Samples
A Sample is a physical specimen — a jar of soil, a vial of groundwater, an air canister — that your team collects in the field. In Erde, every Sample is owned by a Project and, when it is a field sample, collected at a Location. Each Sample is classified by a Matrix (the medium sampled) and a sample type (the role it plays, including field quality-control roles). Samples are the bridge between fieldwork and the lab: a Sample is what a Lab Analysis measures.
What a Sample is made of
A Sample is an aggregate root — its own top-level record with its own audit trail. Writes to a Sample are frozen when its Project or Site is locked. Three things anchor it:
- A Project owns it. You always create Samples inside a Project, from Data Management → Projects → [your project] → Samples. The Project is taken from where you are, not chosen on the form.
- A Location is where it was collected. A Location is required for field samples and forbidden for trip blanks (which live in coolers, not in the field). The Site comes from that Location and is fixed once the Sample exists.
- A Matrix and a sample type classify it. The Matrix says what was sampled; the sample type says why — a routine sample, a duplicate, or a field blank.
Figure: A Sample is owned by a Project, collected at a Location, classified by a Matrix, and measured by one or more Lab Analyses.
The Matrix
The Matrix is the medium that was sampled. It is reference data you manage, not a fixed list — you add, rename, and deactivate Matrix records to fit your program. Each Matrix carries a Matrix Type that groups it into a broad class. The Matrix Type is a fixed set of six values:
| Matrix Type | Examples you might define |
|---|---|
Aqueous | Groundwater, surface water, wastewater |
Solid | Soil, sediment, rock |
Gaseous | Air, soil gas, indoor air |
SemiSolid | Waste |
Biota | Tissue, vegetation |
NonAqueousLiquid | Product, NAPL |
Erde ships a starter list of Matrix records (Groundwater, Soil, Air, and more) that an administrator can load after install from Reference Data → Matrices, or all at once from Administration → Reference Data Defaults. Matrix is required on every Sample, and you cannot select an inactive Matrix — except to keep the one a Sample already uses. See managing reference data for how to maintain the list.
Sample types
The Sample Type records the role a Sample plays. Every type falls into one of two categories: a field sample or a field quality-control (QC) sample. The category drives the rules — only field samples may carry coordinates, elevation, and a depth interval. The Create Sample form requires you to pick a type; an import that omits one records Normal.
| Sample Type | Code | Category | Meaning |
|---|---|---|---|
| Normal | N | Field | A routine collected specimen |
| Field Duplicate | FD | Field | A second sample taken alongside the parent for precision QC |
| Split | SP | Field | One specimen split between two labs for comparison |
| Trip Blank | TB | Field QC | Travels with the cooler; has no Location |
| Equipment Rinsate Blank | ERB | Field QC | Rinse of sampling equipment, checks cleaning |
| Field Blank | FB | Field QC | Clean medium exposed in the field |
These are field and field-QC types only. Lab quality-control concepts — method blanks, laboratory control samples, matrix spikes — are not Sample types; they live with Lab Analyses, not field Samples.
The sample code
The Code is the Sample's identifier — for example MW-01-20260613. It is required, up to 50 characters, and may contain only letters, numbers, periods, hyphens, and underscores; spaces and other special characters are rejected.
Erde normalizes the Code on save: it trims surrounding whitespace and preserves the case you typed. Codes are matched case-insensitively in the database, so mw-01 and MW-01 are treated as the same value. A Code is unique per Project and date — the triple (Project, Code, Sample Date) — so the same Code may legitimately recur on a different Sample Date.
Status
A Sample moves through a small set of states. When you do not set a status, Erde defaults it from the Sample Date: a past-or-today date becomes Collected, while a missing or future date becomes Planned.
| Status | Meaning |
|---|---|
| Planned | Scheduled but not yet collected |
| Collected | Physically collected; requires a Sample Date |
| Voided | Cancelled or invalidated |
Whether a Sample has been analyzed is not a status. The Samples grid shows an Analyzed indicator that Erde derives from whether any Lab Analysis references the Sample, so it stays correct as analyses are added or removed.
Archives
An archive is a portion of a Sample held in reserve — in house, at the lab, or elsewhere — rather than analyzed straight away. Archive custody is a separate field from Status, so a Sample can be, say, Collected and archived at the same time, and an archive that is later pulled and analyzed keeps its status while the Analyzed indicator lights up.
| Archive status | Meaning |
|---|---|
| (none) | Not an archive |
| Archived | Held in reserve |
| Disposed | The hold has ended and the sample was discarded |
To plan an archive before collection, leave Status as Planned and set the archive to Archived. Marking a Sample as an archive, or voiding one, after lab analyses already reference it is unusual — Erde warns but still lets you save so you can tidy records.
Parent samples
A field duplicate references the original it was taken from by Parent Sample Code and Parent Sample Date — plain text values you fill in (or pick to pre-fill), not a hard link. If the parent Code is not found, Erde warns you but still saves; it blocks only when a Code is ambiguous (several Samples share it and you gave no date to tell them apart). A Sample cannot be its own parent, and you cannot delete a Sample that still has dependents — child samples that name it as parent, Lab Analyses, or Chain of Custody links.
Field reference
Beyond the Code, Matrix, sample type, status, and archive covered above, a Sample carries the collection detail below. The spatial fields (coordinates, Coordinate System, Elevation, Elevation Unit, Vertical Datum) are allowed only on field samples; on a field-QC sample they are rejected.
| Field | Type | Required | Notes |
|---|---|---|---|
| Name | text | No | Human-readable label; up to 100 characters |
| Composite Sample | yes/no | No | Marks a sample pooled over a window; warns if you set it without a Sample End Date |
| Weather Conditions | text | No | Field conditions; up to 500 characters |
| Sample Method | reference | No | The sampling method used; managed reference data |
| Project Task | reference | No | The Project task this sample belongs to |
| Coordinate System | reference | No | The system the coordinates are in; field samples only, and only with coordinates |
| Elevation | number | No | Ground or measuring-point elevation; field samples only |
| Elevation Unit | ft / m | No | Unit for Elevation; field samples only |
| Vertical Datum | reference | No | The datum the elevation is referenced to; field samples only, and only with an Elevation |
How it fits together
| Aspect | Field sample | Field-QC sample |
|---|---|---|
| Category | Field | FieldQC |
| Location | Required | Optional; not allowed for trip blanks |
| Coordinates, elevation, depth | Allowed | Not allowed |
| Typical types | Normal, Field Duplicate, Split | Trip Blank, Equipment Rinsate Blank, Field Blank |
A Sample sits between the field and the lab. Locations belong to a Site; the Project draws on the Sites linked to it. Once samples reach the laboratory, each is measured by one or more Lab Analyses, whose results carry the data you screen and report.
Related
- Record a sample — create and edit Samples in a Project.
- The Erde data model — how Samples relate to Sites, Projects, and lab data.
- Sites & Locations — where field samples are collected.
- Lab analyses and results — how samples are measured.
- Glossary — definitions of Erde terms.