Glossary of core logging, geological mapping and sampling

The terms you meet in Field Manager and in the day-to-day of an exploration campaign, defined in a line or two. Each one links to the manual chapter that explains it in full.

Drill holes and core logging

Collar

The mouth of the drill hole: the point where drilling enters the ground. Its record holds the coordinates, azimuth, dip and total depth of the hole. In Field Manager collars live in the drill hole data table and are loaded by importing a CSV, Excel, TAB file or a point shapefile carrying the Hole ID.

Explained in: Import drill hole collars and surveys from CSV or Excel

From / To (interval)

The pair of depths that bounds each described run of the hole: where the observation starts and where it ends. Together with the Hole ID it is the key that links every logging table. The geocoder defaults "From" to the previous interval's "To", so you log continuously with no gaps or overlaps.

Explained in: Lithology, alteration, mineralisation and QA/QC: the logging tables

Hole ID

The unique identifier of the drill hole (for example DDH-001). It is the field that relates lithology, alteration, mineralisation, structure, sampling, geotechnics and photos of one hole, and the one the hole selector uses to filter the whole screen.

Explained in: Lithology, alteration, mineralisation and QA/QC: the logging tables

Core logging

The systematic, interval-by-interval description of drill core: lithology, alteration, mineralisation, structures, geotechnics and sampling. In Field Manager it is done straight on the tablet over the strip log, with no paper sheet in between.

Explained in: How to log drill core on a tablet

RQD

Rock Quality Designation: a geotechnical index of rock mass quality based on the proportion of core pieces longer than 10 cm within an interval. It is recorded in the geotechnics table, alongside core recovery, fracture count and RMR classification.

Explained in: Lithology, alteration, mineralisation and QA/QC: the logging tables

Drill hole

The exploration borehole the core comes from. In the app it is the working unit of the drill hole module: you pick one in the hole selector and the whole screen — strip, tables and charts — is filtered by it.

Explained in: How to log drill core on a tablet

Survey (deviation)

The azimuth and dip measurements taken at successive depths, describing how the hole deviates from its planned straight path. They are imported together with the collars from CSV, Excel or standard formats.

Explained in: Import drill hole collars and surveys from CSV or Excel

Core

The rock cylinder recovered by diamond drilling, described by the geologist at the logging table. It is the physical object behind every observation that later lands in the logging tables.

Explained in: How to log drill core on a tablet

Strip log

The vertical graphic view of the hole: one column per visible layer that has a dynamic style, with the depth ruler alongside. It is the digital equivalent of the hand-drawn logging sheet, and it zooms, scrolls and widens with gestures.

Explained in: How to log drill core on a tablet

Log track

The setting that decides how a layer is drawn inside the strip log: interval (colour blocks per run), symbol, or chart (a numeric value plotted against depth, typically a grade or RQD).

Explained in: How to log drill core on a tablet

Geological description and data quality

Alteration

The set of mineralogical changes the rock underwent through hydrothermal fluids or supergene weathering. It is logged per interval with type and intensity, and is one of the pre-loaded tables of a drill hole project.

Explained in: Lithology, alteration, mineralisation and QA/QC: the logging tables

Lithology

The rock type and lithological unit of each interval, with its written description. It is the base logging table and usually the one driving the main dynamic style of the strip log, with one colour per unit.

Explained in: Lithology, alteration, mineralisation and QA/QC: the logging tables

Mineralisation

The record of ore minerals, their textures and the visual grade estimates per interval. Together with lithology and alteration it forms the trio logged in parallel over the same core run.

Explained in: Lithology, alteration, mineralisation and QA/QC: the logging tables

QA/QC (standards, duplicates and blanks)

The control samples inserted into the sampling stream to check that the lab and the sampling itself are reliable: certified standards, duplicates of the same sample, and blanks of barren material. Field Manager records them in the sampling table, under the same validation rules as everything else.

Explained in: Lithology, alteration, mineralisation and QA/QC: the logging tables

Surface mapping, layers and working offline

Basemap layer (WMS, WMTS, XYZ)

The background imagery the map is drawn over — satellite, topographic, geological — served over the internet through one of those three standard protocols. In Field Manager they sit in their own section of the layer menu and their tiles can be downloaded for later use with no signal.

