# Measuring land on a hill side

**URL:** <https://boards.straightdope.com/t/measuring-land-on-a-hill-side/696215>\
**Category:** Factual Questions\
**Created:** [August 22, 2014, 4:58pm UTC](https://boards.straightdope.com/t/measuring-land-on-a-hill-side/696215 "2014-08-22T16:58:19Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![The\_Great\_Unwashed](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_great_unwashed/32/4791_2.png) [@The\_Great\_Unwashed](https://boards.straightdope.com/u/The_Great_Unwashed)\
**Post date:** [August 23, 2014, 11:09pm UTC](https://boards.straightdope.com/t/measuring-land-on-a-hill-side/696215/21 "2014-08-23T23:09:27Z")

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> [@GusNSpot](#):
>
> My bad, A mapping company is not a survey company ( although many times they have both in house. Most government & civil mapping is done with aerial mapping which includes the use of photogrammetry.
> 
> Many many civil engineering firm that do subdivision plans use it a lot for calculating run off and dirt moving needs.
> 
> It is so accurate that it is used in coal pile calculation inventories. Was used to keep track of the progress in the making of the TenTom waterway and used to make the payments to the contractors which was determined by how much dirt they had moved.
> 
> It is very accurate indeed.
> 
> 27 years in the business.

Volume is a very different matter to surface area, it may seem counter-intuitive that the volume of a coal pile could be estimated within a given tolerance, but its surface area is simply not well-defined.

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**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\
**Post date:** [August 23, 2014, 11:12pm UTC](https://boards.straightdope.com/t/measuring-land-on-a-hill-side/696215/22 "2014-08-23T23:12:27Z")

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I thought It was in this thread but must have been on a different message board. Sorry… :smack:

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**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\
**Post date:** [August 24, 2014, 5:47pm UTC](https://boards.straightdope.com/t/measuring-land-on-a-hill-side/696215/23 "2014-08-24T17:47:38Z")

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> [@chappachula](#):
>
> There is only one answer : for all legal documents. the land is measured as if it were flat.
> 
> If you own a plot of land on a steep hill, you will actually have possession of more square feet than is shown on the map, on the surveyor’s plat,on the property tax assessment, and on all official documents regarding that plot of land.

On my farmland, the USDA (US Department of Agriculture) paperwork lists the acreage and then a separate figure for the farmable acres, which is almost always different. They subtract out all the land used in roads, driveways, buildings, farmyards, even the fences around the fields. This farmable acres figure is calculated to the nearest hundredth of an acre, and is very important to the farmer. For example, crop insurance charges are calculated from it, as is the field yield.

At our farm, in the mainly flat area of western Minnesota, this figure is always smaller than the actual legal size of the farm parcel of land. But I suppose that in very hilly country, there could actually be more ‘farmable acres’ than the actual legal acreage of the land!

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