RW02 — Land Area and Perimeter Determination Using Google Earth - Theory & Concepts

RW02 — Land Area and Perimeter Determination Using Google Earth

$Learning Objectives$

Define and trace a defensible visible boundary for an assigned real-world site using Google Earth.
Determine the approximate perimeter and enclosed area of the traced polygon.
Record representative boundary vertices, coordinates, boundary segments, and segment lengths.
Convert measured areas into appropriate engineering units, including square metres and hectares.
Prepare reproducible digital documentation using correctly proportioned figures, captions, and descriptions.
Discuss uncertainty, boundary interpretation, and the limitations of satellite-imagery-based measurements.
Prepare a professionally formatted digital or printed Research Work using the required Civil Engineering Standard A4 Format with Grid and an independently handwritten conclusion.

$Digital Reconnaissance Measurement$

A preliminary measurement obtained from digital maps, satellite imagery, or geospatial software to estimate dimensions, distances, areas, or site characteristics without conducting a formal ground survey.

$Boundary Vertex$

A point representing a significant change in direction along a polygon boundary. A defensible vertex should correspond to an identifiable corner, bend, intersection, or other visible feature that can be explained and reproduced.

$Closed Polygon$

A sequence of connected boundary segments in which the final vertex returns to the initial vertex, creating a completely enclosed area that can be measured.

$Group Designation and Assigned Study Areas$

Use the study area assigned to your group:

Group	Assigned Study Area
Groups 1 and 2	Burnham Park
Groups 3 and 4	Melvin Jones Grandstand
Groups 5 and 6	Mines View Park
Groups 7 and 8	Baguio Botanical Garden

Groups assigned to the same location must work independently. Each group must prepare its own polygon, vertex placement, measurements, tabulation, figures, remarks, and handwritten conclusion. Small differences between groups are expected because boundary interpretation, zoom level, imagery, and vertex placement can affect the result.

$Assigned Site Must Be Followed$

Do not change the assigned site without instructor approval. The paired-group arrangement is intentional: independently obtained results can be compared to demonstrate how measurement judgment and boundary interpretation influence digital surveying results.

$Activity Scope$

Locate the assigned site in Google Earth, establish a defensible visible boundary, trace a closed polygon, and determine its approximate area and perimeter. The final Research Work must document the site, boundary basis, polygon vertices, coordinates, segment lengths, total perimeter, total area, unit conversions, digital evidence, engineering interpretation, remarks, limitations, and a handwritten conclusion.

$Primary Measurement Platform$

Use Google Earth as the primary platform for the final polygon, area, perimeter, and measurement evidence. Google Maps or other mapping services may be used only as supplementary references for locating surrounding roads, landmarks, or access points.

$Not a Cadastral or Legal Boundary Survey$

The polygon produced in RW02 is an academic digital reconnaissance boundary. It must not be represented as a legal property boundary, cadastral survey, relocation survey, subdivision survey, or survey-grade determination. Legal and high-accuracy engineering boundary work requires appropriate survey records, control, monument recovery, field observations, and professional verification.

$Defining the Measurement Boundary$

Before measuring, decide exactly what portion of the assigned site will be included. Use visible and defensible features such as fences, walls, pavement edges, curbs, building limits, landscaped boundaries, paths, retaining structures, vegetation breaks, or other persistent physical features visible in the imagery. Do not trace an arbitrary outline simply because it produces a convenient polygon.

$Boundary Vertex Selection$

Use enough vertices to represent the actual geometry without creating unnecessary points. Place vertices at significant corners, direction changes, intersections, bends, or transitions between boundary features. Avoid many closely spaced vertices along a boundary that is essentially straight. Label vertices consistently as A, B, C, D, ... or P1, P2, P3, P4, ... throughout the map, tables, computations, and discussion.

