[postgis-users] generating ocean

[Guido Lemoine]

For a good quality global coastline (shoreline) check out the gshhs 
(full res version)
at http://www.soest.hawaii.edu/wessel/gshhs/gshhs.html

We have loaded this into postgis and use it for land masking of SAR 
imagery, so
that we can detect vessel positions (ocean masking is the reverse). The 
global consistency
and detail of gshhs is remarkable (better than VMAP0). For ocean 
masking, we use the
approach just sent by Brent Wood (i.e. differencing with a bounding box 
that is, in our
case, the SAR image frame).

Guido Lemoine



Brent Wood wrote:

>--- Christo Du Preez <christo at mecola.com> wrote:
>
>  
>
>>Hi All,
>>
>>What is the best way to generate an ocean geometry if I have a country 
>>boundary?  Or is this downloadable somewhere as free gis?
>>    
>>
>
>
>There are a few free global datasets, but you will probably find the coastlines
>vary from yours.
>
>You might try to select the difference between your coastline & a bounding box
>encompassing the coastline area, the postgis difference funtion should do this.
>
>
>Brent Wood
>
>_______________________________________________
>postgis-users mailing list
>postgis-users at postgis.refractions.net
>http://postgis.refractions.net/mailman/listinfo/postgis-users
>
>  
>