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Glossary

Definitions of the domain terms and acronyms used across the Erde documentation. Each term is an anchor other pages link to on first use. Capitalization follows the product's own usage: a capitalized term means the specific Erde object or area.

Activity Hub​

The Activity Hub is the internal-user area that gathers activity across your data — the data Audit Log, Comments, and Notifications — alongside the per-record Activity Timeline. It is separate from the Administrator-only System Audit Log. See Activity Hub.

Activity Timeline​

The Activity Timeline is a per-record panel that merges a record's change history and its Comments into one chronological view, newest first. You open it from a record; its tabs filter to all activity, comments, or change history alone. See Activity timeline.

Aggregate​

An aggregate is a cluster of related entities that Erde saves, loads, locks, and audits as one unit, identified by its aggregate root. Children attach to a root exactly once and cannot move between aggregates. See Core Concepts.

Aggregate root​

The top-level entity that owns an aggregate and gives it identity. A root's AggregateExternalId equals its own External ID, and its Concurrency version is bumped whenever any descendant changes, so two callers cannot edit the same aggregate without a conflict. See Aggregates, locking, and auditing.

Analyte​

An Analyte is a substance the lab measures — for example a metal, a volatile organic compound, or a PFAS compound. Analytes are reference data: each carries a name, optional CAS number, and aliases that labs use for the same substance. See Reference data.

Application database​

The Application database (erde_app) holds the domain data — Sites, Locations, Samples, lab results, monitoring readings, and the change Audit Log. It is one of two databases per deployment; the other is the Platform database. See Deployment.

Archive​

A Sample held in reserve rather than analyzed straight away. Archive custody (Archived or Disposed) is tracked separately from the sample's status, so a sample can be collected, analyzed, and archived independently. See Samples.

Basis​

Basis is the reporting basis of a lab result's value — As Received (AR), Wet Weight (W), Dry Weight (D), or Lipid Weight (L). Dry Weight normalizes a solid result to its dry mass, removing the sample's moisture so results compare across samples of differing wetness; Lipid Weight normalizes a tissue result to its fat content; As Received and Wet Weight are the same uncorrected measurement worded two ways. Basis lives on the result, so one analysis can report the same analyte on more than one basis.

Because a dry-weight and a wet-weight value are expressed against different denominators, the analysis tools never blend them: result uniqueness and analysis columns count basis as dry vs lipid vs non-dry (AR and W share the non-dry slot), so a Crosstab gives dry- and lipid-weight results their own columns and a summation rule produces a separate sum per basis. See Lab data reference.

Batch​

A Batch is a laboratory's processing group — the set of samples the lab prepared, leached, or analyzed together — identified by its code and batch type (Preparation, Leach, or Analysis) within a Lab Report, and used to associate analyses with the QC run alongside them. Each Lab Analysis holds at most one batch of each type. See Manage lab batches.

Borehole​

A Borehole is one of the four field artifacts that can exist at a Location, representing drilled or bored subsurface collection. It records lithology intervals, groundwater observations, and sampling runs. A Borehole and a Well may coexist at the same Location. See Sites & Locations.

Chain of Custody (CoC)​

A Chain of Custody (CoC) is the project-scoped record documenting which Samples were transferred to a laboratory and when. A Sample can ride multiple CoCs to different labs, linked through the CoC rather than from the Sample. See Sampling & Chain of Custody.

Code​

A Code is the short, unique identifier you assign to a record — for example a Location MW-01 or a Lab Report LR-2026-001. Erde matches and links records by Code; the record's Name is a non-unique display label. Reference data inverts this, keying on a required, unique Name. A Code accepts letters, digits, and ., -, _ (Measurement Unit codes also allow / and %). See Codes and names.

Comment​

A Comment is a threaded note a user attaches to an aggregate — a discussion thread with replies, @-mentions, priority, and an edit history. Comments are user-generated content kept outside the regulatory Audit Log. See Comments.

