Sequence of GIS Activities| Practical Work in Geography Class 12

In this article, we will look into the topic of “Sequence of GIS Activities” from the NCERT Class 12 Practical Work Geography book. These notes are specially curated by an expert team at GeeksforGeeks for all the students.

Spatial Data Input

Creating a spatial database in a GIS can happen in two ways:

1. Getting Digital Data from Suppliers: Nowadays, there are places where you can easily get digital data, like maps, from small to big ones. This is helpful for local governments and businesses because they don’t have to spend time and money making their data. But when combining data from different sources, you have to be careful. Differences in things like how the data is shown, the size, and the details might cause problems. So, before using the data, make sure it fits well with what you need by checking things like:
   • How big the data is
   • The system used to mark locations on the map
   • How the data was collected
   • How good the data is
   • How the data is sorted and filled in
   • How big and what shape each piece of the map is
   • How long the information is
2. Making Digital Data by Hand: Putting data into a GIS by hand involves four main steps:
   • Putting in the map data
   • Putting in the details about each place
   • Checking and fixing any mistakes in the map or the details
   • Connecting the map to the details if needed The way you put data in depends on whether the database uses points and lines (vector) or a grid (raster). The most common ways to put in map data are:
   • Typing it in
   • Scanning it With the first way, you mark down points and lines using coordinates. This can be done by looking at maps or photos or by putting a grid over them. Using scanners makes this faster and easier. Scanners are devices that change pictures or maps into digital images. There are two main types:
   • Ones that scan bit by bit
   • Ones that scan everything at once These scanners use light and special sensors to turn what they see into digital pictures. The scanned pictures aren’t always perfect, so sometimes you have to clean them up to use them.

Entering the Attribute Data

Attribute data is information about a place or thing that isn’t about its location. For example, if you’re talking about a road on a map, the attribute data might include things like how wide the road is, what it’s made of, how much traffic it gets, and any rules about driving on it. This information can be stored separately from the map itself, either in the GIS as part of a database, or along with the map in a special type of database.

You can get attribute data from different places, like official records, surveys, or spreadsheets. You can put this data into a GIS in two main ways: by typing it in manually or by bringing it in using a standard format for transferring data.

Data Verification and Editing

Spatial data in a GIS need to be checked for mistakes to make sure they’re accurate. Mistakes like missing bits or lines that don’t match up can happen when putting data into the system. One way to find these mistakes is to print out the data and compare it to the original map, looking carefully for any differences.

There are a few types of mistakes that can happen:

1. Missing or Extra Data: Sometimes, parts of the map might be left out or added in by mistake.
2. Wrong Scale: If the map is drawn at the wrong size, the data won’t be accurate.
3. Distortion: Maps or photos might be warped or changed, making the data wrong.

To fix these mistakes, special tools in GIS software are used. It can take a lot of time to correct them, but it’s important for getting the right information. Mistakes in maps with lines and shapes can be fixed by moving them around on the computer screen. Other tools can help change or delete parts of the map that are wrong.

When using different types of data together, like maps and photos, they all need to be in the same format. Sometimes, data needs to be changed from one format to another to make sure they work together correctly. For example, turning maps into grids or changing photos into lines and shapes. This is important for making sure the data is easy to work with and takes up less space.

Geographic Data: Linkages and Matching

Linking spatial and attribute data is a key part of using GIS effectively. If you connect the wrong kinds of data, it can make analyzing the information very confusing. Similarly, making sure different sets of data match up correctly is important too.

1. Linkages: GIS combines different data sets to help answer questions. For example, if we want to know how many children under 10 years old are affected by malnutrition in a certain state, we need to connect data about the number of children in that age group with data about malnutrition rates. Once these are linked, we can compare them to find the answer we need.
2. Exact Matching: Exact matching happens when we have data about the same things in different files, like information about towns in one file and more details about the same towns in another. We can easily bring this information together using a common key, like the town’s name.
3. Hierarchical Matching: Sometimes, data is collected in different levels of detail and at different times. For example, we might have detailed information about land use in big areas but less detailed info about changes in smaller areas. To make these match up, we can add up the smaller areas until they match the bigger ones.
4. Fuzzy Matching: In cases where the boundaries of smaller areas don’t line up perfectly with larger ones, we use fuzzy matching. This happens a lot with environmental data like crops and soil types. We overlay the maps and compare them to find relationships, even if the boundaries don’t match exactly.

