Version 2 of SRTM data available

[Guest Horst]

Hello Vlada,Thank you, Sherlock Holmes and map maker! :)Good to know, things will get fixed!Horst

[rhumbaflappy 113]

Hi all.Perhaps I should start a new thread, but here goes.The site for "finished" srtm data doesn't work for me... and hasn't for a while. I don't know if the USGS isn't aware, or if my settings are wrong for internet explorer. Can't download a thing ( miss the old interface that never failed! ).http://seamless.usgs.govMeanwhile, I'm unable to find an alternate source of finished SRTM-2.I sent the USGS a very nasty e-mail about their website interface and maintenance. As a US citizen, I don't believe I should get anything less than a fully functional website for my tax dollars. I don't expect the world... I just expect this website to work as designed.( Speaking of poor interfaces, has anyone checked out the NGA's Raster roam site... terrible! )http://geoengine.nima.mil/geospatial/SW_TO.../rast_roam.htmlDick

[Holger 0]

Hi Dick,good point about those website GUIs - they are pretty user-unfriendly indeed.I just tried downloading SRTM data and they aren't available for me either (NED works). I wonder whether this has to do with them fixing the lateral offset discussed in this thread? If so, they should have made a statement to that effect in their news section...Cheers, Holger

[Guest vlada stoje]

Hi Holger, Dick, Horst and all,I can also confirm that the seamless website doesn

[rhumbaflappy 113]

Hi all.Another product related to SRTM is the water body data:http://eros.usgs.gov/products/elevation/swbd.htmlIt costs $60 US. I think the resolution is about 30 meters. It might be usable for producing LWMs and VTP shorelines... but $60 US for the DVD is a bit steep for me.I have made masks to alter the SRTM data using landsat7 images as a background raster image. I then create POLYS for the masks, and with some creative PaintShopPro work, and using Luis Sa's DEM2BSQ program, I can alter the mesh for coastlines quite well. This helps a lot in CFS2, where LWM water has no elevation... I just flatten the mesh data itself!Dick

[Holger 0]

Hi Dick,interesting find on the water body data. When the SRTM v2 first became available I downloaded a chunk of Patagonia and was happy to see that the oceans and inlets are now well defined (i.e., 0-m flattened), which allowed me to run them as is through Slartibartfast. Slarti needs a water mask to create the lakes (which the SRTM data don't provide) but the ocean LWM/VTP files are now very easy to generate. The lake water masks can be generated by Landsat as you say (though it requires some intensive pre-processing to remove shadows in mountainous terrain) or, perhaps, by the water body DVD data (whoever is willing to fork out the $120 for both hemispheres). I wonder if the quality of those data is sufficient for the FS design team to use in the next version of FS?!? I compared a number of lake outlines and elevations in the SRTM v2 data with my topographic maps and the spatial match is pretty good though the elevations are usually off by 10-20m (of course, I don't know whether the topographic maps are correct in all cases either).Cheers, Holger

[Holger 0]

Hi Vlada,that X-band looks pretty interesting though it seems to have quite a bit of "speckle" or is the surface of that area really that rough?Cheers, Holger

[Guest vlada stoje]

Hi Holger,yes I also see the speckles in the 1arc sec X-band SRTM, but there are visible perhaps the detailed shapes too. Sorry that for now these data are not public and also the coverage from the STS-99 flight was not complete due to the narrow swath of the X-band antenna. Near to the border parallels N60 and S56 the coverage could be quite complete thanks to the dense net of the Endeavour trajectories there. I don

[=Hollywood= 0]

>Hi Holger,>>I have here perhaps the final correction to the above offered>corrections for the current seamless 3 arc sec SRTM. After>observation of several another samples, it seems that there>are missing two data lines causing the positioning problem,>one vertical at Greenwich meridian>>>and the second horizontal, but not at the equator, but>surprisingly at the parallel N01>>>>So the correction for the coordinates depending at the>position on the Earth should be>>ULXMAP : = ULXMAP + sign(lon)*0.00041667 (west minus, east>plus)>>ULYMAP : = ULYMAP + sign( lat

[Guest vlada stoje]

Hi Dean,thanks for confirming that observations, actually the discussed deviation is quite small, some 45 to 64 m, but for us perfectionists this is important. I opened your data immediatelly in Global Mapper and the result was as expected, seamless data jumping in the NW direction.FSX is wonderful thing, I have to watch this piece of Earth from the bird perspective and did one decent flight from YIVL Inverell to YMOR Moree, very exotic country for Europeans!CheersVlada