Concurrency version​

The Concurrency version is an integer optimistic-concurrency token on every entity. Erde auto-increments it on each modification (and on the aggregate root when a descendant changes), so a save based on stale data is rejected. See Aggregates, locking, and auditing.

Contact​

A Contact is a person belonging to an Organization — name, title, email, and phone numbers. One Contact per Organization can be marked primary, and Contacts can be associated with Projects and Sites. See Contacts.

Crosstab​

Crosstab is a Data Analysis tool that pivots lab results into a sample-by-analyte table, with Screening Criteria Set comparison applied to highlight exceedances. See Data Analysis & Screening.

Data Explorer​

Data Explorer is a Data Analysis tool for querying and exploring your data ad hoc, including options to include or exclude lab-QC data, validator-rejected results, and Tentatively Identified Compound (TIC) results. See Data Analysis & Screening.

Data Management Plan (DMP)​

A Data Management Plan (DMP) is a configuration record a Project can be assigned to, capturing the project's data-handling conventions. A Project carries an optional DataManagementPlanId. See Data Analysis & Screening.

Data Steward​

Data Steward describes the access granted by the RequireDataSteward policy, held by the Administrator and Data Manager global roles. Data Stewards curate reference data, screening programs, and Data Management Plans. See Users, roles, and permissions.

Document​

A Document is a file attached to a record — a report, photo, form, or other file — together with metadata such as an optional category and dates. A Document belongs to a Site or a Project and is classified by the records it relates to: it can be linked to specific Locations, Samples, Lab Reports, and other entities. See Documents.

EMPC​

EMPC (Estimated Maximum Possible Concentration) is a lab-reported estimate for a detected-but-tentative signal — a peak the lab quantified but could not firmly identify, common in EPA dioxin/furan GC-HRMS methods (1613B, 8290A). A Lab Result can carry an EMPC value alongside — or instead of — its result value. In analysis, a detected result that has an EMPC but no result value substitutes the EMPC as its effective value everywhere (screening, charting, summation, and cell display); a non-detect carrying an EMPC can have it stand in as the limit, and a configured DMP can let it supersede the MDL/MRL outright. A validation override always wins over any EMPC substitution. See EMPC handling.

Equipment​

Equipment is a tracked piece of field gear — identified by a unique code, classified by an equipment type, and optionally carrying asset tag, serial number, manufacturer, and model. A Field Parameter Session can record the Equipment used. See Equipment.

External ID​

The External ID is the client-facing identifier (ExternalId) exposed in the API and URLs as a UUID v7 (time-ordered) Guid. Erde keeps an internal integer Id for database use that is never exposed. See Core Concepts.

Field Parameter​

A Field Parameter is an in-situ measurement taken with a probe — such as pH, dissolved oxygen, ORP, specific conductance, temperature, or turbidity — recorded in a Field Parameter Session at a Location. See Field Monitoring.

Field Parameter Session​

A Field Parameter Session is an in-situ measurement event at a Location, holding the readings taken during it and optionally tied to a Well and the Equipment used. It is one of the four monitoring record types, site- and project-scoped. See Field Monitoring.

Fraction​

Fraction is the analytical fraction of the sample a Lab Result represents — for example Total, Dissolved, or Total Recoverable — recorded on the result and on each Screening Level. It is part of both result and screening-level identity, so one analyte can carry a distinct value and a distinct limit per fraction. Matching is exact — Total and Total Recoverable never cross-match — so across the analysis tools each fraction takes its own Crosstab column, a summation rule can restrict itself to a single fraction, and a screening level set to Any applies to every fraction while one set to a specific fraction applies only to that. See Screening.

Hydrograph​

A Hydrograph is a Data Analysis chart that plots groundwater levels over time, built from Water Level readings. See Data Analysis & Screening.

Import​

An Import brings external data — Locations, Samples, lab reports — into Erde through a staged, reviewable pipeline. The commit runs asynchronously and is reversible: a rolled-back Import deletes the rows it created. See Importing Data.