A GIS can handle all of these tasks, but it’s important to remember that spatial information is only linked when it’s about the same place.

Spatial Analysis

The power of GIS lies in its ability to analyze data. What sets GIS apart from other systems is its special ability to analyze data that has to do with places. These analysis tools use both the location and other details in the database to answer questions about the real world. By creating and using models, GIS helps us understand processes in the world around us. These models show us patterns in the data, opening up new ways of looking at things.

The goal of geographic analysis is to turn data into useful information that helps decision-makers. For example, GIS can be used to predict future trends in different places and at different times for various things. But before we can analyze anything with GIS, we need to clearly understand the problem and why we’re doing the analysis. It’s a step-by-step process to reach conclusions.

There are several types of spatial analysis that GIS can do:

1. Overlay Analysis: Combining different maps to make a new one.
2. Buffer Analysis: Creating zones around a point, line, or area to see what’s nearby.
3. Digital Terrain Model
4. Network Analysis

Let’s focus on Overlay and Buffer Analysis for now.

Overlay Analysis Operations: One of the main things GIS can do is overlay maps. This means putting two or more maps of the same area on top of each other to make a new map. It’s like putting tracing paper with different drawings on a light table. Overlaying maps helps us do things like track changes in land use over time or figure out where to put new buildings based on what’s already there. For example, we can compare maps of urban areas from different years to see how they’ve changed over time and where new developments have happened. This helps us understand things like urban sprawl. Similarly, overlay analysis helps us figure out the best places to put new buildings or developments based on the land’s current use.

Buffer Operation: Buffer operation is another important tool in GIS for spatial analysis. It creates a zone around a point, line, or area on a map, extending to a specified distance (see Fig. 4.11). This is useful for figuring out which areas or people are affected or not affected by certain facilities or services, like hospitals, roads, or parks. It can also help study the impact of pollution sources on human health and the nearby population. This type of analysis is called proximity analysis. When we create a buffer, it makes a new shape around the original feature, showing how close other things are to it.

Sequence of GIS Activities: Short Notes

In GIS-related work, there’s a sequence of activities involved:

1. Spatial Data Input: This is where data collected from various sources is tested to see if it meets the needs of the investigator.
2. Entering Attribute Data: Attribute data describes the characteristics of a place or thing in GIS, like the width of a road or the type of surface. This information is added to the GIS along with the spatial data.
3. Data Verification and Editing: Spatial data in GIS needs to be checked for errors and corrected to ensure accuracy. Mistakes like missing or misplaced data can happen during digitization. To find and fix these errors, maps are printed out and compared to the original.
4. Linking Spatial and Attribute Data: Connecting spatial and attribute data correctly is crucial in GIS. If they’re linked incorrectly, it can cause confusion during data analysis. Also, matching different layers of data is important for accurate analysis.
5. Spatial Analysis: The goal of geographic analysis in GIS is to turn data into useful information for decision-makers. This involves step-by-step procedures to reach conclusions. Some common spatial analysis operations in GIS include overlay analysis, buffer analysis, network analysis, and creating digital terrain models.

Sequence of GIS Activities- FAQs

What is GIS in Geography Practical Class 12?

The full form of GIS is the Geographic Information System. It is a system designed to capture, evaluate, manipulate, handle, and view all forms of geographical & spatial information and data.

What are the practical applications of GIS?

The top applications of GIS include mapping, telecom services, urban planning, smart city development, environmental management, water management, agricultural applications, disaster management, healthcare sector, navigation, natural resources management, mineral exploration, banking sector, digital taxation etc.

What is spatial information technology class 12 practical?

In other words, the use of technical inputs in collecting, storing, retrieving, presenting, manipulating, managing, and analysing geographic information is referred to as Spatial. Information Technology.

What are the 5 components of GIS?

A working GIS integrates five key components: hardware, software, data, people, and methods. 

What is the sequence of GIS activity?

Creating digital data sets by manual input. The manual input of data to a GIS involves four main stages :
• Entering the spatial data.
• Entering the attribute data.
• Spatial and attribute data verification and editing.