Chapter 3 Practical 3

Mapping of natural resources of a given study area using Google Earth

 

Aim:
To utilize Google Earth Pro as a Geographic Information System (GIS) tool to identify, classify, and map the distribution of key natural resources within a defined study area, and to analyze the potential for land use conflicts and environmental impacts related to their exploitation.

Principle:
Natural resources are materials and components that occur naturally within the environment and can be used for economic gain or human sustenance. They can be classified as:

1. Biotic: Derived from living organisms (e.g., forests, agricultural land, fisheries).

2. Abiotic: Derived from non-living, non-organic material (e.g., water bodies, minerals, land for construction).
   Google Earth provides high-resolution satellite imagery, historical data, and mapping tools that allow for the visual interpretation and spatial analysis of these resources. This process of thematic mapping helps in understanding resource distribution, abundance, and the spatial relationship between different resources and human activities.

Materials Required:

1. Computer: With internet access.

2. Software: Google Earth Pro (Desktop version). It is free to download and offers more advanced features than the web version.

3. Data Sources:

   • Google Earth layers (e.g., Borders and Labels, Photos)

   • USGS EarthExplorer or ESA's Sentinel Hub (optional, for specific satellite data)

   • Local government websites for land use maps (optional)

4. Notebook and Digital Spreadsheet: For recording observations and data.

Procedure:

Phase 1: Pre-Mapping Preparation (1-2 Days)

1. Define the Study Area: Select a specific region (e.g., your district, a taluka, a watershed area, or a 10x10 km quadrant). Clearly define its boundaries using latitude and longitude or a prominent natural/physical boundary.

2. Resource Classification: Create a classification system for the natural resources you will map. Use a consistent Color and Symbol Code.

   • Example:

     • Forests: Dark Green polygon

     • Agricultural Land: Light Green polygon

     • Water Bodies: Blue polygon

     • Mineral Quarries/Mines: Brown polygon

     • Urban/Built-up Area: Red polygon

3. Familiarization with Google Earth Pro:

   • Learn to use the Add Placemark, Add Polygon, and Add Path tools.

   • Explore the Historical Imagery tool (clock icon).

   • Adjust the Layers panel to show relevant information.

Phase 2: Digitization and Mapping (3-4 Days)

1. Base Map Creation: Zoom to your study area. Turn on necessary layers (e.g., Borders and Labels for village/town names).

2. Systematic Digitization: For each resource category, use the drawing tools to mark its extent.

   • Forests: Use the polygon tool to trace the outline of forested areas.

   • Agricultural Land: Trace large, contiguous patches of farmland.

   • Water Bodies: Trace rivers, lakes, reservoirs, and major streams.

   • Mineral Resources: Mark the location of visible quarries, sand mining sites, or mine tailings. (These appear as sharp, exposed earth patches).

   • Urban Area: Delineate the main urban or built-up zone.

3. Data Attribution: For each placed mark or polygon, fill in the description box with details:

   • Name/ID (e.g., "Western Forest Patch," "Main Reservoir")

   • Estimated Area (Google Earth will calculate this for polygons)

   • Observations (e.g., "appears dense," "seasonal crop," "active quarry")

4. Temporal Analysis (Optional but valuable): Use the Historical Imagery slider to go back 5-10 years. Observe and note changes:

   • Has the urban area expanded into farmland?

   • Has the forest cover reduced?

   • Has a new quarry appeared?

Phase 3: Analysis and Report Generation

1. Calculate Areas: Use Google Earth's built-in measurement tool for polygons to estimate the total area covered by each resource type.

2. Create a Map Legend: Ensure your color and symbol code is clearly displayed on the map.

3. Spatial Analysis: Analyze the map to identify patterns, overlaps, and potential conflicts.

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Observations & Data Analysis:

Table 1: Natural Resource Inventory of Study Area (Sample Data: 'X' District)

Resource Type	Color Code	Estimated Area (sq. km)	% of Total Area	Key Observations
Forest Cover	Dark Green	150	30%	Mostly dense in the northern hilly region.
Agricultural Land	Light Green	200	40%	Surrounds villages, along river plains.
Water Bodies	Blue	25	5%	Includes one major reservoir and two rivers.
Mineral Sites (Quarries)	Brown	5	1%	Two active stone quarries in the southeastern part.
Urban / Built-up Area	Red	120	24%	Concentrated in the center, along major roads.
**Total Study Area		500	100%

Map Output:
(Students will provide a screenshot of their final Google Earth map, showing all the digitized resource layers clearly. The map will include a Title, Scale, and Legend.)

[Insert Screenshot of Google Earth Map here]

Figure 1: Thematic Map showing distribution of natural resources in 'X' district.