Lab Analysis​

A Lab Analysis is a single analytical run for a Sample or lab QC sample, using a defined Method. It anchors to a Sample, a lab report sample, or both, and contains one or more Lab Results. See Laboratory Data.

Lab Analysis Code​

The laboratory's own identifier for a single Lab Analysis run (its LIMS test or run id), recorded for cross-reference with the lab. Optional and unique within a lab report; it is reference information only and is never used to match Lab Results to analyses on import.

Lab Report​

A Lab Report is the project-scoped record of a laboratory submission, grouping its Lab Analyses and Batches. Its status moves through Draft, Preliminary, Approved, Rejected, and Validated (Validated requires Approved). See Laboratory Data.

Lab Result​

A Lab Result is one measured value within a Lab Analysis: a numeric ResultValue or text result for an Analyte, with its unit, qualifier, and detection limits. See Laboratory Data.

Lab Result Validation​

A Lab Result Validation is the data validator's review of a single Lab Result, held as a separate record so the lab's reported facts stay distinct from the validator's opinions. It carries a validated qualifier, reason code, overridden values, and a validation level. The result's disposition — rejected, estimated, and so on — is derived from the validated qualifier through the Qualifiers reference data, not stored on the validation. Its presence marks a result as validated; its absence means untouched by the validator. See Laboratory Data.

Laboratory​

A Laboratory is an Organization designated as an analytical testing lab — the entity that receives Samples via a Chain of Custody (CoC) and returns Lab Reports. See Laboratories.

Location​

A Location is a sampling or monitoring point within a Site, unique by code within that Site. Each Location can carry field artifacts (Well, Borehole, Test Pit, Sediment Core) and field-monitoring readings. See Sites & Locations.

Logger Channel​

A Logger Channel is one measured series within a Logger Stream — what it records (a monitored Parameter) and the unit it records in. A stream holds one or more channels, and each Logger Reading points at the channel that carries its parameter and unit. See Continuous loggers.

Logger Reading​

A Logger Reading is a single timestamped value recorded on a Logger Channel. Readings are high-frequency telemetry: each carries a ReadingTimestamp, an optional Value, and a per-channel invalid flag and qualifier for quality control. See Continuous loggers.

Logger Stream​

A Logger Stream is a continuous datalogger record attached to a Location, capturing one or more Logger Channels over a deployment window. It may also reference a Well at that Location, and its high-volume Logger Readings are reached through its channels rather than held on the stream. See Continuous loggers.

Matrix​

A Matrix is the sample medium — for example Groundwater, Surface Water, Soil, or Soil Gas — and is reference data referenced by Samples and screening levels. Each Matrix also carries a matrix-type classification (Aqueous, Solid, Gaseous, Biota, and others). See Reference data.

Method​

A Method is a laboratory analysis, preparation, or leachate procedure, held as reference data and referenced by a Lab Analysis. See Reference data.

Non-detect​

A Non-detect is a Lab Result the lab did not detect at or above its reporting limit, marked by DetectedResult = No. Analysis tools can substitute the method detection limit (MDL) or method reporting limit (MRL) for non-detects when screening or charting; a non-detect that carries no limit at all but has an EMPC falls back to it, and a DMP can be set to let the EMPC elevate the chosen limit when the EMPC is higher. See Laboratory Data.

Notification​

A Notification alerts a user to an event relevant to them — an Import they started that finished or failed, an @-mention in a Comment, or a reply to their comment. Each carries a severity and an unread state, and can also be delivered by email. See Notifications.

Operable Unit (OU)​

An Operable Unit (OU) is a default Site Area type — a discrete portion of a site addressed as a single remediation phase. It is one of several seeded site-area classifications (alongside Area of Concern, Source Area, and Plume), not a separate object. See Sites & Locations.

Organization​

An Organization is a company or agency Erde tracks — a lab, consultant, contractor, regulator, or client — classified by an organization type and holding address and contact details. It owns its Contacts; an Organization typed as a lab can be designated a Laboratory. See Organizations.

