Survey Quality Report

The survey quality report aids in determining if there are issues with how a survey was performed and if an issue did occur during the survey, which topographic points are potentially affected by the issue.

Prerequisites

  1. Successfully run the Raw Survey File Processing Tool
    • e.g. have a Survey Geodatabase containing the QaQc_RawPoints feature class and tables Backsight_Log, Uncertainty_Summary, and SurveyInfo.

Steps

  1. Open the Review Survey Quality Report Tool.
  2. Answer the questions contained in the form.

Interpreting the Survey Quality Report

Much of the content contained in the survey quality report summarizes information about the point quality of the topographic points collected during the survey. For specific information about how point quality and its main components: vertical distance error (VDE) and horizontal distance error (HDE) are calculated visit this web page.

The Maximum Allowable Error for initial and revisit surveys is different, consider the visit type when reviewing the warnings presented in the survey quality report. Maximum Allowable Error specifications are described in detail below.

Point Based Accuracy Assessment

The Point Based Accuracy Assessment describes the uncertainty associated with each station and the points collected while occupying that station. By summarizing point quality for all points at each station and highlighting stations where average point quality is above the maximum allowable tolerance, this section enables the reviewer to quickly determine if any of the occupied points require closer attention.

Backsight Log

The Backsight Log provides more fine-scale detail than the point based accuracy assessment by isolating what occurred at each station event, which is defined as performing a backsight check, and includes occupying a station, potentially taking side shots, and ends with the next backsight check.

Fields in the table of this section that may require further attention are highlighted in orange or red depending upon how severe the issue is. For example, if a backsight check was performed for a station event with VDE higher than maximum allowable error, then the VDE cell for that record will be highlighted in red.

By clicking on cells in any of the warnings columns a modal window is shown that provides specific details about the warning(s) that occurred at that station event. For example, if a cell in the rod height column contains warnings and is clicked a figure is shown which plots all of the points collected at that station event and highlights in red points that have rod height warnings. By hovering over points in this figure as well as the square point number nodes in the affected points section the station event, point number, description, VDE, HDE, 3d point quality, and rod height are all shown for the particular point.

Maximum Allowable Error (MAE) Application Instructions

Initial Survey:

  • Horizontal Distance Error (HDE) = ± 0.03 m
  • Vertical Distance Error (VDE) = ± 0.015 m

Repeat Survey:

  • HDE = ± 0.05 m
  • VDE = ± 0.03 m

When to apply revisit or initial visit MAE values for benchmarks and control.

  1. When occupying a current year bm/cp:
    • apply revisit MAE when using any previous year point as backsight.
    • exception: apply initial for the point from previous year from which current year point was set will be backsighted.
    • apply initial MAE when using current year point as backsight.
  2. When occupying a previous year bm/cp:
    • apply revisit MAE when using any previous year point as backsight.
    • apply initial MAE when using current year point as backsight.