Data - Global Bathymetry on the Cheap
Global Bathymetry
I am a long time user of Marplot. Not because it is the best GIS Freeware out there, but it is what I have always used. It has some serious limitations. And I find myself always pushing those limitations as far as I can.
The world uses JPEG images to pass information back and forth. Marplot requires that any image used within their software be in BMP format. A 3MB BMP image shrinks down to 180KB in JPEG. So, I accomodate the software and place large images into Marplot. This morning I imported my all-time largest BMP file. It is 166MB in size, a real whopper! And it loaded without any problem. In fact, it loaded and georectified without any intervention on my part.
What is it that I loaded, you ask? It is free raster data from USGS CMG InfoBank Atlas, specifically the Global Background Map. The file is 126MBs, large, too large for you dial-up folks.
The file downloaded quickly. I converted the TIFF format into BMP, opened my World Islands map in Marplot and imported the very large BMP file into my map. And, voila! It dropped in without any problems. I now have a slick new layer that shows physical features both on and off shore.
And my favorite part of this entire exercise - the data is FREE!
Life is swell! Enjoy!
Mr. Minton:
I enjoy reading about your work, especially the high res shorelines of islands I have never heard of. Although I have never used Marplot myself, it sounds like it has some serious limitations. Have you given thought to other OSS GIS packages such as uDig, QGIS, Thuban, or GRASS ? There are native windows versions for all of these packages now, and they may give you some extra features or performance in your work.
Keep up the good work,
Dylan
Posted by
Dylan Beaudette |
9/20/2006 09:46:00 AM