How often are coastlines updated in GIS on the Big Island of Hawaii or other areas with significant volcanic activity?

Answer 1

I believe the National Oceanic and Atmospheric Administration (NOAA) would have the most accurate, up-to-date, and reliable data available.

It looks like they've created a separate website from their main one called NOAA Shoreline Website (https://shoreline.noaa.gov/index.html) that focuses on shoreline/coastal data specifically. From that main Shoreline site, if you click on "Data Access" at the top of the page, it brings you to a bunch of spatial data resources for you. I was doing some digging and it looks like NOAA updates their coastline data as often as they can. I couldn't find an exact frequency, but maybe these resources could help!

From the "Data Access" page, if you scroll down to the bottom and click the "NOAA Continually Updated Shoreline Product (CUSP)", this provides a bit more insight into NOAA's methods for creating this data.

But what REALLY might help you is using their web map they've created! So, from that "CUSP" page, there is a blue box called on the left-hand side that has a link called "CUSP". Click on that link to view their web map with the CUSP data loaded in.

Here is the link to the web map just in case: https://www.ngs.noaa.gov/CUSP/

Once inside the web map, you can zoom to the area your interested in (i.e. Hawaii), and with the identify tool selected, click on any red coast line and attribute information will pop up with the source date inside.