Analyse and Map Your Scan
This page covers all the filter and gridding settings in PolarWave Data that let you extract the most detail from your FGA Logger survey — from adjusting the 3D model's appearance to fine-tuning the colour map overlay.
New to PolarWave Data? Start with Visualise Your Survey Data to upload your scan first.
Channel and Filter Scope
At the top of the right-hand panel you can control which channels are processed and which filters are applied.
Channels
The FGA Logger records up to 12 channels across two sensors. Toggle individual channels on or off to focus the analysis:
| Button | Action |
|---|---|
| All | Enables all recorded channels |
| None | Deselects all channels |
| Channel tag (×) | Click to remove a channel from the current view |
Filter Scope
| Setting | Description |
|---|---|
| Apply to | One channel applies the filter only to the selected target channel; All channels applies it to every active channel simultaneously |
| Target channel | Selects which channel the filter acts on when One channel is chosen |
FGA Logger Settings
| Setting | Description |
|---|---|
| Sensor Distance, m | The physical distance between the two fluxgate sensors in metres. This value is used to calculate the gradient — the rate of change of the magnetic field between the two sensors. Set this to match your actual sensor separation for accurate depth estimates |
The gradient (Gx / Gy / Gz / Gv channels) is computed as the difference between Sensor 1 and Sensor 2 divided by the sensor distance. An incorrect distance value will scale the gradient incorrectly.
3D Model Filters
The right-hand panel contains filters that control how the data is displayed. These are useful for bringing out subtle anomalies.
Common Settings
| Setting | Description |
|---|---|
| Enable top plane | Toggles a flat reference plane across the top of the 3D model — useful for visualising how deep anomalies sit below the surface |
| Show Axis | Displays X/Y/Z axis markers in the 3D view for orientation |
| Show Real Values | When checked, the colour scale shows actual measured values; uncheck to see normalised values instead |
| Walls transparency % | Controls how transparent the side walls of the 3D surface box are. 10% means nearly opaque — increase this if the walls are obscuring the model |
Amplify / Smooth
| Setting | Description |
|---|---|
| Coefficient | Scales the vertical (Z) exaggeration of the 3D surface. A value of 2 doubles the height of peaks and troughs, making subtle anomalies more visible. Increase it if your scan looks flat; reduce it if spikes are too extreme |
Soil Settings
| Setting | Description |
|---|---|
| Magnet Type | Set to New soil by default; adjust to match your survey ground conditions (e.g. mineralised or ferrous-rich soil), which affects how the signal is interpreted when detecting the buried object depth |
| Metrics | Switches the distance units between Metres and Feet |
| Draw Texture | When enabled, adds a ground texture to the surface render for a more realistic visual appearance |
Decimation
Reduces the number of data points to improve performance while preserving the overall shape of the scan. Useful for large surveys that render slowly.
| Setting | Description |
|---|---|
| Step | Controls how aggressively data is decimated. A value of 10 means every 10th point is kept. Increase to improve performance; decrease to restore detail |
Interpolation
Fills gaps between data points to produce a smoother surface.
| Setting | Description |
|---|---|
| Enabled | Turns interpolation on or off |
| Max value | The maximum distance over which interpolation is applied. Keep this low to avoid filling large gaps with unreliable data |
Averaging
Smooths the data by averaging neighbouring values, reducing noise at the cost of some sharpness.
| Setting | Description |
|---|---|
| Enabled | Turns averaging on or off |
| Size | The number of neighbouring points included in the average. Larger values produce a smoother but less detailed result |
Median Filter
Removes spikes and outliers by replacing each value with the median of its neighbours. More aggressive than averaging for eliminating isolated noise.
| Setting | Description |
|---|---|
| Enabled | Turns the median filter on or off |
| Size | The neighbourhood size used for the median calculation. Increase to remove larger spikes |
Bilateral
Edge-preserving smoothing — reduces noise while keeping sharp boundaries between anomalies intact.