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Discussion:

1. Linkage to Syllabus Themes:

• Land Resources: This map directly inventories land cover (forests, agriculture, urban areas). The percentage breakdown quantifies how this finite resource is allocated, which is the basis for understanding land use change.

• Causes of Deforestation: If historical imagery shows forest cover shrinking, the map can provide clues. Did the forest become agricultural land (economic pressure)? Or was it converted to an urban area (population pressure)?

• Impacts of Mining: The mapped location of quarries (mineral resources) can be analyzed. Are they near forests? Could they cause land degradation? Are they near rivers, posing a risk of water pollution from siltation?

• Water Resources: Mapping water bodies shows the natural and man-made sources (rivers vs. reservoirs). Their spatial relationship with agricultural land shows irrigation potential. Their proximity to urban areas or mines highlights pollution risks (over-exploitation and contamination).

2. Analysis of Spatial Patterns and Conflicts:

• Resource Conflict: The map may reveal direct spatial competition. For example, the urban area (red) might be expanding directly into prime agricultural land (light green). This is a classic land use conflict.

• Watershed Degradation: If quarries (brown) are located on hill slopes or near river origins (blue), they could be a significant source of siltation, affecting water quality and quantity downstream—a key issue in water resource management.

• Biodiversity Corridors: The arrangement of forest patches (dark green) can be assessed. Are they connected, allowing wildlife movement, or are they fragmented by agriculture and urban sprawl?

3. Limitations of the Method:

• Interpretation Error: Identifying resources based on visual imagery alone can lead to misclassification (e.g., a grassy meadow might be confused with a crop field).

• Scale and Detail: Google Earth is excellent for a regional view but may lack the detail to map very small resources or precise land use types.

• "Snapshot" in Time: While historical imagery helps, the map is still a representation of a specific time. Continuous monitoring is needed for dynamic management.

4. Connection to Broader Context:

• This mapping exercise is the first step in environmental planning. Planners use such maps to make decisions about zoning (where to allow mining, where to protect forests), disaster management (flplains), and sustainable development.

• It provides a visual context for syllabus case studies. For instance, seeing a dam's reservoir on the map helps understand the trade-off between water storage (a resource) and the submergence of forest and agricultural land (a cost).

Conclusion:

The practical successfully demonstrated the use of Google Earth Pro as a powerful and accessible tool for remote sensing and thematic mapping of natural resources. By creating a visual inventory of resources within the study area, the exercise facilitated a deeper understanding of their spatial distribution, abundance, and interrelationships. The analysis highlighted potential areas of environmental conflict, such as urban encroachment on farmland and the sensitive location of mining sites. This skill of geospatial analysis is fundamental for evidence-based resource management, conservation planning, and understanding the complex socio-environmental challenges discussed in the syllabus, from land degradation to water conflicts.

Viva Voce Questions:

1. What is the key difference between "land use" and "land cover" that you had to interpret in this practical?
   Land cover is what physically exists on the land surface (e.g., forest, water, concrete). Land use is how humans are using that land (e.g., a forest land cover may be used for timber production or conservation). I mapped land cover from imagery and inferred land use (e.g., I saw agricultural land cover and inferred its use is for farming).

2. If you saw a new, large exposed earth patch in your study area when using the historical imagery tool, what could it indicate and why is this significant?
   It could indicate the start of a new mining or quarrying operation or a large construction project (like a new dam). This is significant because it represents a rapid land use change that can lead to land degradation, loss of habitat, deforestation, and water pollution from runoff, directly linking to syllabus topics on the impacts of mining and dam building.

3. How could the map you created be used by a government agency to prevent a water conflict?
   The map clearly shows the location of water sources (rivers, reservoirs) and the major users of water (agricultural areas, urban centers). This helps in planning water allocation. For example, if a river is the only source for a city and a large farm, the agency could use the map to create policies to ensure equitable distribution and prevent over-exploitation that leads to conflicts.

4. What is one major limitation of using only satellite imagery for this kind of mapping, and how could you overcome it?
   A major limitation is the inability to understand ground-truth conditions. For example, I could map a forest, but I wouldn't know its biodiversity quality or if it's a protected area. To overcome this, the map must be validated with field visits and supplemented with official data from forest departments, land records, and zoning maps.

5. Based on your map, which natural resource in your study area appears to be under the most pressure from human activity, and why?
   [Answer will depend on the student's specific map]. For example, "Agricultural land appears to be under the most pressure. The urban area is expanding directly into it, as seen in the historical imagery where several light green patches have been replaced by red urban cover over the last 10 years. This represents a loss of a vital biotic resource that provides food and livelihood."