Contour Map of Your Property
Click an Oregon property and see contour lines over its county taxlot, generated from the USGS 3DEP lidar elevation model, at any interval from 1 ft.
Start with your property
Search an address, click the parcel, pick an interval. Nothing to install and no account.
Open the Property tool →Why the property boundary matters
Most online terrain tools ask you to drag a rectangle. That is fine for a watershed and wrong for a property, because a property is not a rectangle. Draw a box around a lot and you get contours for the neighbor's slope, the road and half the field behind — then you spend an afternoon in CAD trimming to the line you care about.
Selecting the parcel instead uses the county assessor's GIS taxlot as the analysis area, in the counties that publish an open taxlot service (Metro RLIS for Multnomah, Washington and Clackamas, Lane Council of Governments for Lane, and the other county services the site lists). The contours you see on the map stop at the taxlot line, and so do the GeoJSON and KML files saved from the Contour Lines panel; terrain statistics describe your land and nobody else's. Taxlots are assessment maps, not surveys; where no county service is available, the tool says so.
What a property contour map tells you
- Where is the flat ground? Widely spaced contours mean gentle ground: the building pad, the shop site, the part of the field you can work.
- How much fall is there, and which way? The difference between the highest and lowest contour is the fall across the lot. Its direction decides where water goes, whether a gravity sewer or septic line works, and how much grading a level pad needs.
- Where does water collect? Contours that bend uphill trace a swale or gully; a closed loop at a low point is a hollow that will pond in a wet Oregon winter.
- Where are the steep parts? Contours crowding together mark banks, cut slopes and old slides — on acreage, often the difference between usable land and scenery.
- Is the ground graded or natural? Unnaturally straight, evenly spaced contours usually mean earthwork: an old pad, a logging road, a filled draw. Worth knowing before you dig.
Choosing a contour interval
The interval is the vertical distance between contour lines, and picking it badly is the most common way to end up with an unreadable plan. The right interval depends on the size of the site and how much relief it has.
| Site | Interval | Why |
|---|---|---|
| City or suburban lot | 1 ft | Shows the fall across a lot that may only drop a few feet in total |
| A few acres | 2 ft | Enough detail for a house site and drainage without crowding |
| Farm, ranch or timber ground | 5–10 ft | Reads as landform — ridges, draws, faces — rather than noise |
| Steep ground | 20–40 ft | On a Coast Range or Columbia Gorge slope, fine contours merge into a solid band |
Contours render on the map as soon as you pick an interval, so the practical approach is to try one, look, and step up or down.
Exporting for the people who need it
A contour map is usually made for someone else — a designer, an engineer, a contractor, the county. Each wants a different file.
- DXF for AutoCAD, Civil 3D, Revit and ArchiCAD, in Oregon Statewide Lambert, feet (EPSG:2992): contours arrive as polylines with their elevation, ready to build a surface.
- GeoJSON for QGIS and ArcGIS, in WGS84, with each line's elevation in feet.
- PDF for printing, marking up by hand or attaching to an application, labeled in feet.
- STL and OBJ for a printed or rendered 3D model of the site.
- Aerial photo of the lot from USGS NAIP (public domain), a JPEG with a world file that drops in under the contours in CAD or GIS, covering the taxlot plus 100 ft on every side; choose Aerial in the Download Data tool.
The Contour Lines panel saves GeoJSON and KML clipped to the taxlot. Every format above comes from the Download Data tool, whose files cover the rectangle around the property, not the taxlot outline, so the drawing shows the lot in its setting and your designer trims to the boundary where the plan needs it.
More than contours, from the same click
Once a property is selected, the other terrain tools work on the same boundary.
Where the accuracy sits, honestly
Ground elevations on this site come from the USGS 3D Elevation Program (3DEP) seamless bare-earth model: 3.3 ft per pixel where lidar has been flown and about 33 ft per pixel elsewhere, with elevations above NAVD 88. The data is in the public domain. Most of Oregon’s lidar was flown through the Oregon Lidar Consortium, run by DOGAMI, the Oregon Department of Geology and Mineral Industries. DOGAMI reports about 99% of Oregon covered by at least one lidar project. More from the USGS 3D Elevation Program and DOGAMI’s lidar program.
Vertical accuracy is inherited from the lidar project that covers your area — individual Oregon Lidar Consortium projects report vendor RMSE of a few inches or less in DOGAMI’s project records — and is not asserted by this tool. Three things are worth being clear about:
- Age. The model shows the ground as it was when it was flown. Check the project for your address on the lidar coverage page before trusting contours over recent work.
- Coverage. Where there is no lidar work unit, the model falls back to about 33 ft per pixel, and fine intervals mean little. Every Download Data file states what share of its area came from the fallback.
- Standing. This is a measurement, not a survey. For a boundary question, a finished floor elevation or anything a building permit depends on, hire a licensed land surveyor and check with your county planning department.
Related guides
- Slope maps for building — how steep a lot is, and which way it faces.
- Terrain checks before buying rural land — slope, aspect and drainage before you make an offer.
- Lidar coverage in Oregon — which project flew your area, and when.
- Contour lines for Oregon — the general guide to generating and exporting contours.
- Topographic maps of Oregon — reading contours, and how custom maps differ from USGS quads.
Frequently asked questions
Can I get a contour map of my property for free?
You can make and view one for free. Click your property on the map and contours are generated from the USGS 3DEP elevation model over the county taxlot, with no account and nothing to install. Downloading the files needs a pass: US$29 for 24 hours, US$99 for 30 days or US$399 for 12 months.
What contour interval should I choose for a house lot?
For a typical city or suburban lot, 1 ft is usually right: it shows the fall across the lot without becoming a thicket of lines. For a few acres, 2 ft reads more clearly; for a farm or ranch, 5 to 10 ft. If the lines are so dense you cannot see the ground between them, step the interval up.
Is this the same as a surveyed topographic map?
No, and the difference matters. A lidar contour map is an aerial measurement of the ground, as it was on the day the lidar was flown. A topographic survey is measured on the ground by a licensed land surveyor, to a tighter tolerance, on a known date, and carries professional responsibility. Use lidar contours for site assessment, feasibility, early design and understanding what you are buying. Use a surveyor when a boundary, a legal elevation or a permit condition depends on the number.
Will the county accept these contours with a building permit application?
It depends on what the contours are for, and only your county planning department can answer for your application. Lidar contours are widely used for site analysis and early planning; where the county needs surveyed elevations, it will say so. Ask before you rely on them.
How current is the elevation data?
It depends on when your area was flown. Contours cannot show grading, a new driveway or a subdivision built after the flight. Check the lidar project for your address on the lidar coverage page before relying on contours over recent work.
What format should I export for my architect or engineer?
DXF for AutoCAD, Civil 3D, Revit or ArchiCAD: contours arrive as polylines with their elevation, in Oregon Statewide Lambert, feet (EPSG:2992). GeoJSON for QGIS or ArcGIS. PDF for something to print, mark up or attach to an application. These come from Download Data and cover the rectangle around the property rather than the taxlot outline; the Contour Lines panel also saves GeoJSON and KML clipped to the taxlot.
Does the contour map include buildings and trees?
No. The contours come from the bare-earth elevation model, with trees and structures removed. That is what you want for ground contours. For tree and roof heights, the Object Heights tool reads DOGAMI’s surface model.