Can You Trust GIS Viewers Over Professional Surveying?
At Jepson and Associates, many property owners approach us with questions. They often reference maps they've seen on tools like the Whatcom County Tax Parcel Viewer or Bellingham's City IQ. These impressive tools reflect the local government's push for better tech. Yet, they aren't designed to nail down exact property boundaries.
These mapping tools have a big job. They assist the government, which relies heavily on our property taxes. By blending satellite images with addresses, GIS mapping offers a general idea of where properties are for tax and utility reasons. However, these are not precision tools for detailed boundary work.
For a clearer picture of property edges, satellite images won't always cut it. Deeds and Plats are essential. These documents detail your property's specifics. For instance, a house might appear on the actual boundary line in the satellite view. Only a detailed survey can confirm the exact position.
County Assesor’’s satellite image compared to plat survey drawing.
Take the satellite image of house 3821 as an example. The parcel lines around it suggest potential mismatches with the actual imagery. The house seems to extend beyond the east boundary, and a nearby fence might not align with the west line. Note the oddity in the Northeast corner: while the plat indicates one corner, the parcel lines hint at two. Without a professional survey, it's hard to confirm. However, the mismatch might be as much as 5-10 feet, possibly due to adjustments for neighboring plats.
Crafting a full county map, integrating all Plats and Deeds, is quite the endeavor. And while satellite technology is powerful, it isn't foolproof. So, when we merge these elements, the outcome is more an informed estimate than pinpoint accuracy.
At times, GIS tools can be surprisingly spot-on. We do use them as a starting point to understand property corners. Yet, discrepancies between tool data and real-world markers are common and highlight why professional land surveying is so essential. A surveyor delves into records and then measures onsite with top-notch equipment. The end result is a reliable map that provides a clear snapshot of your property.
The Whatcom County Tax Parcel Viewer and the Sacramento County assessor's maps include warnings. They stress that these tools are for information and not for legal use.
"This Tax Parcel Viewer application is intended for public use to access tax parcels and related assessment information. Information obtained from this web map application cannot be used for legal purposes or official documents. Consult Property deeds for full legal descriptions of property Boundaries". - Whatcom County
"Assessor parcel maps are prepared for assessment purposes only and by law show information AS RECORDED rather than as obtained, for instance, from an independent onsite survey. Being based on recorded documents, the assessor parcel maps may not match exactly what is seen or measured in person and overlays on aerial photographs may not reflect actual parcel boundaries. Assessor Maps are NOT surveys and as such should not be used in either defining property lines or in resolving disputes between neighbors… Your property boundaries are defined by the legal description on your deed. The language on the deed typically references distances and bearings. It may also reference a specific lot or parcel of a subdivision or parcel map which has the legal boundaries delineated on the recorded map. To identify the physical boundaries of your property, you will need to contact a licensed land surveyor or civil engineer." - Sacramento County
In short, GIS viewers have their limits. You need a professional survey if you want clear, certain property boundaries. It's the best way to be sure.
- Jepson Team Member