Platform database​

The Platform database (erde_platform) holds tenant and identity data — users, roles, system settings, application-database registrations, and the System Audit Log. It is one of two databases per deployment; the other is the Application database. See Deployment.

Program​

A Program is a top-level grouping of Projects — it links to Projects only, never directly to Sites. Sites relate to a Program transitively, through the Projects assigned to it. See Sites and Projects.

Project​

A Project is the work scope — a unit of work that owns Samples, Lab Reports, and Chains of Custody, and can link to one or more Sites. Locking a Project freezes all writes to its scoped data. See Sites and Projects.

Qualifier​

A Qualifier is the reference data that defines a lab-result qualifier code (J, U, R, UJ, and the like) and what it conveys — its disposition (estimated, rejected, tentatively identified, biased) and the propagation ranks that decide which code wins when results combine. A result's disposition is derived from its validated qualifier through this catalog. See Qualifiers.

Reference data​

Reference data is the shared lookup lists behind every picker — Matrices, Analytes, Methods, Units, Site Types, and more. Each value has a required, unique Name and a unique Code — optional for most types, but required where the Code is the operational identifier (Methods, Units, Matrices, Detection Limit Types); a value in use cannot be deleted. See Reference data.

Reportable result​

Reportable result is the Yes/No flag on every lab result marking whether the value belongs to the reportable data set. It is part of result identity — a reportable and a non-reportable sibling of the same analyte coexist on one analysis — and the analysis tools read only reportable rows. A validator can override the flag during validation, and the override wins. See Lab analyses and results.

Sample​

A Sample is a physical sample collected for a Project, optionally anchored to a Location, with a Matrix and a sample type such as Normal (N), Field Duplicate (FD), Split (SP), Trip Blank (TB), Equipment Rinsate Blank (ERB), or Field Blank (FB). See Sampling & Chain of Custody.

Screening Criteria Set​

A Screening Criteria Set is a named, versioned collection of screening levels (thresholds) within a Screening Program, against which Lab Results are compared to flag exceedances. See Data Analysis & Screening.

Screening Program​

A Screening Program is a named, code-identified container for one or more Screening Criteria Sets — for example a regulatory standard such as a state cleanup program. It groups the threshold sets that Lab Results are screened against. See Data Analysis & Screening.

Sediment Core​

A Sediment Core is one of the four field artifacts at a Location, representing simple push or drop collection methods (vibracore, box, gravity, or piston). A Sediment Core requires an exclusive Location — no other artifact may share it. See Sites & Locations.

Site​

A Site is the spatial scope — a physical place under management that contains Locations. It carries its own coordinate and boundary geometry and a working coordinate system. Locking a Site freezes all writes to its scoped data. See Sites and Projects.

Site Area​

A Site Area is a named sub-region of a Site — such as an Operable Unit, source area, or plume — with a classifying site-area type, a status, an optional boundary polygon, and a display color. See Sites & Locations.

Test Pit​

A Test Pit is one of the four field artifacts at a Location, recording lithology intervals and groundwater observations from an excavated pit. A Test Pit requires an exclusive Location — no other artifact may share it. See Sites & Locations.

Unit Conversion​

A Unit Conversion is a reference data factor-and-offset that converts a measurement unit to the canonical unit of its compatibility group, letting Erde compare Lab Results reported in different units against the same screening level. See Reference data.

Water Level​

A Water Level is a static (routine) groundwater gauging reading at a Location, optionally tied to a Well. Pumping and recovery readings belong to a Well Purge, not a Water Level. See Field Monitoring.

Well​

A Well is one of the four field artifacts at a Location, recording casing and annular intervals and, optionally, the Borehole it was completed in. See Sites & Locations.

Well Purge​

A Well Purge is a record of water purged from a Well before sampling — low-flow micropurge, conventional volume-based purge, or low-yield purge-and-recover. A row exists only when water was actually purged. See Field Monitoring.