Manual, semi-automated or automated image-based electronic manifests of locate operations. Image layers may be selectively enabled or disabled for display to facilitate viewing of base images and/or categories of information overlaid on the base image(s) relating to the locate operation. Accuracy indicators and/or calibration factors may be employed to ensure geographic integrity and appropriate registration of displayed information. Revision layers may be employed so that “raw” data, modified data, and/or annotated images may be maintained and locked to prevent unauthorized modifications. Limited access files may be employed to prevent unauthorized edits or use. Base images may be sketched manually with a drawing tool, and/or edge-detection and other image processing algorithms may be employed to improve feature recognition and/or remove undesirable features. Safeguards are employed to ensure that manifests are created at or near the work site, and information in the manifests may be analyzed to assess labor/material costs.