Property terrain report for any Oregon taxlot

Who uses this

• Buyers of rural acreage. Compare the terrain on every parcel on the shortlist before paying for inspections on one.
• Architects and designers. Get the ground shape, slope classes and aspect at the start of a project.
• Real estate agents and sellers. Answer the slope and drainage questions buyers ask.

When to use it

• You want something to send to a client, a builder or a family member rather than a screen.
• You are shortlisting rural acreage and want the same terrain summary for each parcel.
• You need a record of what the ground looked like when the lidar was flown.

Tools for your job

Property Report is one step in a bigger question. These are the jobs it helps with, and the tools that go with it.

How to use it

1. Open Property Report and click inside the parcel, or search its address first.
2. Wait for the preview. Larger parcels take longer because more terrain is loaded.
3. Choose Download report for the PDF, or the data bundle, a ZIP with the elevation model as a GeoTIFF, the contours as GeoJSON, DXF, Shapefile and KML, a 3D terrain model as STL, the property boundary as GeoJSON and KML, and a README.

Step by step: a Hillsboro taxlot

We build the full terrain report for the same Hillsboro taxlot.

1.Open Property Report and click inside the parcel, or search its address. The panel confirms the taxlot and its area before anything is built.

2.Build report (PDF) draws the maps in your browser and has this site’s server assemble the PDF. The cover shows the parcel and four key figures: area, elevation range, mean slope and winter sun.

3.The slope page gives the mean slope and the share of the parcel in each slope class.

4.The winter sun page maps hours of direct sun on December 21 across the parcel, with the times of first and last sun.

What it showed

• Page 2 sums the report up in a few findings. The other pages cover contours, aspect, drainage, hillshade and elevation statistics, and the report closes with the county, state and federal records it does not replace, and where to check each one.
• The data bundle (ZIP) gives you the underlying files for GIS and CAD: the elevation model as a GeoTIFF, the contours as GeoJSON, DXF, Shapefile and KML, a 3D terrain model as STL, the property boundary as GeoJSON and KML, and a README.

How it works

The taxlot boundary is fetched from the county service and the USGS 3DEP elevation model is loaded for its extent. Contours, slope, aspect and elevation statistics are computed on that terrain and clipped to the boundary.

The maps are drawn in your browser and sent to this site’s server, which assembles the pages into a PDF, with the data sources named on the attribution page.

The closing checklist lists the records a terrain report cannot stand in for: county assessor and tax records, county planning and zoning, FEMA flood maps, DOGAMI hazard maps, the Oregon wildfire hazard map, wells and water rights, septic records, wetlands and a preliminary title report, each linked to the agency that holds it.

Reading the results

Slope classes are given as a share of the parcel. The report uses four bands: under 10, 10 to 20, 20 to 25 and over 25 degrees. As a rough guide, ground under 10 degrees is easy to build on, and over 25 degrees calls for a geotechnical engineer.

Aspect is where each face points. In Oregon, south-facing ground gets the most winter sun.

Elevations are in feet above NAVD 88, the national vertical datum, which is close to mean sea level.

Limits and caveats

• A terrain report is not a survey, a geotechnical report or a planning review. It shows the ground shape on the date the lidar was flown.
• Where lidar has not been flown, the USGS 3DEP model falls back to its 1/3 arc-second layer, about 33 ft per pixel, and downloads state what share of the area came from it. That coarser model is not fit for site-scale decisions. DOGAMI reports about 99% of Oregon covered by at least one lidar project. The fallback is rare.
• Parcels larger than the area limit are refused. Draw a smaller area with the other tools instead.

Data and attribution

Results come from the USGS 3D Elevation Program (3DEP) bare-earth elevation model: lidar at 3.3 ft per pixel where it has been flown, and the 1/3 arc-second model, about 33 ft per pixel, elsewhere, with elevations above NAVD 88. The tools with a surface option (Sunlight, Viewshed, Sightline, Object Heights) read DOGAMI’s statewide digital surface model of trees and buildings.

USGS 3DEP elevation data and USGS maps are U.S. Government works in the public domain: you may use the results, including commercially. A credit to the USGS 3D Elevation Program is appreciated, and every file you download carries it. DOGAMI lidar products are published by the State of Oregon; credit "DOGAMI / Oregon Lidar Consortium". County taxlot boundaries are the assessor's GIS data, not surveys, and each county publishes its own disclaimer, shown with the parcel. The aerial basemap is from Esri and follows Esri's terms; it is not included in downloads.

Questions

Related

Related tools

• Property — Selects the county assessor’s taxlot under your click and uses its boundary as the analysis area for every other tool.
• Saved Properties — Keeps up to 5 places in your browser and compares their elevation, slope, winter sunlight and drainage side by side.
• Slope & Aspect — Maps how steep every part of your area is and which compass direction each face points, with a full breakdown of slope classes and aspect shares.
• Sunlight — Models hours of direct sun across a site on any day of the year, with shadows from terrain up to 1.86 mi away and, where DOGAMI’s surface model exists, from trees and buildings.

Guides

• Terrain Checks Before Buying Rural Land in Oregon
• Slope Maps for a Building Permit on Sloping Land