FREE CONCRETE QA VISUALISER

Slab Level Heatmap Reporter

Convert surveyed floor points into a north-up colour map, quantify high and low areas and issue a clear slab-level compliance report.

✓ CSV survey points✓ IDW colour surface✓ Tolerance zones✓ PNG, CSV & PDF

SURVEY SETUP

Project, datum and tolerance band

Project Client Company Prepared by Slab / zone Drawing / specification Survey date Coordinate system Design level RL (m) PASS tolerance ± mm FAIL beyond ± mm Map resolution Interpolation power Point label Display range ± mm Measurement precision

Engineering note: the coloured surface is an interpolation between measured points. It does not prove levels between points unless the survey density and method are appropriate for the slab geometry and specification.

INPUT DATA

Surveyed slab points

Drop survey CSV hereRequired columns: Point ID, Easting, Northing, RL. Optional: Note.

Point ID	Easting	Northing	Measured RL	Note / location

VISUAL RESULT

North-up slab deviation heatmap

Survey points0

Minimum—

Maximum—

Mean deviation—

Standard deviation—

Within PASS band0%

DELIVERABLE

Issue the slab level report

Engineering conclusion Survey method and limitations

I have checked the design level, coordinate reference, input points and stated tolerance criteria used in this report.

GUIDANCE

How to create a reliable slab-level heatmap

Confirm the correct design RL. Check the structural drawing, finishes, falls, steps and datum before comparing levels.
Survey a representative grid. Include edges, openings, joints, columns, local high points and suspected low areas—not only convenient locations.
Import Point ID, Easting, Northing and RL. Use metres for coordinates and levels. Verify several records against the source file.
Set contractual tolerances. PASS and FAIL limits must reflect the approved project requirement and intended assessment method.
Interpret interpolation cautiously. Closely spaced points dominate the IDW surface. Abrupt steps, falls and construction joints should be analysed as separate zones.
Investigate exceptions. Confirm control, instrument setup, point identity and physical surface condition before ordering remedial work.

What do the colours represent?

Blue areas are below the design level, green is close to design and yellow–red areas are above design. The legend shows the actual millimetre range used.

What interpolation is used?

Inverse Distance Weighting (IDW) estimates each coloured grid cell from nearby measured points. The power setting controls how strongly local points influence the surface.

Can this assess slabs with designed falls?

This version compares points with one design RL. A slab with falls, steps or multiple design planes should be separated into appropriate zones or supplied with point-specific design levels in a future advanced version.

Is survey data uploaded?

No. CSV parsing, interpolation, drawing and report preparation happen in the browser.