Frequently Asked Questions
What is OpenSurvey3D?
OpenSurvey3D is a free, MIT-licensed field app for iPhone and iPad. It collects points, lines, areas, routes, media, and georeferenced 3D captures; connects to external GNSS and NTRIP corrections; supports stakeout, check shots, and COGO; exports open project files; and can share a project as a web map link.
Is it really free and open source?
Yes. The app is free, has no required account or subscription, and the native Swift code is published on GitHub under the MIT license. OpenSurvey3D's name and logo remain Laan Labs trademarks, but the code can be inspected, built, and adapted under the license.
Do I need an RTK receiver?
No. The full project and collection workflow runs on the iPhone or iPad location service, typically at roughly 3–5 meter accuracy. That is useful for reconnaissance, inventories, and sketch mapping. An external GNSS or RTK receiver brings the same workflow to sub-meter or centimeter-class work.
Which GNSS receivers work?
OpenSurvey3D connects to Emlid Reach RX, RX2, and RS4 and Bad Elf Flex and Flex Mini receivers over Bluetooth, to Leica Zeno GG04 plus and FLX100 plus antennas through Leica's Zeno Connect app, and to any receiver that streams NMEA 0183 over a Wi-Fi TCP connection. The TCP path covers hotspot or shared-network workflows used by Emlid RS2/RS2+, Eos, ArduSimple-class, and similar rovers. See the connection guides for each.
Does it include an NTRIP client?
Yes. The app includes saved caster profiles, secure password storage, NTRIP v1/v2 handling, source-table and mountpoint browsing, a directory with list and map views, RTCM forwarding to the connected rover, correction health, and automatic reconnect.
Does it work offline?
Yes. Projects, assets, observations, photos, scans, and generated site models are local to the device. You can download the current 2D map area in advance, and built 3D terrain and imagery stay cached. A network connection is still needed when first downloading map, terrain, or correction data.
What can I import and export?
Import points, lines, routes, and areas from CSV, PNEZD, GeoJSON, DXF, LandXML (including curved road alignments), GeoPackage, zipped Shapefile, GPX, and KML, including projected northing/easting in the project's zone. Export CSV, PNEZD, GeoJSON, DXF R12, LandXML 1.2, GeoPackage and Shapefile in your state plane zone, LAS point clouds, ground-scaled point files, DXF and LandXML, a complete project ZIP, QA reports as PDF or HTML, closure sheets, and terrain geometry as OBJ.
What 3D capture does the app support?
OpenSurvey3D has LiDAR point-cloud and photogrammetry capture paths, plus ordinary photos and video. Mesh scanning is paused while it moves to a new capture engine; earlier mesh scans still open. Captures can be anchored to a surveyed asset and observation, viewed in the project, included in QA, and combined with terrain, imagery, routes, and points in a 3D site model. Device capabilities vary; point-cloud capture requires LiDAR hardware.
How does AR asset finding work?
Choose Find in AR from an asset or open a browsed project to see its nearby assets through the camera. OpenSurvey3D converts stored project coordinates into local AR pins and shows target direction, bearing, and distance for assets within 250 metres. The view inherits current GNSS and compass uncertainty, so it is designed to reach an asset's vicinity. Use numeric stakeout and check shots when a position must be set or accepted.
How does field QA work?
Every observation keeps its positioning pedigree and receiver health. For independent verification, re-observe an imported design point or collected control point. The app records northing, easting, and vertical residuals, tolerance and pass/fail, and project RMS, then produces a report with checks, estimates, solution health, captures, and exceptions.
Which coordinate systems are supported?
Projects can use WGS 84 or select from 325 NAD83 State Plane and worldwide UTM entries. Projected imports and exports carry easting, northing, units, and EPSG identity where available. The app keeps geographic and projected coordinates together instead of discarding one representation. On a NAD83 project, fixes from ITRF / WGS 84 corrections are shifted into NAD83(2011), and NAVD88 elevations can come from GEOID18 grids downloaded in the app.
Does it support ground coordinates?
Yes. Every point shows its grid scale factor, elevation factor, and combined factor, and the CSV carries them beside northing and easting. A ground coordinates export writes a ground-scaled point file, CSV, DXF, and LandXML using the project's mean factor or one you type, about grid 0,0 or a point you choose, with a note stating exactly how it was scaled. Line and typed-coordinate stakeout work on grid or ground.
Can it stake out lines and typed coordinates?
Yes. Stake to any line or boundary and read station and offset live (for example Sta 3+50.00, 10.00 ft R), or type a station and offset and walk to it, with cut or fill at the rod from a design surface. You can also key a northing and easting off a plat and walk straight to it. Stakeout tolerances can be typed down to 0.01 ft.
Can I share a project with someone who doesn't have the app?
Yes. Share online makes a link that opens the project on a map in any browser, with positions in latitude/longitude and your state plane grid, accuracy, elevations, attributes, photos at 1024 px with their location data removed, and closure sheets, plus CSV and GeoJSON downloads. No account is needed on either side. You can update the link, stop sharing at any time, and every link is deleted 90 days after its last update. The operator name is left off unless you switch it on.
Can I keep shared projects on my own server?
Yes. The share server is on GitHub as opensurvey3d-cloud, with a Docker Compose setup for a machine you control. Point the app at it under Settings → Share server, and new links are made there.
Is the browser workspace available?
Not as a workspace. Share online gives anyone a read-only web map of a project, but editing and syncing projects in the browser remains on the roadmap. The native iPhone/iPad app, local projects, open-source repository, and file-based handoff are available now.
Is this a replacement for a licensed surveyor?
No. OpenSurvey3D is a measurement and documentation tool. Boundary determination and many survey deliverables legally require a licensed professional. The app preserves measurement context and quality evidence; it does not make professional or legal judgments.