
LiDAR is not primarily designed for speed detection, LiDAR speed guns can be effective for measuring vehicle speeds at moderate to long ranges in traffic enforcement applications. The specific range and performance of LiDAR speed guns depend on the device’s specifications and operating conditions.
LiDAR requires direct line-of-sight between the sensor and the target object for accurate distance measurement. Objects obstructed by dense vegetation, buildings, or other obstacles may not be fully captured or may be misrepresented in the LiDAR data. LiDAR performance can be affected by adverse atmospheric conditions such as heavy fog, rain, or snow. These conditions can scatter or absorb laser light, reducing LiDAR’s effectiveness in capturing accurate data.
LiDAR systems emit their own laser pulses, which are then reflected off objects and returned to the sensor. The system measures the time it takes for the pulses to return, allowing it to create a detailed 3D map of the environment, regardless of the ambient light conditions.
Cesium – FAQ
Cesium Geospatial is a technology for 3D mapping and globe rendering, supporting various geospatial data formats like KML and GeoJSON. It excels in high-precision visualizations and time-dynamic simulations, making it ideal for applications in fields such as urban planning and flight simulation. Cesium integrates with other geospatial services, enhancing its utility for detailed geographic analyses. Its core is built on WebGL and WebAssembly for high-performance graphics in web browsers.
Yes, Cesium is available for free as an open-source plugin under the Apache 2.0 license. It’s extremely permissive, allowing the plugin to be used without cost, even in commercial applications. You can use it to connect to any source of 3D Tiles, which is an open standard.
Cesium is a tool for creating interactive 3D maps on the web, using a technology called WebGL for realistic visualizations. You start by setting up a Cesium Viewer on your web page, which lets you add different layers like terrain and images to your map. It also allows you to control views, zoom, and handle clicks, making maps interactive and engaging for users. This makes it a practical choice for projects that need detailed and dynamic geographic displays.
Yes, Cesium uses WebGL to render interactive 3D graphics directly in web browsers without requiring plugins. This allows for the high-performance visualization of global imagery, terrain, and 3D models, enhancing detailed geographic data interactions.
Cesium primarily uses the WGS84 ellipsoid model for its 3D views, providing a realistic representation of the Earth. For 2D and Columbus View (a 2.5D flat view), it utilizes a Web Mercator projection, common in many web mapping applications.
CesiumJS does not have stringent hardware requirements as it is a web-based library, but for optimal performance, particularly with complex 3D visualizations, it’s advisable to use a modern multi-core processor (such as Intel i5/i7/i9 or equivalent AMD), a dedicated GPU (like NVIDIA or AMD) for efficient WebGL rendering, at least 8 GB of RAM, and an SSD for quicker data access. A stable and fast internet connection is also crucial, especially for applications that heavily rely on streaming large datasets like high-resolution terrain and imagery.
In Cesium, the Cartesian3 class represents points or vectors in three-dimensional space using a Cartesian coordinate system, where the units are meters. This is especially relevant when dealing with positions defined relative to the center of the Earth in the Earth-centered, Earth-fixed (ECEF) coordinate system.
To use Cesium in a React application, you can integrate it using the `resium` library, which provides React components for Cesium, ensuring compatibility and easier management of Cesium elements within React’s architecture. Configure Cesium in React by installing `resium` and `cesium` via npm, then use Resium components like `<Viewer />` to embed the Cesium viewer directly in your React components.
Yes, Cesium for Unity is free and can be used to create 3D maps, although Resium is specifically for integrating Cesium with React applications, not Unity.
The Rail Industry Geographic Information System (RIGIS) Portal is a specialized platform designed to enable dynamic GIS (Geographic Information System) mapping and application access for the railroad industry. It serves as a central hub where industry professionals can review, update, and share GIS data related to railroad assets. Users of the RIGIS Portal can create and share web maps and utilize various applications to visualize and analyze railroad data effectively. This portal supports a collaborative environment for data management and aims to improve the accuracy and availability of GIS data within the rail industry, facilitating better decision-making and operational efficiency.