Explained in: Vector layers, rasters and WMS basemaps in the field

Vector layer

A project table whose rows carry geometry (point, line or polygon): outcrops, contacts, structures, samples. It is the layer type the geologist captures and edits data in; raster and basemap layers are display-only.

Explained in: Vector layers, rasters and WMS basemaps in the field

DEM (digital elevation model)

A raster whose pixel value is terrain elevation. Field Manager uses it to read heights and for the DEM-intersection operation, which gives elevation to the geometries drawn on the map.

Explained in: Vector layers, rasters and WMS basemaps in the field

Offline map

The map area downloaded in advance, by zoom range, to work on campaigns with no coverage. It is what lets surface mapping behave exactly the same 200 km from the nearest town.

Explained in: Download maps for no-signal work, filter and label your data

Layer memory

A slot that stores the state of every map layer — visibility, snap and selectability — to reapply it with one tap. Each map has nine, and they let you jump between a mapping view, a sampling view and a presentation view without reconfiguring anything.

Explained in: Offline geological mapping: map, layers and layer memories

Raster

A georeferenced image layer on a pixel grid: drone orthophoto, satellite imagery, scanned map or DEM. It is loaded into the project and drawn beneath the vector layers.

Explained in: Vector layers, rasters and WMS basemaps in the field

Snap

The magnetic pull of drawing onto existing vertices and edges, so contacts close with no slivers or overlaps. It is enabled per layer, and absolute snap forces the new node to take the exact coordinate of the one it snaps to.

Explained in: Digitising contacts and structures: drawing, GPS and geometry editing

Track (GPS trace)

The continuous log of GPS coordinates while you walk, stored in a special map layer. It keeps recording with the app in the background and is stopped from the system notification.

Explained in: Offline geological mapping: map, layers and layer memories

Data, validation and styles

Dynamic style

The rule that decides the colour, symbol or pattern of each feature from the value of up to three conditioning attributes. It is what turns a table into a thematic map: samples coloured by gold grade, lithologies by unit, structures by type and angle.

Explained in: Dynamic styles: colour samples by grade and lithology by unit

Filter

An SQL condition applied to a layer that leaves only the matching rows visible, both on the map and in the data browser. It is used, for example, to show several lithologies at once with the in operator.

Explained in: Download maps for no-signal work, filter and label your data

Geocoder

The set of rules that validates and assists data entry for a table: which fields are mandatory, which values are accepted, in what order they are asked and with which selector. It is what makes two different geologists capture the same datum the same way. They are defined outside the app, in the spreadsheet support provides.

Explained in: Geocoders: make every geologist log data the same way

Tuple (record)

One row of a project table: a logged interval, a sample, a measured structure. It is the word the app uses throughout its interface for an individual record.

Explained in: Geocoders: make every geologist log data the same way

Coordinates, GPS and interchange formats

GeoTIFF

The standard raster image format that carries its georeferencing inside the file itself. Field Manager imports and exports GeoTIFF, which is how drone orthophotos and DEMs travel between the tablet and desktop software.

Explained in: Export to SHP, TAB, Excel and GeoTIFF (and import into your project)

NMEA

The standard protocol an external GNSS receiver uses to stream its coordinates. Any Bluetooth-paired unit that speaks NMEA can be chosen as the activity's GPS source instead of the tablet's built-in receiver.

Explained in: Preferences: projection, GPS source, stylus and capture accuracy

Projection, SRID and EPSG

The coordinate system map positions are expressed in (WGS84, a UTM zone, and so on). Field Manager identifies them by SRID — the numeric code assigned by the EPSG registry — and defines them in Proj4 format; custom projections can also be created.

Explained in: Preferences: projection, GPS source, stylus and capture accuracy

Shapefile (SHP)

The most widespread vector format in the GIS world. It is one of the standard ways in and out of a project: layers and collars are imported as SHP and logged data is exported to carry on at the desktop, alongside TAB, Excel and CSV.

Explained in: Export to SHP, TAB, Excel and GeoTIFF (and import into your project)