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

Charles Iliya Krempeaux supercanadian at gmail.com
Wed Oct 4 09:38:27 PDT 2006

```Hello Andrew,

I haven't yet gone over the previous thread yet.  (Too busy with work.)

But you may want to allow the concept of time in there.

And say things like... this picture was taken at the coordinates at
this date time.

A reason for this is that the coordinates for a location can change
over time.  Due to an Earth quake violently shifting the land over
time.  Continental drift.  Or something else.

See ya

On 10/4/06, Andrew Turner <ajturner at highearthorbit.com> wrote:
> 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>
>
> 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
>

--
Charles Iliya Krempeaux, B.Sc.

charles @ reptile.ca