Hi Scott,
I have worked with MapInfo and Vertical Mapper for 7 years. I would suggest making a copy of your multibeam dataset and using the grid calculator and multiplying the elevation data by zero. This will give a secondary elevation dataset which you can drap the 'tif' image onto with the same spatial extent of the multibeam but be at a depth of zero metres below sea level.
Stan Johnston GIS tech. OCMD, DFO BIO, Dart. NS.
PS - look me up in the government email list and I can walk you through it. Lesley Carter knows me!
----- Original Message ----- From: "Lewis,Scott [Dartmouth]" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, April 01, 2005 15:28
Subject: MI-L Re: Grid overlays using Vertical Mapper
Hello,
Perhaps someone might be able to suggest a solution to my problem; or point me in the right direction:
I have some multibeam data (seafloor bathymetry) in grid format that I want to overlay with some raster navigational charts using Vertical Mapper. I am relatively new to Vertical mapper, but so far I have turned the charts (.tif files) into 'drape' files and have added them onto the multibeam grid (in the 3d viewer). My problem is that I don't know how to 'zero' the chart to equal mean sea level. When I overlay the chart with the multibeam, the multibeam appears to hover well above the chart itself. What I would like to do is be able to see is the chart lying flat @ mean sea level, and the seafloor depths appearing below the chart surface. The depths are currently in negative numbers and I would like to assign 'zero' values to the raster chart. I believe the number of cells differs b/w the chart and the multibeam grid.
I do not use MapBasic, so any 'simpler' solutions would be much appreciated.
Thanks,
Scott
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