$Google Earth Measurement Procedure$

STEP-BY-STEP

Open Google Earth and locate the assigned study area.
Verify the site using recognizable surrounding roads, buildings, landmarks, and site features.
Record the site name and the date of measurement.
Adjust the view to a near-vertical or top-down orientation before defining the polygon.
Examine the imagery and identify the visible features that will control the measurement boundary.
Select a clear starting vertex.
Trace the site in one consistent clockwise or counterclockwise direction.
Insert vertices at significant changes in boundary direction.
Close the polygon by connecting the final vertex to the starting vertex.
Inspect the polygon for missing corners, misplaced vertices, crossed segments, or inconsistent boundary interpretation.
Record the latitude and longitude of the required vertices.
Record or determine the approximate length of every boundary segment.
Record the total perimeter and enclosed area reported by Google Earth.
Convert the area into the required engineering units.
Capture the required digital evidence while the final polygon and measurements remain visible.
Prepare the boundary table, measurement summary, engineering interpretation, remarks, and limitations.
Transfer the finished work into the required Civil Engineering Standard A4 Format with Grid without changing the template proportions.
Answer the conclusion guide questions and prepare the final conclusion by hand.

$Consistent Polygon Direction$

Document the boundary in one continuous direction, for example A → B → C → D → E → A. Do not reverse direction midway through the boundary table. The final segment must return to the first vertex.

$Required Boundary Data Table$

Prepare a table with the following columns: Vertex, Latitude, Longitude, Boundary Segment, Segment Length, Boundary Description, and Remarks. The boundary description should identify the physical or visible feature represented by that segment or vertex. Keep sufficient coordinate precision to reproduce the approximate location without implying survey-grade accuracy.

$Required Measurement Summary$

Provide a separate summary containing the group number, assigned study area, measurement date, software used, polygon direction, number of vertices, total perimeter in metres, total area in square metres, total area in hectares, principal boundary features, and the main source of uncertainty.

Square Metres to Hectares

Convert a measured area from square metres to hectares.

A_{\mathrm{ha}} = \frac{A_{\mathrm{m^2}}}{10{,}000}

Hectares to Square Metres

Convert an area expressed in hectares to square metres.

A_{\mathrm{m^2}} = 10{,}000A_{\mathrm{ha}}

$Perimeter Verification$

Compare the Google Earth total perimeter with the approximate sum of the recorded boundary segments. Exact agreement is not required when values are obtained independently, but a significant difference must be investigated. Check for omitted or duplicated sides, incorrect units, mislabeled vertices, misplaced points, different measurement paths, or a polygon that was not properly closed. Do not alter raw values merely to force agreement.

$Required Digital Documentation$

The report must include digital evidence that demonstrates the measurement process and supports the final result. Every image must be technically useful, correctly proportioned, readable in the required Standard A4 Format with Grid, and placed inside a clearly defined figure box with a figure number, caption, and detailed description.

$Minimum Required Google Earth Images$

Image 1 — Site Location and Context: show the assigned site with recognizable surrounding roads, buildings, landmarks, or other location references.
Image 2 — Boundary Definition: show the visible features used to establish the selected measurement boundary.
Image 3 — Completed Polygon and Measurement: show the full closed polygon together with the reported area and perimeter whenever possible.
Image 4 — Vertices or Critical Boundary Detail: show representative vertex locations or an enlarged portion where boundary interpretation required engineering judgment.
Additional images may be added when they improve traceability, but the page-density rule must still be followed.

$Documentation Page Density and Image Proportions$

Each documentation page must contain at least 4 images and no more than 8 images. Maintain the original aspect ratio of every screenshot or photograph. Do not stretch, squash, or crop out measurement values, vertex labels, scale information, or other essential evidence. Use additional documentation pages when needed, with each page continuing to follow the 4–8 image rule.

$Figure Description Standard$

A proper figure description must explain more than what is visually obvious. Identify the site portion, vertex, segment, boundary feature, measurement, or uncertainty being shown and explain how the image supports the procedure or reported result. Descriptions such as “Google Earth screenshot” are insufficient.

$Engineering Interpretation$

Discuss how the measured area and perimeter could support preliminary civil-engineering work such as site reconnaissance, conceptual planning, approximate space allocation, access studies, comparison of alternatives, or preparation before a formal survey. Also identify tasks for which Google Earth measurements would be insufficient.

