# [uf-discuss] Geo Radius, Area of Interest

Andrew Turner ajturner at highearthorbit.com
Wed Oct 4 07:01:29 PDT 2006

```There have been some great ideas and thoughts that poured through the
list yesterday. Here's an attempt to summarize and re-gather thoughts
and needs. I think there are couple of use cases people have thrown
out there, each with their own problems and possible solutions
(completely up for discussion). I just want to have us arguing about
the appropriate topics and not bashing head on what the actual problem
is. :)

---
1) Precision
Summary: ability to mark the approximate area these lat/lon
coordinates apply to due to not sure of exactly where something was,
or imprecise measuring device

Example: have lat/lon of the center of a park, and took pictures at
various places in the park.

Problems: users probably don't know that 0.0001 degree = 11.1 meters
at the Equator - but also varies depending on the latitude. Also,
dropping digits off the end doesn't specify if 41.345 is "inaccurate",
or really accurate 41.3450000 (b/c zeros would be dropped when stored
in code as a number, though not as a string)

Solution? specify a precision that is +/- a distance. e.g. "give or
take <span class="precision">10 meters</span>

2) Radius
Summary: rough area that the coordinates apply to

Example: expected landing area for a parachutist/rover

Solution? allow <span class="radius">42 meters</span>

3) Feature area
Summary: coordinates are the center of a larger area of a certain type
of unknown size

Example: Took a picture of a mountain or a city. Want to just say, the
mountain is at Lat x Lon and is a mountain in size/area

Solution?: featuretypetag="mountain" as used by GeoRSS

4) Polygon/line
Summary: lay out a track/line, or define a specific boundary of a location

Example: A hike or a plot of land definition, such as for Real Estate

Solution? Use an ordered list for a line <ol class="track"><li class="geo"> ....
and the same for a polygon: <ol class="polygon"><li class="geo"> ...
Also look at the directions uf discussions.

---

Andrew Turner
```

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