Hi Michelle,

I can help you with this. The basic steps are:

1.    Obtain ETOPO2 as a properly georeferenced grid that you can view in ArcGIS. (For now, I will skip how to do this, but if you need help, let me know.)

2.    Add a field to your point features named Depth (or whatever you like).

3.    Run the MGET tool named Interpolate Raster Values at Points using the ETOPO2 raster, the point features, and the field you just added as the first three parameters to the tool. You can also change the Interpolation Method as desired, depending on what kind of interpolation you want to be done. (All MGET parameters have documentation. If you don’t see it on the right side of the tool dialog box, click the Show Help>> button.)

You can also do this with the ArcGIS Spatial Analyst toolbox without MGET. There are three tools from Spatial Analyst that all do it, in slightly different ways: Extract Values to Points, Extract Multi Values to Points, and Sample. Extract Values to Points does not require you to add a field but creates a new feature class with a new field named by ArcGIS.

Extract Multi Values to Points is essentially identical to MGET’s tool. It did not exist in ArcGIS at the time we developed the MGET tool; now that ESRI added it, MGET’s tool is somewhat superfluous.

Sample outputs a table instead of a feature class. It has the advantage of being the only tool of all of these (including MGET) that can do cubic convolution as the interpolation technique. But it can be cumbersome to use. And for at least one release of ArcGIS, it did not work (I’m not sure why).

Best,

Jason

From: [mailto:] On Behalf Of Valliant, Michelle L
Sent: Thursday, July 14, 2016 8:38 AM
To:
Subject: [mget-help] Assistance with obtaining bathymetry depth measurements

Hello,

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