| Setting | Description |
|---|---|
| Enabled | Turns bilateral filtering on or off |
| Sigma | Controls the strength of the filter. Higher values apply stronger smoothing |
Anisotropic
Directional smoothing that follows the structure of the data, preserving anomaly edges better than standard smoothing.
| Setting | Description |
|---|---|
| Enabled | Turns anisotropic filtering on or off |
| Iterations | The number of smoothing passes applied. More iterations produce a smoother result |
Bicubic
Applies bicubic interpolation for a higher-quality surface render with smoother curves between data points.
| Setting | Description |
|---|---|
| Enabled | Turns bicubic interpolation on or off |
Tags
Allows you to place markers on points of interest directly on the 3D model or 1D graph. Tags are useful for flagging anomalies for further investigation.
Map Gridding Settings
These settings appear in the right-hand panel when you are in Maps view.
| Setting | Description |
|---|---|
| Show GPS track | Overlays the actual path you walked during the survey on the map as a line — useful for checking survey coverage and line spacing |
| Enabled | Turns gridding on/off. When on, your raw survey lines are interpolated into a filled colour map. Turn it off to see only the GPS track line |
| Mode | Set to Single channel for a standard single-sensor output, or select the appropriate dual-channel mode when using both sensors |
| Palette | Controls the colour scheme of the grid. Rainbow uses the full spectrum (blue → green → yellow → red) and is good for general use |
| Cell size, m | The resolution of the grid in metres. 0.25 means each grid cell is 25 cm × 25 cm. Smaller values give a sharper map but require tighter line spacing. Increase this if the map looks patchy |
| Blanking, m | Any area further than this distance from a survey line is left blank — prevents the gridding from speculating too far into unsurveyed ground |
| Zero offset data | Removes the DC baseline shift from the data so the colour scale is centred around zero. Leave this checked in most cases |
| Anomaly mode (BiV) | Bi-polar Value mode — emphasises both positive and negative anomalies symmetrically around zero. Useful for highlighting dipole targets such as buried ferrous objects |
| Baseline window | The number of readings used to calculate the rolling baseline for anomaly removal. Increase for surveys with broad regional trends; decrease to be more sensitive to short-wavelength anomalies |
| Min/Max clip | Clamps the colour scale to a set range. Narrow this range to increase contrast and make subtle anomalies more visible. Use Reset clipping to return to the full data range |
Start with the full colour range to get an overview, then gradually narrow the Min/Max clip range until your targets of interest stand out clearly.
Quick Reference
| Step | Action |
|---|---|
| 1 | Export your data file from the FGA Logger (SD card or USB) |
| 2 | Log in to polarwave.app |
| 3 | Go to Survey → Search → Select File → Upload |
| 4 | Click your survey in the Data Library — Explorer view opens by default |
| 5 | Select the channel to analyse (e.g. Gv for total gradient) |
| 6 | Enable Gridding in the right-hand panel to see the colour map |
| 7 | Click 3D View in the left sidebar to explore the 3D surface model |
| 8 | Use right-panel filters to highlight anomalies, then adjust colour scale |
Troubleshooting
Map view shows only a GPS line, no colour data
Cause: Gridding is not enabled.
Fix: Toggle Gridding on in the right-hand panel.
Device type not detected automatically
Cause: The filename was changed or the file header was modified.
Fix: Manually select your FGA Logger model from the Device Type dropdown during upload.
No GPS line appears in Map view
Cause: GPS was not active during the survey, or the file format does not include location data.
Fix: Ensure GPS logging is enabled on the logger before starting your next survey. Check the logger manual for the GPS activation procedure.
Gradient channels show incorrect values
Cause: The Sensor Distance setting does not match the actual physical separation between your two sensors.
Fix: Open the right-hand panel and update Sensor Distance, m to the correct value in metres.
Upload fails or stalls
Cause: Network interruption or unsupported file format.
Fix: Try a different browser, check your internet connection, and confirm the file is in the original exported format from the logger — do not rename or convert it.