How to determine map extent question?

[Ryan Ollerenshaw]

Paul Maine(ATS) wrote:
> I am writing a mapserver application that will geocode a street  
> address. I desire to plot a point in the center of the map( that is  
> the street address ) and then draw a concentric circle about the point  
> with a radius of 3 miles. How can I determine the extents of the map  
> so that I can request the appropriate size map? I desire the map  
> itself to be able to show local street names in a city.
>
>   
You can determine the extent of a shape file using:

ogrinfo -al -so file_name.shp

but i am not sure if that is what you are asking