How to Convert DWG to KML for Google Earth: Complete Step-by-Step Guide

Converting DWG to KML is routine work in civil engineering, surveying, utility coordination, and GIS production. The actual export is easy. The coordinate system is where projects go sideways.

Most failed conversions happen because the DWG was never properly georeferenced before export. The result is familiar:

• The drawing lands in the Atlantic Ocean
• The site appears miles from its actual location
• Parcel lines do not match imagery
• Utility alignments shift several feet
• The model imports rotated or scaled incorrectly

If you need to open an AutoCAD DWG in Google Earth, this guide covers the workflows that hold up in real projects:

• AutoCAD Map 3D
• Civil 3D
• QGIS
• DWG → DXF → KML workflows
• KML vs KMZ
• Coordinate system troubleshooting
• Survey-grade alignment checks

What Is a DWG File?

A DWG file is AutoCAD’s native format. It stores:

• Geometry
• Layers
• Blocks
• Annotation
• Surfaces
• Alignments
• Pipe networks
• Coordinate data
• Object attributes

A DWG may use:

• Local coordinates
• State Plane coordinates
• UTM coordinates
• Ground coordinates
• Arbitrary project grids

That matters because KML only supports geographic coordinates in WGS84.

What Is a KML File?

KML (Keyhole Markup Language) is the geospatial format used by:

• Google Earth
• Google Earth Pro
• Google Maps

KML uses:

• WGS84
• EPSG:4326
• Latitude / Longitude coordinates

A KML file is designed for visualization, not engineering production drafting.

DWG vs KML vs KMZ

A KMZ file is simply a zipped KML that may include:

• Images
• Icons
• Embedded overlays
• Textures

Google Earth supports both KML and KMZ.

The Golden Rule: Verify the Coordinate System First

Before exporting anything, confirm the DWG has a valid coordinate system assigned.

This is the step most users skip.

Typical failure scenarios:

KML requires:

• WGS84
• EPSG:4326

Your CAD or GIS software must perform the transformation during export.

Why “Null Island” Happens

When a DWG has no valid coordinate system, many applications default the geometry to:

Latitude: 0
Longitude: 0

That location is commonly called Null Island.

It sits off the west coast of Africa in the Gulf of Guinea.

If your drawing appears there inside Google Earth, the export itself probably worked correctly. The coordinate system did not.

That is why CRS assignment is non-negotiable.

Before You Convert: Clean the DWG

Bad drawings produce bad exports.

Before exporting:

Run cleanup commands

PURGE
AUDIT
-OVERKILL

Then verify:

• Unused layers removed
• Duplicate geometry removed
• Broken entities repaired
• XRefs resolved
• Units confirmed
• Proxy objects identified

Civil 3D Users: Use EXPORTTOAUTOCAD First

This step saves a lot of failed exports.

Civil 3D objects are not standard CAD entities. Surfaces, alignments, corridors, pipe networks, and labels often export poorly to KML.

Before exporting:

EXPORTTOAUTOCAD

Why this matters:

• Converts Civil 3D objects into standard AutoCAD geometry
• Removes dependency on object enablers
• Prevents missing labels
• Reduces proxy object issues
• Improves KML compatibility

Without this step, Google Earth exports may:

• Omit surfaces
• Ignore labels
• Corrupt alignments
• Produce incomplete geometry

For production deliverables, flatten the drawing first.

Verify Units Before Export

One of the most common alignment problems is unit mismatch.

The US Survey Foot vs International Foot Trap

This issue still breaks State Plane exports regularly.

The problem

The drawing was created in:

• US Survey Feet

but exported as:

• International Feet

The positional shift can reach several feet across large coordinate systems.

That is enough to fail survey validation.

The fix

Verify:

UNITS
DWGUNITS

Then confirm the assigned coordinate system uses the same unit definition.

This matters especially for:

• State Plane systems
• DOT projects
• Utility coordination
• Survey control work

Method 1: Convert DWG to KML Using AutoCAD Map 3D or Civil 3D

This is the most reliable workflow because Autodesk handles the coordinate transformation internally.

