Frequently asked questions
FieldToCAD is a client-side survey coordinate transformation tool. Your survey coordinates are never uploaded. Only optional account metadata (localization presets, billing) touches the cloud.
- Does FieldToCAD upload my survey coordinates?
- No. Parsing, localization, projection, and visualization run entirely in your browser. Survey coordinates are read from your file into browser memory and never sent to our servers. Optional cloud features (saved localization presets and billing) store only metadata, not coordinates.
- What file formats does FieldToCAD support?
- FieldToCAD supports Trimble JobXML (.jxl), Carlson RW5 (.rw5), Trimble RXL (.rxl), and point-list CSV/TSV imports. Binary formats like .job and .dc are not supported. Export a text-based file from your data collector instead.
- How does ground-to-grid localization work?
- FieldToCAD applies a 4-parameter 2D conformal (similarity) transform: scale, rotation, and east/north shifts. This is the standard Helmert localization used by survey crews to reconcile a localized ground grid with an official coordinate reference system.
- What is a combined scale factor (CSF)?
- The combined scale factor is the product of the grid scale factor (from your State Plane or UTM projection) and the elevation factor (from your project height above the ellipsoid). It is the scale value s in your localization that reconciles ground distances with grid coordinates.
- Does FieldToCAD support SPCS2022 and NATRF2022?
- Yes, as a clearly labeled preliminary reference only. SPCS2022 and NATRF2022 are NGS preliminary products as of 2026 and are not yet officially adopted, so production export is disabled until final definitions and transformations are implemented.
- What coordinate systems (zones) are available?
- FieldToCAD ships with 122 official NAD83(2011) SPCS zones whose projection methods are implemented natively (Lambert Conformal Conic 2SP and Transverse Mercator), NAD83 UTM 13N, WGS84 UTM zones 1N-60N and 1S-60S, and one clearly labeled SPCS2022 preliminary reference zone. Alaska Zone 1 / EPSG:6394 and other Hotine/Albers/specialized CRS are blocked until the PROJ-WASM engine is verified.
- Can I export to Civil 3D?
- Yes. FieldToCAD exports LandXML (.xml), the primary interchange format for Autodesk Civil 3D survey points and observations. A secondary Field Book (.fbk) export is also available for Survey Command Language workflows.
- What is the difference between free and Pro?
- Free includes parsing, localization, transformation, visual validation, and local export. Pro ($79/month or $699/year) unlocks server-enforced production export with entitlement verification. All iterative survey work stays on your device either way.
- Why does FieldToCAD need geoid separation for CSF?
- The elevation factor in combined scale factor reduction requires ellipsoid height (h = orthometric elevation H + geoid separation N). Using orthometric height alone introduces up to ~5 ppm error in CONUS. FieldToCAD auto-fills N from bundled NGS GEOID18 grids for CONUS, Puerto Rico, and the U.S. Virgin Islands, with manual entry still available outside coverage.
- Does FieldToCAD handle JobXML Reductions correctly?
- Yes. Trimble JobXML Reductions already include prism constant, station scale factor, and sea-level corrections. FieldToCAD reads Reductions when present and never double-applies corrections, a common parser trap.
- Is FieldToCAD a substitute for a licensed surveyor?
- No. FieldToCAD is an analytical data-processing utility. Final geodetic validation and statutory sign-off remain the responsibility of the Licensed Professional Land Surveyor.
- Does FieldToCAD work offline?
- Yes. With no Supabase configuration, the app runs in fully offline free local mode. All computation is local. Jobs persist via OPFS and IndexedDB on your device.
- What datums does FieldToCAD use?
- Production defaults to NAD83(2011) on the GRS80 ellipsoid with NAVD88 orthometric heights. Preliminary NATRF2022/SPCS2022 zones are labeled reference-only and cannot be exported as production output.
- How accurate are the projections?
- Transverse Mercator uses the Krueger 6th-order series (Karney 2011), accurate to roughly 5 nm within 35 degrees of the central meridian. Lambert Conformal Conic follows Snyder with EPSG-verified NAD83(2011) zone parameters.
- What is Active Armor?
- Active Armor is FieldToCAD's fail-closed geographic guard for already-reduced grid coordinates. It inverse-projects the coordinate centroid back to latitude/longitude through the matched zone's projection and checks it against a per-zone guard envelope, rescaling units first so a metric-vs-foot mismatch can't false-pass. The same check runs on the target zone using the localized centroid. If either lands outside its envelope, or a localization would double-scale coordinates that are already on the grid, export and the combined scale factor stay locked in Inspect Only until you confirm the source and target CRS. The check runs entirely in your browser.
- Can I save localization presets?
- Yes, with a signed-in account. Presets store scale, rotation, shifts, and target zone. Coordinates are never stored. They sync via Supabase with row-level security (owner-only access).