Known limitations

What OpenSurvey3D doesn't do yet — datum shifts it can't make, geoid coverage, ground coordinates, receivers not yet bench-tested, sharing online and more.

On this page

OpenSurvey3D tries to be clear about what it can and can't do. This page lists the gaps that matter most for survey work, so you can plan around them. Many of the same caveats are written into the exports and the QA report.

Coordinates and datums

Datum shifts depend on what you tell the app

A fix is in whatever frame its corrections' base is in, and nothing in the data stream says which. So the app asks: set Corrections are in for each caster (and for Zeno Connect). On a NAD83 project:

  • NAD83(2011) corrections (a state CORS or VRS network such as KYCORS) are used as they come.
  • ITRF / WGS 84 corrections (RTK2go, Emlid Caster, most single bases) are shifted into NAD83(2011) with NGS's published transformation as each fix is taken.
  • Not stated: no shift is applied. The receiver sheet warns, and the QA report flags those fixes.

What the shift leaves out:

  • Crustal motion since 2010.0, which is centimetres a year on the West Coast.
  • Points saved before the shift existed, or saved with the frame unstated. They aren't converted afterwards.
  • Every other pairing, for example ETRS89 corrections on a NAD83 project, or ITRF on a European zone. Those are reported, not shifted.

Write the realization and epoch on your plat yourself. See NTRIP corrections and NAD83 vs ITRF: datums and epochs.

GEOID18 only, and only for the lower 48, Puerto Rico and the USVI

The app can download NGS's GEOID18 grids and compute NAVD88 elevations through them. GEOID18 doesn't cover Alaska, Hawaii or Guam, and other geoid models (GEOID12B, EGM2008) aren't available yet. Elsewhere, elevations above sea level are what your receiver reports.

GEOID18 is only applied to fixes known to be in NAD83(2011): corrections stated as NAD83, or shifted from ITRF. A fix with an unstated frame keeps the receiver's own elevation. See Vertical datum.

Ground coordinates are an output

The app stores and computes everything on the grid. Ground coordinates come out of Tools → Ground coordinates…, a ZIP scaled by one factor that states how it was scaled, and can be keyed when staking a typed coordinate. COGO still takes its entries on the grid, and reports grid and ground side by side.

Site localization is reported, not applied

The app solves a site localization from your check shots and reports its residuals and parameters, but it doesn't apply it. No coordinate in the app or its exports is transformed by it. See Site localization.

Alaska zone 1 is missing

Alaska state plane zone 1 (an oblique Mercator projection) isn't in the list of coordinate systems.

Field work

Line stakeout is plan only

Stake to a line works from a line's plan geometry. A LandXML alignment comes in with its curves, spirals and start station, but its profiles and cross-sections are ignored. For cut and fill at the rod, load a design surface.

No inserting or deleting vertices on a saved line

Once a line or area is saved, you can edit or re-measure an existing vertex, but you can't add or remove vertices.

Averaging has no minimum-epoch setting

An averaged occupation runs until you stop it. There's no setting to require a minimum number of epochs. Watch the sample count and the spread, and stop once they've settled.

Receivers

Bluetooth receivers aren't bench-tested yet

Bluetooth supports two families of receivers: the Emlid Reach RX, RX2 and RS4, and the Bad Elf Flex and Flex Mini. Neither has had a full hardware bench test yet.

  • Sending corrections to a Bad Elf Extreme over Bluetooth hasn't been confirmed. Running NTRIP in the Bad Elf Flex app in the background works regardless.
  • The Emlid Reach RS2 and RS2+ can't stream to third-party iOS apps over Bluetooth. Use their Wi-Fi hotspot instead.

See Connect a Bluetooth receiver.

Leica Zeno goes through Zeno Connect

A Leica Zeno GG04 plus or FLX100 plus streams to the app through Leica's Zeno Connect app, tested with Zeno Connect 4.3. Fix quality, corrections and antenna height haven't had a full bench test yet.

  • Zeno Connect must stay running in the background while you work. If it's closed, positions stop until it's open again; the app reconnects by itself.
  • Corrections run in Zeno Connect. The app can't send corrections to a Zeno antenna. It shows the fix type and correction age Zeno Connect reports.
  • Set the antenna height in one place. It isn't confirmed yet whether a height set in Zeno Connect is applied to the positions it sends, so set it to 0 there and enter the pole height in OpenSurvey3D.
  • Zeno Connect sends each position's accuracy just before the position, so the app takes each epoch when the next one starts: about a second behind.

See Connect a Leica Zeno antenna.

Phone GPS heights are rough

Without a receiver, heights can be 5–15 m off. In the 3D view they snap to the terrain by default. The QA report flags any height with a vertical accuracy worse than 3 m as phone-GPS grade. See Phone GPS vs a receiver.

Sharing online

  • A link is a snapshot. It shows the project as it was at the last Update share, not live.
  • Scans, videos and raw receiver logs aren't shared. Send an export bundle for those.
  • Links expire 90 days after their last update.
  • Anyone with the link can see it. There are no per-person permissions.

See Share a project online.

Maps, 3D and capture

Terrain is public elevation data

The 3D site model uses public elevation models, about 10 m resolution in the US and 30 m elsewhere. Heights are above sea level. In dense cities the data is often a surface model, so buildings appear as blocks. See 3D site model.

Mesh scanning isn't open yet

Mesh scanning is off while it's rebuilt on a new capture engine, so it doesn't appear in the New capture sheet. Mesh scans taken with earlier versions still open and share. Point-cloud capture and photo capture (Object Capture) work on supported devices. See 3D capture overview.

Compass headings on scans

A scan oriented by the phone's compass can be 10–20° off in the open, and worse near metal. At working range that's metres of error. Walking a few metres during capture lets the heading come from the GNSS track instead.

Import

  • Polygon holes aren't imported; only outer rings come in.
  • KMZ files aren't read; use plain KML.
  • A headerless point file with numeric point numbers needs a header row. See Import.