Standard AutoCAD may not include full geospatial export functionality depending on version and installed toolsets.

Step 1 — Assign the Coordinate System

Use:

MAPCSASSIGN

Select the correct coordinate system for the project.

Examples:

• NAD83 State Plane
• UTM Zone
• National grid systems
• Municipal coordinate systems

Do not guess the CRS.

If the file came from another consultant, verify coordinates with the surveyor or GIS manager.

Step 2 — Verify Real-World Coordinates

Use:

GEOGRAPHICLOCATION

Then verify:

• Survey control points
• Benchmarks
• Parcel corners
• Easting/Northing values

If coordinates appear extremely small, the drawing may still be local-only CAD geometry.

Step 3 — Export to KML

There are two common export workflows.

Option A — MAPEXPORT

Use:

MAPEXPORT

Then:

1. Select Google KML
2. Choose export location
3. Select layers or objects
4. Export object data if required
5. Finish export

Option B — EXPORTKML

Newer Civil 3D versions also support:

EXPORTKML

This wizard-based workflow is easier for users who are not GIS specialists.

The command handles:

• Coordinate transformation
• Layer export
• KML generation
• Basic visualization settings

For straightforward Google Earth exports, it is usually faster than MAPEXPORT.

Step 4 — Verify in Google Earth

Open the KML inside:

Google Earth Pro

Then verify against aerial imagery:

• Building footprints
• Utility alignments
• Property boundaries
• Road centerlines
• Control monuments

Never assume the export succeeded simply because the file opens.

Method 2: Convert DWG to KML Using QGIS

For teams without Autodesk Map products, QGIS is the best free workflow.

QGIS Official Site

QGIS handles reprojection very well if the source CRS is known.

Step 1 — Import the DWG

In QGIS:

Project → Import/Export → Import Layers from DWG/DXF

Some DWG files import poorly depending on version and object complexity.

If import problems appear:

1. Open DWG in AutoCAD
2. Save As DXF
3. Import DXF instead

DXF is often more stable for interoperability.

Step 2 — Assign the Source CRS

Right-click the imported layer:

Set Layer CRS

Assign the original coordinate system used by the CAD file.

This step tells QGIS what the coordinates represent.

It does not transform the geometry yet.

Step 3 — Export as KML

Right-click the layer:

Export → Save Features As

Choose:

Keyhole Markup Language [KML]

Then set:

CRS = EPSG:4326 - WGS84

QGIS handles the reprojection automatically during export.

Step 4 — Verify Alignment

Open the exported KML inside Google Earth.

Check:

• Parcel edges
• Pavement limits
• Survey monuments
• Utility crossings
• Existing GIS references

If alignment is wrong, the source CRS is usually incorrect.

Method 3: DWG → DXF → KML Workflow

This workflow is often more reliable for older or messy CAD files.

Recommended when:

• DWG import fails
• Proxy objects exist
• Third-party CAD software was used
• Legacy drawings are involved
• QGIS struggles with the DWG

Workflow

1. Open DWG in AutoCAD
2. Save As DXF
3. Import DXF into QGIS
4. Assign source CRS
5. Export to KML using EPSG:4326

This workflow resolves many interoperability problems.

Method 4: Online DWG to KML Converters

Online converters are acceptable for quick visualization.

They are not ideal for engineering-grade deliverables.

Examples:

• Aspose CAD Converter
• CloudConvert

Pros

• Fast
• No installation
• Useful for quick review

Cons

• Weak CRS handling
• Poor support for complex CAD objects
• XRefs may fail
• No survey-grade accuracy
• Data security concerns
• Limited export control

Practical rule

Only use online converters if the DWG is already georeferenced correctly.

Most raw CAD drawings are not.

Why DWG to KML Conversions Fail

Problem: File Opens in the Ocean

Cause

No coordinate system assigned.

Fix

Assign the correct CRS before export.

