Various software models may have this feature but LinkPlanner does not. PathLoss and IQ.Link will take whatever you put in them - if you have both data sets (SRTM, NED) you can easily run profiles with each set
-----Original Message----- From: Af [mailto:af-boun...@afmug.com] On Behalf Of Adam Moffett Sent: Wednesday, July 22, 2015 11:31 AM To: af@afmug.com Subject: Re: [AFMUG] NED vs SRTM Does any of the RF modeling software automatically compare NED with SRTM to extrapolate clutter height? It seems like it would be a straightforward feature to add. On 7/22/2015 8:35 AM, Hardy, Tim wrote: > Another point to remember: > > The end points of an SRTM profile sometimes need to be adjusted downwards (or > at the very least, verified) to account for the morphology above terrain that > may have been included in the SRTM data. > > -----Original Message----- > From: Af [mailto:af-boun...@afmug.com] On Behalf Of Brian Webster > Sent: Tuesday, July 21, 2015 11:22 PM > To: af@afmug.com > Subject: Re: [AFMUG] NED vs SRTM > > NED is the national elevation dataset and is based on actual ground elevation > data and digitized topo maps. > > SRTM is a combination of RADAR and LIDAR data from the shuttle missions. They > do not reflect actual ground elevation, they are a processed echo return of > whatever radar and LIDAR returns that were received on the shuttle. > > The source of the data should also be known as to the resolution. SRTM data > was published at 30 meter resolution meaning the hard data points are spaced > at 30 meter intervals. NED data is available in various resolutions the most > common nationwide being 1/3 arc second or 10 meter resolution or actual data > points every 10 meters. This produces a much more accurate terrain model > which in turn creates much more accurate RF propagation information. > > I have attached a real rough paper with images that illustrate the various > differences in terrain data and resolution. > > > > Thank You, > Brian Webster > www.wirelessmapping.com > www.Broadband-Mapping.com > > > -----Original Message----- > From: Af [mailto:af-boun...@afmug.com] On Behalf Of Adam Moffett > Sent: Tuesday, July 21, 2015 6:19 PM > To: af@afmug.com > Subject: [AFMUG] NED vs SRTM > > If there's a 5 meter discrepancy between USGS National Elevation Data and the > Shuttle Radar Topography Mission, who would you trust? Would you bet $500 on > it? > > In this case, with NED I'll have LOS on a backhaul, and with SRTM I'm > in the woods. I'm under the impression that SRTM sometimes gets you > treetops rather than the ground. If I'm wrong I have alternate paths, > but I'd have to pay for a new PCN....so it really is a $500 bet. :) >