$Remarks and Measurement Observations$

The Remarks section may be digitally prepared. Use it to record actual observations, uncertainty, interpretation decisions, discrepancies, and conditions affecting the result. Do not use Remarks merely to repeat the final area and perimeter.

$Guide Questions for Remarks$

Which physical or visible features were used to define the site's boundary?
Which part of the boundary was easiest to identify, and why?
Which part was most difficult or ambiguous, and why?
Did buildings, trees, shadows, roads, terrain, or other features obstruct the apparent boundary?
How were vertices positioned in unclear portions of the site?
Did changing the zoom level affect the apparent boundary location?
Were additional vertices needed for curved or irregular portions?
Did the sum of the individual segments agree reasonably with the reported total perimeter?
If a discrepancy occurred, what is the most likely explanation?
What differences would you expect from the other group assigned to the same site?
Which measurement decision probably had the greatest influence on the final area?
What would you improve if the measurement were repeated?

$Google Earth Measurement Uncertainty$

Google Earth measurements are approximate. Uncertainty may result from imagery resolution and date, manual vertex placement, zoom level, structures or vegetation obscuring the boundary, terrain and three-dimensional display effects, coordinate display precision, and differences in user interpretation. Use a top-down view whenever practical and avoid reporting false precision.

$Terrain and Elevation Limitation$

Treat the RW02 polygon as a plan-view digital measurement. Google Earth guidance notes that area and distance measurements are estimates and that ordinary measurements do not account for changes in elevation. Sites with significant relief require appropriate field or terrain-based methods when true surface distances or high-accuracy quantities are needed.

$Conclusion Requirement$

The Conclusion is the only section that must be handwritten. It must synthesize the group's result, confidence in the boundary, principal uncertainty, lessons about vertex placement and digital measurement, appropriate engineering uses, and the need for field verification. Write a coherent technical conclusion rather than copying the guide questions as a question-and-answer list.

$Guide Questions for the Handwritten Conclusion$

What approximate area and perimeter were obtained for the assigned site?
How confident are you that the polygon reasonably represents the intended study area?
What was the largest source of uncertainty?
Which part of the site's boundary had the greatest influence on the result?
What did the activity demonstrate about the relationship between vertex placement and measured area or perimeter?
Why might another group measuring the same site obtain a different result?
For what preliminary civil-engineering tasks would your measurement be useful?
For what engineering or legal purposes would it be insufficient?
What additional equipment, control, field observations, or surveying procedures would improve reliability?
What is the most important surveying principle you learned from RW02?

$Required RW02 Report Organization$

Arrange the submission as follows: Cover / Activity Identification, Group Members and Assigned Study Area, Objectives, Study Area and Boundary Definition, Measurement Method, Boundary Vertex and Segment Table, Area and Perimeter Summary, Unit Conversions, Digital Documentation, Engineering Interpretation, Remarks, Measurement Limitations, Handwritten Conclusion, and References.

$Permitted Digital and Printed Submission$

RW02 may be prepared entirely digitally except for the Conclusion. Tables, maps, screenshots, captions, descriptions, computations, interpretation, remarks, limitations, and references may be typed. The completed activity may be submitted digitally or printed, but it must use the required Civil Engineering Standard A4 Format with Grid. If the final submission is digital, scan or photograph the handwritten conclusion clearly and insert it into the correct location in the final PDF.

$Mandatory Standard A4 Format with Grid$

Use the official Civil Engineering STANDARD A4 FORMAT WITH GRID for RW02. The linked format page provides the required file and instructs students to print/use the provided A4 grid. You may edit the template before download to add names and other necessary information, but do not recreate, crop, stretch, rescale, or substitute the template with an ordinary blank A4 page. Preserve the original grid and page proportions. When exporting or printing, use the template at its intended A4 size and verify that all text, tables, maps, and images remain readable.

