Missing data points

I am missing some map data along the base map's shoreline.  The base map's shoreline is off by several hundred feed.  I'm trying to post a picture of the issue but I can't post the image from the computer.  I'll try in the reply screen.

Got it, here's the picture I see with the missing data.

If you start towards the top right on the grid (fifth line from the right and four lines down) and follow it along, you can see this missing data.  The base map's shore line is the blue line, as you can see it is way off) the real shoreline is toward the top of the picture.  It almost looks like someone used a paint program and erased about 100 feet of information between the incorrect shoreline and the real shoreline.

Any ideas?

I can't see the pictures right now, I'll try to take a look when I get home.

If you want the issue fixed, you will need to create your own custom shoreline for that area.

The reason it is doing what it is, is because shoreline data is defined as having 'water to the left' or 'water to the right' of the shoreline line.  That is why you see a section of water missing on one side of the shoreline, but on the other side is has water going right to the shore.  So, in this case, the shoreline is defined as having water to that side of the shoreline.  That is also why you see really tight contour lines next to the shore on that side, because it assumes the shoreline is 0.0ft depth.  So your closest depth finder data point is a certain depth, and the shoreline is 0.0ft, so it figures there is a really steep drop off next to shore.  

All of their basemap shoreline data was pulled from GIS data for waterbodies.  As you've seen, those are not always accurate to the actual shoreline.

Since you're going to need to create a custom shoreline in order to fix this, you may find my tutorial on creating custom shoreline data useful.