[SECC] MicroDEM / HFTA

[K4SAV]

I don't usually use the DEM files since they are a lot more trouble.  
They are supposed to give better resolution for the terrain, but I 
haven't noticed a lot of difference, and higher resolution is not much 
help for HFTA.  HFTA will only accept 149 data points for each path so 
if you use small steps and high resolution you can't make the path long 
enough to be of any use.  I always use the NED files which never require 
merging and you only have to download one file.

As for the bad links,

For the link on page 53 try:
http://edcsns17.cr.usgs.gov/finder/finder_main.pl?dataset_name=NHAP

The link on page 55 no longer works as you can see from here
http://www.digitaldataservices.com/carto_mapdata.htm

If you use this link you can download DEMs by area names instead of 
having to use quad numbers.
http://data.geocomm.com/dem/demdownload.html

If you really want to use DEMs you need to check your location to see if 
you are near a quad boundary.  If so then you have to download the 
adjacent quads and go thru a merging procedure.  You put these files 
into the folder "mapdata/DEMs".  The merging is done by MicroDEM.  
MicroDEM can open the .TAR.gz file directly. 

If you use NEDs you download a gif file that you have to unpack, and put 
in the "mapdata/DEM" folder and then open the tif file that will be 
inside this gif file.

Jerry

Gordon wrote:

> I am trying to find the quad name for the 7.5 minute quadrangle. My 
> starting point is a powerpoint presentation from the web.
>
> <http://www.microham-usa.com/appnotes/Stacks%20Milford%20CT%202003.pdf>
>
> The links on page 53,54,55 don't seem to work.
> I did download a file according to page 56, 57.
>
>
> This should be the right file 1630688.DEM.SDTS.TXT  for Fairburn, GA 
> 30213
> Now that I have this file , I'm not sure what to do with it. Load it 
> into Microdem but where ?
>
> I need to go out when it gets daylight and get the gps readings near 
> the tower.
>
> 73 Gordon
>
>
>
>
>
>
>
> K4SAV wrote:
>
>> I'm not sure I qualify as an expert, but I will try.
>> If the question is why can't I download from the USGS website, the 
>> answer is they have been down.  They just came back on-line today.
>>
>> Jerry, K4SAV
>>
>> Macie, Gordon wrote:
>>
>>  
>>
>>> Do we have any MicroDEM / HFTA  users / experts our there. I could use
>>> some help
>>>
>>>
>>>
>>> Gordon N4LR
>>>
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>>>  
>>>
>>>     
>>
>>
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