|tim (tim paige)
Joined: 25 Feb 2009
Location: San Diego
|Posted: Thu Apr 07, 2011 12:05 am Post subject:
How to? - gdal_translate .asc to geoTiff and osgdem to flat terrain
My starting file of interest is an ASC file with the following gdalinfo
Driver: AAIGrid/Arc/Info ASCII Grid
Size is 11880, 9720
Coordinate System is `'
Origin = (-117.900000000000010,33.399999999999991)
Pixel Size = (0.000092592592593,-0.000092592592593)
Upper Left (-117.9000000, 33.4000000)
Lower Left (-117.9000000, 32.5000000)
Upper Right (-116.8000000, 33.4000000)
Lower Right (-116.8000000, 32.5000000)
Center (-117.3500000, 32.9500000)
Band 1 Block=11880x1 Type=Float32, ColorInterp=Undefined
Then I would translate to a tiff
gdal_translate sd_1_3_110805.asc lj.tif
Then I used osgdem
osgdemd --cs "+proj=latlong +datum=WGS84" -d sd_1_3_110805.asc -l 6 -v 2 -o lj.ive
I would like to translate that file to one suitable for creating a flat terrain for use with osgOcean. Doing anything less than specifying geocentric yields a nice terrain database that is 180 degrees out, so I give up on that.
My desire is to take my interesting combination of bathymetric and topographic elevation data (which I can view geocentrically correctly) and make a flat terrain which will still allow me to get lat lon and alt usage. I would like to be able to "fly" above and below my section of ocean which I hope to place in the area of interest while moving around.
In this "ocean centric" world, I have had problems finding my terrain with reference to my ocean and model.
1. what may I use for gdal_translate to get in shape for flat terrain?
2. could I do it all with osgdem?
3. why is my conversion "backwards" unless I specify geocentric?
4. If I use a geocentric model... what would be appropriate to use in order to get my landmass in a position suitable for my fixed ocean?
5. Does a getBoundingSpere on a geocentric terrain model return the center of the earth? Or does it return the center of the peaks and valleys of the model? (either way I have been unsuccessful in moving mountains such that they are visible with my ocean)
I am using "bathymetryDEM" located at...
[url] http://seafloor.csumb.edu/SFMLwebDATA_s.htm#LJ [/url]