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CAD coordinate systems: fix a drawing in the wrong place
Converted the drawing but it is shifted or somewhere else entirely? It is almost always the wrong coordinate system. Here is how to tell and how to fix it.
Why does the drawing land in the wrong place?
A DWG or DXF only stores X, Y numbers. To place them on Google Earth or in QGIS the software must know which coordinate system they belong to. This tool does not read a CRS from the drawing: it uses exactly the one you choose before converting.
With the right system the drawing matches real parcels and roads. With the wrong one the shape still looks fine but is shifted, sometimes by hundreds of metres, sometimes much further.
Read the numbers to guess the system
Open the drawing, pick any point and read its coordinates. Compare with the table.
| What the numbers look like | Usually | Choose in the tool |
|---|---|---|
| One value around 2,300,000 and another around 580,000 (millions and hundreds of thousands) | Projected metres, often VN2000 | VN2000 by province, or enter the central meridian |
| Two numbers like 105.83 and 21.02 | Longitude and latitude | WGS84 |
| Small numbers near 0 or a few thousand that match nowhere | A project's local coordinates | Cannot be placed yet: move the drawing to real coordinates in CAD first |
| Projected numbers and the drawing notes UTM or an EPSG code | A system with an EPSG code | Custom EPSG, for example 3405 (VN-2000 UTM zone 48) |
Two common traps. First, Vietnamese survey tables usually list X as northing and Y as easting, the opposite of CAD and GIS; the tool reads the drawing's X axis as east and Y axis as north. Second, with VN2000 the tool treats drawing coordinates as metres and does not convert units: a drawing in mm or cm needs to be scaled to metres in CAD first.
Choosing the system in the tool
| Option | Use when | You provide |
|---|---|---|
| VN2000 – by province | A VN2000 drawing and you know the project's province | Pick the province from the list |
| VN2000 – meridian | A VN2000 drawing where you are unsure of the province, or the file states the central meridian | The central meridian in decimal degrees, for example 105.75 |
| WGS84 | The coordinates are already longitude and latitude | Nothing more |
| EPSG | Another system with an EPSG code, for example VN-2000 UTM (6°) | The EPSG code, for example 3405 or 3406 |
The details of choosing a VN2000 province and central meridian are in their own guide.
Symptoms and fixes
| Symptom | Likely cause | Fix |
|---|---|---|
| Right shape but off by a few hundred metres to a few km | Wrong central meridian or province (a neighbouring meridian) | Check the meridian in the title block or report; choose by central meridian |
| An error and no file | Everything falls outside the valid area of the chosen system | Change the system; check whether the drawing uses local coordinates |
| Part of the drawing is missing | Objects at local coordinates or near (0,0) count as outside the area and are skipped | Delete them or move them to real coordinates in CAD, then convert again |
| The drawing is far from the project site | Wrong system (for example UTM instead of VN2000) or swapped X and Y | Try another system, or swap X and Y in CAD |
| No text in Google Earth | KML and KMZ do not export text | Choose Shapefile: text becomes points with a text field |
| Areas are not filled | A closed polyline is exported as an outline; only hatches and solids are filled | Use a hatch in CAD, or choose Shapefile (closed polylines become polygons) |
Checklist before you convert
- Read one point's coordinates and decide: metres or degrees?
- If metres: know the system (VN2000, UTM) and the central meridian or EPSG code.
- The drawing is in metres, not mm or cm.
- No stray objects at the origin (0,0) or at local coordinates.
- Pick the right output: KML or KMZ to view, SHP for GIS analysis.
- Open the result in Google Earth or QGIS and compare it with familiar roads and parcels.
Try it
Pick an output and convert your drawing.
Opens straight in Google Earth, Google My Maps and map apps.
DWG → KMZA zipped KML in a single compact file, easy to send by email or Zalo.
DWG → SHPA Shapefile ZIP (points, lines, polygons) for QGIS, ArcGIS and other GIS software.
DWG → DXFTurn DWG into an open DXF that many CAD and GIS programs can read.