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Isoconcentration and Plume Maps, with Non-Detects Handled Honestly

A plume map is only as defensible as its treatment of the values that were never detected. Here a non-detect stays a non-detect: it is posted with its reporting limit and a ≤, the method note says how it was handled, and it is never quietly turned into a zero that pulls a contour through it. Type in the standard you are being measured against — an MCL, a state standard, a screening level — and it is drawn as a named, emphasised isoline, which is what several state guidance documents actually require.

Drop a CSV or an Excel file of your wells here

One row per well, with coordinates and whatever you want mapped. It is read in this tab and never uploaded.

A made-up site: fourteen wells sampled on 2026-03-14, on a local grid in metres. Two of the benzene results are non-detects reported as <0.5 — they are contoured at their reporting limit, posted with the qualifier, and the figure says so. Type your own standard in and it is drawn as a named isoline.

Or paste the rows

Copy a block straight out of a spreadsheet — tabs, commas and semicolons all work, and you do not have to tell us which. A workbook you dropped appears here as text; editing it re-reads it as text.

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