Before the first import

Data sources

GeoBridge does not download data from the internet — all source data must be present as files. Typical sources for Germany:

For a first test without your own data, free sample tiles from Thuringia are available on request — see Help & Support.

What "georeferencing" means in Revit

Revit has three anchor points:

• Internal Origin (IO) — the immutable internal zero of the file.
• Project Base Point (PBP) — the user-facing project origin. Defaults to IO but can be moved.
• Survey Point (SP) — the georeferenced anchor. Carries real-world coordinates and ties the model into a coordinate reference system.

On the first import, GeoBridge writes the Survey Point. On every later import, the new data automatically docks onto the existing Survey Point without asking again. This is how DOP, DGM, and CityGML stack up congruently.

What happens on the first import?

The import dialog has four sections:

1. Source CRS — the EPSG code of the file's coordinate reference system. GeoBridge reads it from the file or asks.
2. UTM convention — see next section; only relevant for ETRS89/UTM data.
3. Anchor variant — where should the Survey Point be placed?
4. Preview — shows the computed coordinates and the resulting import offset.

Anchor variants

The georeferencing dialog offers two variants. A third — reuse of an existing anchor — is detected automatically and not shown as an option.

Standard

SW corner, rounded to 1 m, at the Revit origin.

Recommended for a fresh Revit project without external constraints. GeoBridge takes the south-west corner of the data bounding box, rounds it to whole metres, and sets the Survey Point to that rounded point. The model starts close to the Internal Origin (≤ 1 m offset), and the Survey Point coordinates are integers and easy to communicate.

Reference Point

UTM source point lands at the Revit origin; PBP is moved to the target point.

Recommended when a landscape architect has supplied a DWG template whose origin is a specific real-world point (Coordination Body workflow). The real UTM coordinates of this source point are entered, and GeoBridge aligns the Survey Point so this point lands at 0/0/0 in the Revit project. All later DWG imports from that landscape architect snap into place without further adjustment.

Setting the Survey Point manually first (Pro)

Sometimes you want to anchor the project before the first file import — for example when the project should rotate around a specific point that is not necessarily the SW corner of the first import. The DOP ribbon provides a dedicated "Set SP" button for this.

The Set-SP dialog does not ask for the UTM convention — without a source file, there are no source coordinates to interpret. You just type UTM coordinates in your preferred convention (e.g. 663250 / 5651500 without prefix or 32663250 / 5651500 with prefix) plus the Revit target point (typically 0/0/0). GeoBridge aligns the Survey Point so your UTM source point lands at the Revit target point.

The convention is then set at the first subsequent file import (the prefix dialog fires as usual) — or you declare it explicitly via the Event Manager → "Set convention…" (see Advanced topics).

If the project already has a Survey Point (e.g. from an imported DWG, an IFC link, or hand-set), two cases:

• Survey Point from a previous GeoBridge import — info dialog noting the documented state; setting SP is unnecessary (and not overridable in this slice).
• Survey Point without a GeoBridge record (externally anchored) — SetSp runs the adopt path: a PrefixDialog asks once for the UTM convention of this existing anchor (with-/without-prefix is pre-detected from the SP-X magnitude) and writes a synthetic GeoBridge record documenting the convention. The Survey Point is not moved. Subsequent file imports then inherit the convention silently.

Existing coordinate frame (automatic)

Detected automatically as soon as either the Survey Point is already set, or a previous GeoBridge import has left a record in the project. Instead of the full anchor dialog, a compact confirmation dialog shows the key facts of the frame:

• Survey Point: east/north position in metres
• Anchor: either "GeoBridge import: filename (anchoring mode)" — when a previous GeoBridge run set the SP — or "External anchor (DWG/IFC/masterfile/manual)" — when the SP was already in the project (see the adopt path above). For external anchors there is an additional note that drift monitoring starts with this import.
• Convention: UTM zone + with/without prefix. Suffixed with "(from previous import)" when persisted, or "(inferred from SP position)" when derived from the SP-X magnitude.

Three buttons:

• Reuse and import — Survey Point stays unchanged, the import runs with the displayed convention. Default action, Enter is enough.
• Adjust convention… — opens the prefix picker pre-filled with the displayed convention. Useful when the heuristic is off for an externally set SP (Gauß-Krüger SP, mixed-CRS project, hand-typed values). After adjusting, the import runs without further questions.
• Cancel — discard the import.

In the summary the anchor appears as "Existing coordinate frame adopted". Toggling the UTM convention later on the same project is handled via the Event Manager (see Advanced topics → Toggle UTM prefix); true re-anchoring of the Survey Point in an already-georeferenced project is not implemented today.

UTM convention — the 32-million effect

In Germany, ETRS89/UTM is the standard system. UTM zone 32 covers most of the country, zone 33 the east. The official east coordinate of a point in zone 32 is e.g. 456789.123 m. Some surveying tools (especially older CAD workflows) however prepend the zone to the number: 32456789.123 m.

Both notations are in circulation. A file with the prefix appears to GeoBridge as if the point were 32 million metres east. If the prefix is not handled, the model lands as a "32-million-metre offset from the project origin" — a classic stumbling block.

GeoBridge therefore asks explicitly which UTM convention this Revit project uses:

CRS: EPSG:25832 (ETRS89 UTM Zone 32N) First X coordinate of the file: 32456789.123 m

Which UTM convention does this Revit project use? [ Without prefix (standard UTM) ] [ With zone prefix 32 ]

"Without prefix" matches the common geoportal UTM convention. "With zone prefix" is appropriate when a landscape architect's DWG with a leading zone number has to be placed via "Auto — by shared coordinates" and the coordinates must match.

The answer is stored in the project; later imports adopt it automatically. In the Free edition, "Without prefix" is fixed — DWG-coexistence workflows require Pro.

Custom CRS for the project? (Pro)

If the source file uses a different CRS than the project — typically a GeoJSON in WGS84 (lon/lat) for a project in UTM-32 — the Pro edition reprojects automatically. The source CRS is read from the file or queried on ambiguity; GeoBridge transforms the coordinates into the project CRS before the anchoring step runs.

Free refuses imports with a mismatching CRS and points to QGIS or ogr2ogr for manual pre-reprojection.

Rotating Project North before the first import

If you use "Manage → Rotate Project North" on a pristine project and then import, GeoBridge detects the rotation and asks before the import — the Survey Point still sits at the internal origin and the rotation would have no reference point otherwise. The Pre-rotation dialog offers three paths: anchor SP from the source file, cancel and set SP manually first, or just cancel.

Details under Advanced topics → Pristine rotation.