global distances (great circle distances)

[Anonymous User]

Dear everyone,

I have a problem that seems difficult for me to solve. For a large number of coordinates (points) I have to calculate the great circle distance to the nearest continent. The points are distributed accross the globe.

Does anyone here have an idea about if this can be conducted in ArcGIS or alternatively suggest another application?

best wishes,
Peder Bøcher
Aarhus University, Denmark

[DaleHoneycutt]

Peder:
I assume that you have a polygon dataset of continent boundaries that you can use.  If so, you can use the Near tool or the Generate Near Table tool to find the closest continent (polygon) to your point.  Be sure to check on the Location parameter which will output the x,y of the nearest point on the continent polygon (NEAR_X and NEAR_Y fields)

Near and Generate Near Table use Euclidean distance to determine the closest (near) feature.  But what you can do as a post process is to create a line that starts at the location of your input point and ends at the NEAR_X and NEAR_Y point.  You can then calculate the geodesic distance of this line.  See the blog post  Calculating Geodesic Distance Between Points for methodology to do this.

At 10.2.1, we've rewritten the Near and Generate Near Table tools use geodesic distance calculations.