I've been fooling with some shell scripts and the like.. I think I can automatically retrieve the right 1x1 degree chunks of SRTM data fairly well and then do the interpolation to build the profiles.
BTW, it won't be fast or small. the raw zip files are about 12Mbyte each and expand to about 26MB, so it will eat about 400 MB of your disk. (although you can delete the files when it's done) You're
That still sounds terrific to me, Jim. Lots of folks have fast enough internet connections to make that a viable option (mine is a fairly middle-of-the-road 5 Mbps), and if the process was sufficient
Jim - Even at a half an hour it's a real bargain. I would guess that many in the group would climb all over that opportunity and all in our group would thank you for your effort. It's what makes this
This sounds terrific, Jim, and will be a huge boon to the amateur radio community. One question: are you proposing to generate .pro files with data out to the full 50-60 miles, or just what HFTA can
Jim, this will be hugely valuable. As someone else has posted, maybe the profiles should have data restricted to just sufficient to feed HFTA. I'll add my congratulations on a great idea and what wil
HFTA will, as far as I know, work with almost any distance you choose. There seems to be a tacit belief that terrain points out beyond 5,000 or 6,000 meters are not worth bothering with, but I believ
The challenge is getting the SRTM data easily.. However it does look like a url of something like: http://dds.cr.usgs.gov/srtm/version2_1/SRTM3/Eurasia/N51E000.hgt.zip should work for the 3 arc secon
Just to what HFTA can deal with.. But rather than try to figure out which tiles to retrieve, you just retrieve the one you're in and the surrounding ones. (if you wanted to be clever, if your longitu
Jim, et al: I've always used the links provided on the Radio Mobile website to retrieve SRTM 1 arcsec data. It's been a while since I've retrieved any data (I have most of the local area here on my h
HFTA is limited to a total of 150 data points in the .pro file, including the tower base location. You can increase the total profile distance, but at the expense of also increasing the interval betw
Since I manually generate my own files I just jump to the next distance that represents a noticeable difference in height. HFTA simply assumes a linear incline/decline between data points so instead
i was thinking that once I run a profile to the edge of the dataset, I could go through and "prune" it with some simple algorithm. Obviously, you could eliminate ticks that vary less than some delta.
When a friend delivered 360 files of detailed radial profiles out to 100km from this site, it certainly concentrated the mind about the editing problem! This is messy terrain, with a lot of local det
If I recall correctly from some experiments a few years ago, there is an upper limit on the number of points you can profile, but not on their spacing. I think one of the last changes Dean made in HF
One of the things I wonder about is how much HFTA's 2-D computations differ from reality. At least, if we want to make HFTA happy, we only need a bulldozer with an infinitely thin blade. Got one righ
I suspect it is quite significant for some locations. There are folks here in the west who live in long, rather deep almost V-shaped canyons and I'd bet that skews their actual results quite a bit. 7
then we'll wait for someone to write a free raytracing code for HF that does 3D...<grin> This is why I like to run HFTA (and similar programs) with several different locations moving a bit. if you ha