$Submission Schedule$

RW02 is due on the next class meeting unless another deadline is announced by the instructor. The submission may be digital or printed using the required Standard A4 Format with Grid. Only the Conclusion is specifically required to be handwritten.

$RW02 Final Submission Check$

Correct assigned study area was used.
Group number and members are identified.
Google Earth was used for the principal measurement.
Boundary definition is explained and reproducible.
Polygon is closed and follows one consistent direction.
Vertices, coordinates, boundary segments, and segment lengths are complete.
Total perimeter and area include correct units.
Area is reported in square metres and hectares.
Required digital evidence is included.
Every documentation page contains 4–8 images.
Every image has a figure number, caption, and detailed technical description.
The official Standard A4 Format with Grid from the required format link is used.
The template's original page/grid proportions are preserved; no substitute blank A4 layout is used.
Engineering interpretation and Remarks are complete.
Measurement limitations are discussed.
The Conclusion addresses the guide questions and is handwritten.
References are identified.
The result is not represented as a cadastral or legal boundary survey.

RW02 — Required Data Tabulation

Use this structure as the minimum field or research data table. Add columns when the activity requires more detail.

Vertex	Latitude	Longitude	Boundary segment	Segment length	Boundary description	Remarks
A	Record	Record	A–B	Measure	Identify visible boundary feature	Observation / uncertainty
B	Record	Record	B–C	Measure	Identify visible boundary feature	Observation / uncertainty
…	Continue	Continue	Continue	Continue	Continue	Close polygon and document issues

Use the group-assigned site. Add a site-summary table containing Google Earth perimeter, area in m² and hectares, measurement date, polygon direction, number of vertices, principal boundary features, and the main source of uncertainty. Use the official Civil Engineering Standard A4 Format with Grid for the submitted work.

RW02 — Grading Rubric

Award points according to the evidence shown for each criterion.

Total: 20 pts

Criterion	Full-credit evidence	Points
Assigned site and boundary definition	The correct group-designated site is used; the boundary basis is defensible, reproducible, and clearly distinguished from a cadastral or legal boundary.	4
Google Earth measurements and checks	Polygon closure, area, perimeter, segment lengths, units, and the segment-sum/perimeter check are complete, consistent, and traceable.	4
Coordinates, tabulation, and unit conversions	Vertex coordinates, boundary descriptions, remarks, site summary, and square-metre/hectare conversions are complete and mathematically correct.	4
Digital documentation and required format	Required Google Earth evidence is readable, correctly proportioned, captioned, technically described, arranged at 4–8 images per documentation page, and placed in the official Civil Engineering Standard A4 Format with Grid without altering the template proportions.	4
Engineering judgment, remarks, and handwritten conclusion	Remarks address boundary uncertainty and measurement decisions; limitations are technically sound; the conclusion is independently handwritten and synthesizes the required engineering judgment.	4
Total		20 / 20

Scoring guide: full credit for complete, technically correct, traceable evidence; reduce proportionally for minor errors, incomplete work, or weak documentation.

RW02 may be prepared digitally and submitted digitally or printed, but it must use the official Civil Engineering Standard A4 Format with Grid. Only the Conclusion is required to be handwritten.

Key Takeaways

RW02 uses Google Earth to determine an approximate area and perimeter for an assigned Baguio City study area.
Groups 1–2 measure Burnham Park, Groups 3–4 measure Melvin Jones Grandstand, Groups 5–6 measure Mines View Park, and Groups 7–8 measure Baguio Botanical Garden.
Paired groups work independently so differences in boundary interpretation and vertex placement can be evaluated.
A defensible polygon requires identifiable boundary features, appropriate vertices, consistent direction, and complete closure.
Each documentation page must contain 4–8 correctly proportioned images with captions and technical descriptions.
The official Civil Engineering Standard A4 Format with Grid is mandatory for the RW02 submission.
RW02 may be digitally prepared and submitted digitally or printed, but the Conclusion must be handwritten.
Google Earth measurements are appropriate for reconnaissance and preliminary analysis but are not cadastral or survey-grade boundary determinations.

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