Engagement of gis digitizers for digitization of rice field boundary polygons

The main objective of this assignment is to engage qualified individuals ("Digitizers") to develop an accurate, consistent, and quality-controlled geospatial database of rice field and plot boundaries within designated areas of the GCF Knuckles Project area.

Specific objectives are to:

• Digitize individual rice fields and plot boundaries from high-resolution satellite imagery, basemaps, or other reference datasets designated by ICRAF.
• Produce topologically correct and spatially accurate polygon datasets.
• Follow standardized digitization protocols and attribute structures provided by ICRAF.
• Maintain consistency among multiple GIS operators working simultaneously.
• Support rapid preparation of field-level spatial data required for integration with the AgriLook platform and related project applications.
• Ensure that all digitized outputs undergo a transparent and systematic QA/QC process prior to acceptance and payment.

The Digitizer will be responsible for the following tasks:

• Review reference imagery (high-resolution satellite imagery, Google earth imagery as provided) and any existing cadastral border, or AI-survey area layers supplied by ICRAF.
• Digitize the boundary of each distinct field as a closed polygon in the specified GIS format (e.g., Shapefile/GeoJSON/GeoPackage, per project standard), following the field delineation and topology rules given in Section 5.
• Populate required attribute fields for each polygon (e.g., unique field ID, administrative division/GN division, land-use type, source imagery date, digitizer ID/date).
• Where assigned, cross-check digitized boundaries against ground/field survey points.
• Submit digitized polygons in batches according to the agreed schedule, through the designated submission platform/folder structure.
• Correct and resubmit any polygons flagged as non-conforming during the quality assurance review, at no additional cost, before they are counted as accepted for payment.
• Maintain a basic digitization log (area/tile covered, date, number of polygons submitted) for progress tracking.

Digitization Standards and Methodology

All polygons must be digitized to the following standard:

• Each polygon must represent one distinct, contiguous, single-cultivator rice field and plot, as visible on the reference imagery.
• Boundaries must be traced to the visible edge of the field (bund/ridge or adjacent land-use change) at a proper digitization scale (e.g., finer than 1:500, per project imagery resolution).
• No overlapping polygons.
• No unintended slivers, self-intersecting geometries, or duplicate polygons.
• Minimum mapping unit and positional accuracy tolerance to be specified by the project (e.g., ± [X] metres) before work begins.
• Correct coordinate reference system (CRS) as specified by ICRAF (e.g., WGS84 / SL national grid).
• Every polygon carries required attributes for (field ID, division, source date, digitizer ID).

Quality Assurance/Quality Control (QA/QC)

To safeguard data quality under the output-based payment model, the following QA/QC process will apply to every batch submitted:

• Automated checks: geometry validity (no self-intersections, no slivers), topology checks (no overlaps/gaps on shared boundaries), CRS/format compliance, and attribute completeness.
• Manual sample review: a GIS quality reviewer visually compares a sample of polygons against reference imagery for boundary accuracy and correct field delineation.
• Feedback loop: rejected polygons are returned to the Digitizer with the specific reason for rejection (e.g., boundary offset, merged fields, missing attribute) for correction and resubmission.
• QA sign-off: a batch is only marked Accepted, and therefore payable, once it passes the applicable QA checks above.