Geographic Information Systems (GIS) play a crucial role in various domains, and application development within this context involves creating software that leverages spatial data and tools.

Key components and considerations of GIS Application Development:

  • Data Collection: Gather spatial data from various sources (e.g., GPS, aerial surveys, sensors).
  • Data Storage: Organize data in databases (e.g., PostgreSQL with PostGIS, Oracle Spatial).
  • Data Processing: Perform spatial operations (e.g., buffering, overlay, routing).
  • Visualization: Create maps, charts, and interactive interfaces.
  • Analysis: Extract insights (e.g., proximity analysis, hotspot detection).
  • Integration: Combine GIS with other systems (e.g., web services, mobile apps).

Key GIS Development Tools and Techniques:

  • Programming Languages: Python (with libraries like GeoPandas, Fiona, ArcPy), JavaScript (for web-based GIS), Java, C#.
  • GIS Libraries and APIs: OpenLayers, Leaflet, ArcGIS API for JavaScript, Google Maps API.
  • Spatial Databases: PostGIS, Oracle Spatial, SQLite/SpatiaLite.
  • Web Mapping Frameworks: Mapbox, Carto, Esri ArcGIS Online.
  • Desktop GIS Software: QGIS, Esri ArcGIS.

Important Considerations and Challenges:

  • Data Quality: Ensure accurate and up-to-date spatial data.
  • Performance: Efficiently handle large datasets.
  • User Experience: Design intuitive interfaces for map interaction.
  • Security: Protect sensitive location information.

KNOWLEDGE OF DATA TRANSFER PROTOCOLS

KEY CONCEPTS AND TERMINOLOGY

  • Data exchange procedures - transfer constructs (based on data models):
    1. logical constructs solely pertaining to this standard,
    2. constructs relating to the implementation method, and
    3. constructs solely pertaining to the transfer media.
      1. File based transfer - data is in a structured file format.
      2. Application Programming Interface (API) - data is accessed and exchanged as needed between software systems.
      3. Web services - data is accessed and exchanged over networks and the internet between software components, using http and other web-based protocols.
  • Transfer of data between a client server and an end user
  • SSL – secure sockets layer
  • TLS – transport layer security (latest version of SSL)
  • SSL and TSL are used to encrypt data.
  • Network transport protocols:
    1. Communication packet is constructed at different intervals.
      1. Transmission Control Protocol – header package for the data at the transport layer
      2. Internet Protocol – header is added at the internet layer.
      3. Media Access Control (MAC) address – added at the physical network layer.
      4. Transferred from the host to the receiver.
  • Network File Services (NFS) - is a distributed file system protocol originally developed by Sun Microsystems in 1984. It allows users on client computers to access files over a computer network, much like local storage is accessed.
  • Common Internet File System (CIFS) - is a file-sharing protocol that provides an open and cross-platform mechanism for requesting network server files and services. CIFS facilitates seamless file sharing and resource access across networks, making it valuable for collaborative work and data exchange.
  • HTTP/HTTPS Protocols – Hypertext Transfer Protocol – standard web transmission protocol that uses the SSL/TLS protocol for encryption– a way for delivering map images or map data to web browsers.

SAMPLE QUESTION

Which protocol is commonly used for secure communication between a web browser and a website?

A) HTTP

B) FTP

C) SMTP

D) HTTPS

Answer: D) HTTPS

Explanation: HTTPS (Hypertext Transfer Protocol Secure) ensures encrypted and secure communication over the internet, protecting sensitive data during transmission. The other options (HTTP, FTP, and SMTP) do not provide the same level of security.

KNOWLEDGE OF CODING, SCRIPTING, AND MODELING BASICS

Scripting in GIS is a powerful way to employ programming languages to automate tasks, customize existing tools, and create new functionalities and tools within geospatial systems and combine GIS with other systems.

