Thursday, June 05, 2008

SPLAT! 1.2.2 for Windows is ready

I ran into some problems caused by the compiler trying to "optimize" some of the math routines, so after a lot of troubleshooting, I lowered the optimization level to -O1. Version 1.2.2 for Windows is ready to use. Please let me know if you have any problems. If you are wondering what SPLAT! is, see this previous post.


L said...

This is wonderful!!! Thanks for your efforts.

When used for shorter links (less than 5 miles) it makes the terrain or path profile look very jagged.

Is it possible to adjust the output of the (p)GNUplot to pre-define the axis scale or scale of the output grid?



John McMellen said...

I think the determining factor is the resolution of the terrain data. SPLAT uses 1 degree square areas that are 3 arc second resolution, so on a very short path, you're just not going to see as much detail in the terrain. I don't know a lot about GNUplot, but I don't think scaling will help this problem.

You could also email John Magliacane and see what he thinks, but that is my impression.

L said...

My apologies, I may have pointed you in the wrong direction...

With shorter links we actually see TOO MUCH detail and was hoping to be able to "zoom" it out as not to look as drastic.

John McMellen said...

I follow you now...

It would probably be possible to modify the source code of SPLAT! to save the raw Gnuplot input as a file and then run it through Gnuplot as a second step, passing it whatever parameters are available that might help. Again, I don't know much about using Gnuplot, so I don't know what those parameters would be.

Is that a feature you would like to see?

L said...


It would be a great feature to be able to "zoom" in/out or set the grid size or X and Y coordinates especially on shorter links.

Additionally, would like to be able to overlay potential obstructions (trees, buildings, etc) to simulate environments.

Thank you for the help and your efforts.

Mr. said...

John, I appreciate the work you have put into SPLAT. I just ran accross this software last week and I'm NOT tech savy. I'm actually wanting to use this software to plot VHF two-way coverage. Would this software meet those needs? Would you mind calling me to discuss? If so, please email me at .


John McMellen said...


I was able to comment out the lines that delete the temporary gnuplot files used for the rendering. After running a profile in SPLAT!, you can modify these left over files and generate plots based on your personal scale preference. You can modify the source code and recompile yourself, or I could send you the modified executable if you want. Let me know.

Sam said...

Hi John, this seems like a really great product if i could get it to work. i have been able to run it and put tower locations etc, but i'm having trouble converting SRTM data to sdf format. I run the following and it gives me an error

C:\splat-1.2.2>srtm2sdf.exe -N40W083.hgt
*** Error: "-N40W083.hgt" doesn't look like a valid .hgt SRTM filename.

John McMellen said...

Sam, sorry to hear you are having problems. Here is a few examples of using the srtm2sdf utility (just run srtm2sdf.exe with no options and you should see this explanation).

srtm2sdf N40W074.hgt
srtm2sdf -d /cdrom/sdf N40W074.hgt
srtm2sdf -d /dev/null N40W074.hgt
srtm2sdf -n -5 N40W074.hgt

I don't know if it was possibly only a typo in your comment, but I noticed in the example you provided that the name of the HGT file has a dash on the front of it (i.e. -N40W083.hgt). I don't think the dash is supposed to be there, and I have not seen any HGT files before that include a dash in the name. The correct command would be:
srtm2sdf N40W083.hgt

You might try this if you haven't already. Let me know if you still are having problems.

Sam said...

Thank you so much, something made me think the dash needed to be in front of the file :( sorry

It works now

Kathy said...

I would like to make changes. Could I get a copy of your source code?

John McMellen said...

Dan, the source code is included in the zip file along with the executable. You can download it from the link in the post.

Pablo said...

Hello John!

I've using SPLAT! for a while and I think it's great, but I hadn't heard about your port until now. Great work! (for me, SPLAT! is the main reason to use Linux at work, so this will be very useful, thanks!)

I wonder if you're planning to compile the new version (SPLAT! Version 1.2.3 was released on July 30, 2008). That would be great, in order to enjoy the "bug-fix and accuracy improvement" of the release.

Thank you again!

John McMellen said...


I have the code, I haven't been able to generate the Windows build for 1.2.3 yet. I have been so busy at work the past couple of weeks that I haven't had time. I will try to get it out the door ASAP

John McMellen said...

Pablo and all,

SPLAT! 1.2.3 for Win32 is ready for download. Sorry for the wait.

Hector said...


Thanks for making it possible for us Windows users to run SPLAT!
I hope you can help me understand the path loss output file: when I ran the program to get Longley-Rice coverage map, the resulting file had seven columns. I know the first five are Latitud, Longitude, azimuth, elevation and path loss figure... what are the remaining two columns?

John McMellen said...


I can't find any official documentation on these two columns. After looking at the source code, I would guess that column 6 is the path loss with the antenna pattern figured in, and column 7 is the field strength based on the ERP input.

You might send the program author an email for an official explanation. It may be that the documentation hasn't been updated to reflect this new feature.