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Data validation

Data validation tools surface inconsistencies in a project before they cause analysis errors or noisy output. The Data Validation panel holds two tools: the Explosive Scrubber, which removes explosive records whose weights are all zero or empty or whose type isn't defined in their criteria, and the Single-Part Shape Fixer, which converts imported single-part multi-part shapes to plain shapes so their front can be selected.

Learning objectives

By the end of this lesson you should be able to:

  • Explain why an emptied explosive still affects an analysis, and why an explosive with an undefined type can't be analyzed
  • Run the Explosive Scrubber and review what it would remove
  • Recognize when a scan result points to a data-entry mistake rather than harmless leftover data
  • Explain why some imported facilities can't have a front selected, and fix them with the Single-Part Shape Fixer

Explosive Scrubber​

When a trainee sets an explosive's weights to zero or clears them, the explosive record is not removed from the feature — only its values are emptied. The analysis engine still sees an explosive on that feature, runs the calculation against the empty record, and returns an unnecessary 0 ft required result. These empty records build up after edits, imports, and bulk operations and clutter analysis output.

Imports can also bring in explosives whose type isn't defined in their criteria, for example an explosive typed 1.4S when the criteria only defines 1.4. The analysis engine rejects these, so they can never be analyzed.

The Explosive Scrubber finds both kinds of problem explosive and deletes the record from its feature, so the engine stops evaluating it.

For the click-by-click UI flow, see the how-to guide: Data validation.

Scan, then review​

Open the Data Validation panel from the label Popups menu and click Scan Features. The Scrubber lists each problem explosive with its Feature, explosive type (Explosive), Criteria, Attributes count, and Problem, with every row selected by default. The Problem column reads "Empty/zero weights", "Explosive type not defined in criteria", or both, separated by a semicolon.

Teach trainees to read the list before removing:

  • "Empty/zero weights" entries are safe to delete, but an entry is also the only visible evidence that a value was cleared by mistake. If a record appears here for a facility that should carry a weight, that points to a data-entry error. Have the trainee open that feature and check its explosives before scrubbing
  • "Explosive type not defined" entries may still hold real weights. Removing the record deletes those weights, so have the trainee re-enter them under a type the criteria defines before scrubbing

When to scrub​

Run the Scrubber:

  • After bulk edits that may have zeroed weights
  • After importing a project from an external source, where undefined explosive types usually come from
  • Before major deliverables, to keep analysis output clean
  • When stray 0 ft required results are cluttering an analysis

Do not blindly remove entries you did not expect — investigate the feature first.

Try it: Explosive Scrubber​

In a sandbox project:

  1. Add a feature and enter an explosive with a weight
  2. Edit that explosive and set its weight to zero (or clear it) — note the record is still on the feature
  3. Open Data Validation from the label Popups menu and click Scan Features
  4. Confirm the now-empty explosive appears in the results
  5. Leave it selected, click Remove Selected, and re-scan to confirm the list is clear

Single-Part Shape Fixer​

GIS files often store a facility's outline as a multi-part shape (a MultiPolygon) even when it has only one part — QGIS and ogr2ogr commonly re-save files this way. Siter imports the shape as it is, and a facility with this kind of shape can't have a front selected. Trainees usually meet this as "Select Front doesn't work on the facilities I just imported."

The Single-Part Shape Fixer converts each of these shapes to a plain shape (a Polygon) with the same outline and holes, so nothing moves on the map. Shapes with two or more separate parts are real multi-part shapes: the Fixer counts them and leaves them unchanged.

Points to cover:

  • Scan Shapes lists each convertible shape with its Feature and Layer, every row ticked. Anyone who can open the project can scan; Convert Selected needs the Project Edit Permission
  • Converting marks analysis for each converted facility out of date — plan to re-run analysis afterward
  • A shape the server refuses stays in the list, unticked and marked Could not convert; the others still convert. Shapes deleted since the scan are skipped
  • Run the Fixer right after importing a layer, before setting fronts

Try it: Single-Part Shape Fixer​

In a sandbox project:

  1. Import a GeoJSON layer whose facilities are stored as one-part MultiPolygons (ask the trainer for a sample file)
  2. Open one imported facility's Shape tab and note that Shape Details shows its Type as MultiPolygon
  3. Open Data Validation from the label Popups menu and click Scan Shapes
  4. Confirm the imported facilities are listed, then click Convert Selected
  5. Reopen the facility's Shape tab, confirm the Type is now Polygon, and select its front
  6. Re-run analysis for the converted facilities
  • How-to guide: Data validation — step-by-step Explosive Scrubber and Single-Part Shape Fixer instructions
  • Importing layers — imported layers are the usual source of single-part multi-part shapes
  • Bulk feature editing — bulk operations that often leave zeroed explosives behind
  • Importing a project — imports are a common source of empty records