Problem: Drawing Is Shifted Several Feet

Cause

Usually one of these:

• Grid-to-ground scaling issue
• Wrong foot definition
• Incorrect survey scale factor

Fix

Verify:

• Combined scale factor
• Grid vs ground coordinates
• US Survey Foot vs International Foot
• Coordinate system definition

Problem: Geometry Is Rotated

Cause

Local CAD north differs from true north.

Fix

Apply proper georeferencing before export.

Problem: KML Is Empty

Cause

Proxy objects or unsupported Civil 3D entities.

Fix

Use:

EXPORTTOAUTOCAD

Then re-export.

Problem: Curves Look Jagged

Cause

KML does not support true CAD arcs.

Fix

Increase tessellation before export.

Problem: Layers Are Missing

Cause

Layer filtering or unsupported objects.

Fix

Verify:

• Layer visibility
• Export selection
• Object compatibility

Problem: File Is Too Large

Cause

Dense geometry or excessive vertices.

Fix

Simplify geometry before export.

Especially for:

• Contours
• Surface triangulation
• Utility networks
• LiDAR-derived data

Best Practices for Accurate Google Earth Alignment

Use Real Survey Coordinates

Avoid arbitrary CAD origins whenever possible.

Verify Coordinate Systems Early

Fixing CRS mistakes after design coordination starts wastes time quickly.

Confirm Units

Check:

• Feet
• US Survey Feet
• International Feet
• Meters

before export.

Verify Against Known Control

Always compare exported KML against:

• Orthophotos
• GIS basemaps
• Survey monuments
• Property corners

Keep Geometry Simple

Google Earth is not a CAD production environment.

Heavy engineering geometry can become unstable.

Recommended Workflow by Scenario

Summary Checklist

Before Export

• Run PURGE and AUDIT
• Resolve XRefs
• Verify units
• Confirm CRS
• Flatten Civil 3D objects if needed
• Remove unnecessary geometry

During Export

• Use WGS84 / EPSG:4326
• Verify layer selection
• Export object data if needed
• Check coordinate transformation settings

After Export

• Open in Google Earth
• Verify orientation
• Verify scale
• Check imagery alignment
• Confirm parcel and utility positions

FAQ

Can Google Earth open DWG files directly?

No. Google Earth requires:

• KML
• KMZ

DWG files must be converted first.

What coordinate system does KML use?

KML uses:

• WGS84
• EPSG:4326
• Latitude / Longitude coordinates

Why does my DWG appear at 0,0 in Google Earth?

The DWG likely had no assigned coordinate system before export.

That location is commonly called Null Island.

Why is my KML offset several feet?

Common causes:

• US Survey Foot vs International Foot mismatch
• Grid-to-ground scaling
• Wrong CRS
• Incorrect survey scale factor

What does EXPORTTOAUTOCAD do?

It converts Civil 3D objects into standard AutoCAD entities.

This improves compatibility with:

• KML exports
• GIS software
• Third-party CAD applications

Can QGIS convert DWG to KML?

Yes. QGIS can import DWG or DXF files and export them as KML after assigning the correct CRS.

Is KMZ better than KML?

KMZ is simply a compressed KML package.

It is more portable and handles embedded assets more efficiently.

Why are labels missing after export?

Civil 3D labels and objects may not export correctly.

Use:

EXPORTTOAUTOCAD

before exporting.

Does standard AutoCAD support KML export?

Not always.

Reliable geospatial export is typically handled through:

• AutoCAD Map 3D
• Civil 3D
• GIS toolsets

Should I use DWG or DXF with QGIS?

DXF is often more stable for interoperability, especially with older or complex drawings.

Final Field Notes

If the drawing matters legally, financially, or operationally, do not trust the first export blindly.

Always verify:

• Coordinate system
• Units
• Rotation
• Scale
• Control alignment
• Parcel fit
• Utility locations

The export itself takes minutes.

Correcting a bad coordinate transformation after construction staking begins is a much more expensive problem.