Top 10 Essential GIS Developer Interview Questions and Answers

Taking up a job as a GIS developer calls for specific knowledge on the core aspects as well as the more complex issues of GIS. It is quite daunting to prepare for an interview or to even refresh the knowledge or questions and answers you need to have at the back of your mind. Thus, in this article, we provide the reader with the most important GIS developer interview questions and answers that will allow demonstrating one’s best and get the dream job in a vibrant area of GIS technology. Whether it is a fundamental theory, or an advanced concept of spatial data analysis, these are the real life concepts that you will need to get ready for your GIS developer interview.

1. What is GIS and how does it work?

Answer:
Geographical Information System ( GIS ) is a system that helps in capturing , storing, analyzing , managing and organizing geographical data. It operates based on layers of information that allow the display of spatial data and their connections. Each layer can distinguish between the kind of data that it shows, for example, road nets, use of the territory, altitude.

2. What are the different types of data used in GIS?

Answer:

The two main types of data used in GIS are:The two main types of data used in GIS are:

• Raster Data: This is made of an arrangement in a network of cells usually arranged in rows and columns where each cell holds information in form of value in the form of temperature, height or spectral value.
• Vector Data: This include point, line and polygon in the form of data. Points can denote spot, such as places, while lines can denote routes such as road or streams, polygons can depict areas such as lakes or boundary areas. 

3. What are the primary components of a GIS?

Answer:

The primary components of a GIS are:The primary components of a GIS are:

• Hardware: Laptops, notebook, and other hand held devices, and GPS unit.
• Software: GIS software application such as ArcGIS,SOFTWARE application of GIS such as QGIS.
• Data: Microdata, being divided into spatial and attribute data.
• People: Citizens and geographers information systems personnel.
• Methods: Main methods of data analysis and their implementation.

4. What is the difference between ArcGIS and QGIS?

Answer:

• ArcGIS: One of the comprehensive and segregated programs that are planned for Geographic Information System by Esri Company. It offers high level operations for spatial data analysis, data manipulation and presentation.
• QGIS: A software that runs on a geographic information system and can be used, and altered as and when desired by anyone and free of charge. It very much resembles ArcGIS and can read and write nearly all formats of data that exist.

5. How do you handle spatial data in a database?

Answer:
Spatial data can also be handled using extension of those databases as for example PostGIS, an extension of PostgreSQL, or SpatiaLite, a database extension of SQLite. Such databases as spatial supporting spatial query and index which helps in conveniently storing and identifying the existence of spatial data.

6. Explain the difference between Georeferencing and Geocoding.

Answer:

• Georeferencing: The process by which the spatial data particularly maps and images are oriented to a well known coordinates system so that the society can overlay with other maps and images that are geographic.
• Geocoding: The concept of acquiring addresses, or descriptions of places, and then mathematically precisely positioning of the places in terms of x, y Z axis.

7. What is a shapefile and what are its limitations?

Answer:

Shape file is a vector GIS data model which is frequently used in GIS application. It consists of at least 3 files such as . shp that contain geometry data and are usually referred to as vector layer files, . shx that contain shape index data and . dbf that contains attribute data. Limitations of shapefiles include:

• The absence of backing for topology.
• Setting of the maximum size of the file to 2 GB.
• Can only store one type of geometry, that could be a point, a line, or a polygon.

8. How do you perform a spatial join?

Answer:

A spatial join involves two datasets and consists in merging them according to their spatial connection. For instance, it is possible to combine a point dataset of schools with a polygon dataset of districts to generate the field which would show in which district a specific school is. This can be done using GIS software such as ArcGIS or QGIS and these software have tools for spatial joins.

9. What are some common spatial analysis techniques?

Answer:

Common spatial analysis techniques include:Common spatial analysis techniques include:

• Buffering: Drawing around a feature a space that is able to separate the feature from its surrounding environment and inhabitants.
• Overlay Analysis: Relation between the layers; overlaying multiple layers to identify relationships.
• Spatial Interpolation: Calculating of values at some points using other known points.
• Density Analysis: Estimation of the parameters of features distribution in the specified territory.
• Proximity Analysis: They therefore come up with broader categories that help for instance when determining the distance between features.

10. Describe a challenging GIS project you have worked on and how you handled it.

Answer:

The GIS project that I found rather difficult was a mapping of flood zones in a city. With reference to the technical aspect of the project some of the data sources that had to be compiled include elevation data, land use data and historical flood records. The difficulty was to make the data correct and compatible with that provided by other sources. I handled it by:

• Conducting thorough data validation and cleaning.
• Using spatial analysis tools to model flood zones based on elevation and hydrology data.
• Collaborating with domain experts to verify the results.
• Regularly communicating with stakeholders to ensure the project met their requirements.

These questions and answers should give you a solid foundation for a GIS developer interview.