[QGIS Basics] QGIS Definitions, Main Functions, and Example Works

Hello,

In the first post for beginners of QGIS, I would like to explore what GIS is and where it is mainly used.

The Ministry of Land, Infrastructure and Transport of Korea defines GIS and its main functions as follows.

GIS Definition

• GIS (Geographic Information System) is an information system designed to efficiently utilize geographic information necessary for human life by converting it into computer data.
• An information system refers to a system that collects, observes, measures, inputs, stores, manages, and analyzes information to generate information necessary for decision-making.
• GIS integrates and manages positional data (spatial data) and attribute data to provide various forms of information such as maps, charts, and diagrams.
• In broad terms, GIS refers to an information system that supports human decision-making abilities, from observing and collecting geographic information to preserving, analyzing, and outputting it.
• Since GIS handles all data closely related to human real life, it has a wide range of applications. The applications of GIS are rapidly expanding across various industries including land, resources, cities, environment, transportation, agriculture, marine, and defense.

 

GIS Key Functions

• GIS represents all information in numerical form. All geographic information is stored in numerical data format, allowing users to select and output desired information in the required format. This surpasses the limitations of traditional paper maps by providing dynamic geographic information in three dimensions or more, beyond the two-dimensional concept.
• GIS quickly retrieves large amounts of data built on a computer-based system, easily combines geometric and attribute data, and provides an integrated analysis environment.
• Through the process of spatial analysis provided by GIS, it is utilized for analyzing scenarios for various plans or policy-making, operating decision-making models, and detecting and analyzing changes.
• The core function of GIS is to provide an environment where diverse geometric and attribute data can be extracted and combined from numerous data files containing various geometric and attribute data, enabling comprehensive information analysis and processing.

Source: Ministry of Land, Infrastructure and Transport National Spatial Information Portal (http://www.nsdi.go.kr/lxportal/?menuno=4066)

 

In summary, GIS is a tool that digitizes spatial information and easily combines it with attribute data, similar to Excel data, to produce another piece of information. It ranges from basic tasks like digitizing maps to managing scenarios and extensive calculations through modeling.

In the future posts, we'll practice step by step together, but here are some examples of advanced tasks you can do with GIS.

 

1) Obtaining information about places within a certain distance/travel time from a specific location

Map of general health centers within 15, 30, 60 minutes from the top hospital in Al Hoceima, Morocco During research/work, there are times when you need to find information about places within a certain distance or travel time from a specific location.

For example, you can use GIS to mark health centers within a 60-minute drive from top hospitals in Al Hoceima, Morocco, filter out those that are not within that range, and classify them as health centers with poor accessibility to tertiary healthcare systems.

 

2) Calculating the value of assets exposed to specific disasters

Population and proportion exposed to drought hotspots in Morocco in June, July, August 2021 (estimated) Also, in climate change-related projects, you might need to calculate the values of socio-economic indicators exposed in areas expected to be various disaster hotspots. Based on results overlaid from various sources like the map above, you can use GIS to draw regions in Vietnam expected to receive less than 70mm or 100mm of rainfall compared to previous years and calculate the total population living in those areas and their proportions (relative to the total population).

 

3) Calculating the value of assets exposed to climate change scenarios by modeling

Model input/output configuration If you have to deal with a large amount of data, handling them one by one is not efficient in terms of accuracy and speed.

 

In such cases, you can increase work efficiency by creating a custom model tailored to your research.

To effectively use the model, you need to understand various functions first.

Your judgment on how to connect input values and outputs in what order is essential because different functions need to be utilized.

 

For example, you can create a model to calculate the exposure of agricultural production levels based on climate change scenario data, as shown in the screenshot example above. We'll delve into such modeling examples in future posts under the advanced category.

It seems that there are more diverse tasks that can be done with GIS than one might think.

So, starting from the next post, let's learn QGIS basics together.

 

Thank you !!!