KEY CONCEPTS AND TERMINOLOGY

  • Scripting – involves using programming languages to automate tasks, customize existing tools, and create new functionalities within geospatial systems. A script is interpreted by the software and computer rather than compiled like a program.
    • Used to manipulate, customize, and automate existing processes and software.
    • Allows tailoring a GIS tool to your specific needs.
    • Repetitive tasks can be automated, saving time and effort.
    • Scripts can be employed to handle large and complex data manipulation, analysis, and visualization.
    • Scripts can be used to combine GIS with other systems or web services.
  • Common Scripting and Programming Languages is GIS:
    • Python: Widely used due to its simplicity, readability, and extensive libraries (e.g., GeoPandas, Fiona). Typically employed for data processing, analysis, and modeling. Often combined with JavaScript for creating interactive web maps.
    • R: Popular for statistical analysis and data visualization in GIS. Typically employed for data processing, analysis, and modeling.
    • JavaScript: Essential for web mapping (e.g., Mapbox, Leaflet). Often combined with Python for creating interactive web maps.
    • SQL: Used for geospatial databases (e.g., PostgreSQL with PostGIS).
    • Java, C#, and C++: Relevant for Map Servers and custom GIS applications.
  • Object oriented programming (OOP) - programming paradigm based on concept of “objects” which are data structures that contain data in the form of fields (aka attributes) and code in the form of procedures (aka methods) - most common are class based.
  • Extensibility - system design principle where the implementation takes future growth into consideration - level of effort to extend the system and implement the extension.
  • Query expressions – select a subset of features or records for use in a process or calculation.

SAMPLE QUESTION

Which programming language is commonly used for automating geospatial tasks and customizing GIS workflows?

A) Java

B) R

C) HTML

D) Python

Answer: D) Python

Explanation: Python is widely used in GIS for automating data processing, creating custom tools, and integrating with other geospatial libraries. While other languages (such as Java, R, and HTML) have their applications, Python’s simplicity and extensive libraries make it a popular choice for GIS scripting.

AWARENESS OF BASIC APPLICATION DEVELOPMENT METHODS

Application development is an iterative process for creating software applications to solve specific problems or meet needs.

KEY CONCEPTS AND TERMINOLOGY

  • Types of application development methods:
    • Agile – a flexible and iterative approach to creating software. It emphasizes collaboration, adaptability, and delivering value to users. Software is developed in mini-increments and adding of the new functionality – i.e., 2- week sprints. Agile methodologies include Scrum, Extreme Programming (XP), Kanban, and others. These approaches share common values and principles, such as collaboration, adaptability, and delivering working software frequently.
      • Agile process includes:
        • Requirements Analysis - Agile teams work closely with stakeholders to understand user needs and define requirements. Instead of detailed upfront planning, they focus on creating a high level vision.
        • Design - Design decisions are made incrementally as the project progresses. The goal is to create a simple and effective solution that meets user needs.
        • Development - Teams build the software incrementally, adding features in short cycles (usually 1-4 weeks). Developers collaborate closely, and the code is continuously integrated and tested.
        • Testing - Testing is an integral part of Agile. Automated tests are written alongside code, ensuring that new features don’t break existing functionality.
        • Deployment - Working software is deployed frequently (often daily or weekly). This allows users to provide feedback early and helps identify issues sooner.
        • Review - Regular reviews with stakeholders ensure that the project stays aligned with user needs. Adjustments are made based on feedback.
    • DevOps – is a methodology in the software development and IT industry. Used as a set of practices and tools, DevOps integrates and automates the work of software development (Dev) and IT operations (Ops) as a means for improving and shortening the systems development life cycle.
    • Waterfall – Rigid linear model that contains phases similar to Agile but are sequential (requirements, design, implementation, verification, maintenance) – each phase must be complete before moving to the next phase.
    • Rapid application development (RAD) – condensed development process that produces high quality system with low investment costs.
    • Spiral development – combination of waterfall and RAD – combines the advantages of top-down and bottom-up concepts.

SAMPLE QUESTION

Which of the following best describes the Agile application development method?

A) A sequential and linear approach to software development, emphasizing thorough planning and documentation.

B) A flexible and iterative approach that values customer collaboration, adaptability, and responding to change.

C) A method that focuses on creating detailed design specifications before writing any code.

D) A process that relies heavily on formal testing and quality assurance.

Answer: B) A flexible and iterative approach that values customer collaboration, adaptability, and responding to change.

Explanation: The Agile methodology emphasizes incremental development, frequent feedback, and the ability to adapt to changing requirements. It encourages close collaboration with stakeholders and prioritizes working software over extensive documentation12.