Calculating national coastlines

Question

I am very new to ArcGIS and have the following problem: I have a shapefile with around 1500 regions worldwide and want to calculate for each region the distance up to the coastline of its own country (or if the country has no access to the ocean, the nearest coastline).

I have a shapefile with data on all coastlines worldwide. However, the lines forming the coastlines are not country-specific (i.e. there is not 1 line feature for the coastline of each country).

Is it possible to extract national coastlines from this data? How could I proceed?

Answer 1

• create point every time country boundaries intersect ("feature vertices to point" if you have a clean geometry).

• use "split line at point" to split the coastlines with those points

• create a buffer around each country

• loop on each country to select the regions and coastlines inside it, and run "near" or "spatial join" to compute the distance. The iteration can be done using model builder iterator or arcpy.

remark : instead of split point, you can intersect the buffers and the coastlines, but this will create small artefacts.