Accuracy Assessment of digital parcel map for Second-Level Land Demarcated Parcel in Case of Guahgot Kebelle, Eastern Tigray
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Date
2024-08
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Addis Ababa University
Abstract
Rural cadastral mapping in Ethiopia has significantly improved since 2003, when a parcelbased
demarcation system replaced the traditional method of registering parcels through written
documents. This rural cadastral map aims to comprehensively document the land’s history and
certify its usage types, including private, communal, state-owned, leased investment lands, and
other holdings. During this process, parcels are delineated using printed Orthophoto images
created from Remote Sensing or photogrammetric data.
This study examines the horizontal positional accuracy and validation of the digital parcel map
using in-situ total station measurements and direct digitization from digital orthophotos. The
digital parcel map’s horizontal accuracy is evaluated according to ASPRS standards and
general boundary criteria, computing the Root Mean Square Error (RMSE) independently for
both datasets and the RMSE in radial linear directions using thirty checkpoints. Additionally, the
validation of the digital parcel map is based on general boundary principles.
The planimetric accuracy of the digital parcel map for selected sample parcels is assessed using
total station measurements, determining the horizontal linear RMSE in the radial direction
errors for these parcel corners are 1.697 meters and 1.633 meters, respectively. Furthermore,
this study validates the area and perimeter of the digital parcel map using data collected through
total station surveys and digital orthophotos. During the validation of area for total parcels
within the kebelle, 8.21% (446 parcels) fall outside the general boundary standard (with errors
exceeding 17%) when compared to field measurements. Additionally, the validation of parcel
perimeters process reveals differences ranging from 3.61% to 0.48% for distances of 135 meters
and 270.547 meters, respectively, when using the total station. Comparing with digital
orthophoto measurements, the differences range from -7.41% to 0.14% for the same distances.
Based on the study findings, the second-level land demarcation process requires modernization
to align with ASPRS fixed boundary standards. To achieve better accuracy in digital parcel map,
the Rural Land Administration should prioritize the exclusive use of digital orthophotos for
large-scale map production.
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Keywords
Delineation, Demarcation, Orthophoto, Rural cadaster, Second level land certification, Spatial data