Re: [Xastir] Correct command?

[Steve/WM5Z]

Curt, WE7U wrote:

On Sun, 26 Oct 2008, Steve/WM5Z wrote:


OK. I'll give it a try this evening. Thanks Alex.


Make sure that if you use backslashes, there's nothing else on the
end of each line.  A backslash at the END of each line is the signal
to the shell to continue the command on the next line.  A possible
gotcha' there.


OK, I spoke to soon. The files that were generated are still empty.

I did follow the destructions. So what went wrong? BTW, I am using the 
latest download from the site with a 2008 date code. They didn't by 
chance change the fields, did they???


Steve/WM5Z

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Re: [Xastir] Correct command?

[Steve/WM5Z]

Alex Carver wrote:

The backslashes allow that command to be split across multiple lines.  If you 
want to use only one line, don't use the backslashes.

Just copy it as a three line command.  Copy and paste the first line including the 
backslash (\) on the end, then hit enter.  Repeat for each line.  And, yes, the 
> should be in there.


--- On Sun, 10/26/08, Steve/WM5Z <[EMAIL PROTECTED]> wrote:

  

From: Steve/WM5Z <[EMAIL PROTECTED]>
Subject: [Xastir] Correct command?
To: "Xastir - APRS client software discussion" 
Date: Sunday, October 26, 2008, 10:58 AM
In "README.maps" in the area discussing GNIS
files, you talk about 
filtering the POP_PLACES.gnis file to strip the smaller
communities. You 
give the instruction as;


awk -F\| '{if ($17 > 1000) print
$0}' \
/usr/local/share/xastir/GNIS/0pop_places.gnis
\
   


/usr/local/share/xastir/GNIS/0pop_places_over_1k.gnis
  

which I am assuming is to be entered as one line. My
problem is, when I 
cut and paste the command I can't figure out am I
supposed to have all 
the spaces between each line? If not, do I splice
"\/" or is there a 
space in there. Also is the > in the third line supposed

to be there?

I have tried and tried, but can't get the command to
work. It will make 
the file 0pop... but it is empty.


I want to make a couple of files. One filtering out the
less than 1000 
and one to make a file for less than 10,000.


Steve/WM5Z
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OK, that works. But now they quit showing up above a zoom level of about 
1000. Where do I change that at?


Steve/WM5Z
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Re: [Xastir] Has anyone had any experience with converting digital elevation models to shapefiles?

[Brad Douglas]

On Sun, 2008-10-26 at 09:54 -0600, Tom Russo wrote:
> On Sun, Oct 26, 2008 at 09:30:01AM -0500, we recorded a bogon-computron 
> collision of the <[EMAIL PROTECTED]> flavor, containing:
> > Converting Digital Elevation Models To Shapefile/DXF Contours
> > Published at December 20, 2007 in DEM, GIS and Garmin.
> > 
> > 
> > http://freegeographytools.com/2007/converting-digital-elevation-models-to-shapefiledxf-contours
> >  
> > 
> > 
> > I had a note from Curt in July, 2007, that Xastir doesn't support DEM file
> > format.  But if these were converted to shapefiles, should I be able to use
> > them?
> 
> Yes.  
> 
> There are plenty of tools to do this, including "gdal_contour" (a part of the
> GDAL suite).  

First, DEM is not a file format.  DEMs can be represented in numerous
formats (shp, tiff, etc).

The GDAL tools are very simplistic, but they'll get the basic job done.
If you want an accurate representation of the DEM, I would recommend
getting familiar with GRASS GIS.  At a minimum, you'll learn how to
correctly deal with different/conflicting datum/projections.

I put together a tutorial on this some time ago that was geared towards
Xastir users.  Should still be somewhere on the GRASS site.


-- 
73, de Brad KB8UYR/6 

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Re: [Xastir] Has anyone had any experience with converting digital elevation models to shapefiles?

[Tom Russo]

On Sun, Oct 26, 2008 at 06:05:54PM -0500, we recorded a bogon-computron 
collision of the <[EMAIL PROTECTED]> flavor, containing:
> Thanks, Tom..
> 
> I guessed you probably had but I didn't guess gdal!
> 
> So I (apparently) successfully installed the gdal utilities.  For an 
> example in the documentation, they show:
> gdal_contour -a elev dem.tif contour.shp -i 10.0
> 
> Is that a good set of options?  

Depends.  

The interval is in whatever units the DEM is in.  If that's in feet (as some
are) then you get 10 foot intervals with those options, which might not be
what you want.

> Don't you need to put in a base 
> elevation or something?  

Not really necessary, but you can.  With the arguments in the example command
line, it'll generate contours at 0,10,20,30, etc.  And so if your DEM only
has values between 5000 and 1, you'll get only 5000,5010,5020,etc.

You can specify a base elevation with the "-off" option, and it'll start
counting from there.  Otherwise it starts counting from 0.

> Are the contour lines labels with elevation?  

Only if you specify the "-a " option to give it an attribute name.  The
example command line has "-a elev" so the shapefile will have an attribute
called "elev" with the elevation of that line.

>I 
> don't understand the -3d, -inodata, or -snodata they are not needed 
> for the typical USGS dem?

You can probably ignore most of those.  Raster data, since it is always 
rectangular but might only have legitimate values for some other shape (say,
a rotated rectangle or other distorted outline), must have some value to
represent the fact that some pixel has no valid data.  

If you do a gdalinfo on the DEM, you'll see that the DEM format has information
in it that tells GDAL what the "no data" value is, so you needn't specify it.
"-3d" will create a 3-D shapefile with X,Y, and Z values at each point instead
of just X,Y.  For Xastir, you don't need that (and it is only relatively 
recently that xastir didn't just core dump when given a 3-d shapefile).

> Any other clues as my DEM downloads?

Nope.  Just make sure you know what units the DEM is in.  I've seen 'em with 
elevations in feet and with elevations in meters.

-- 
Tom RussoKM5VY   SAR502   DM64ux  http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236 AHTB#1 http://kevan.org/brain.cgi?DDTNM
 "Argue for your limitations and sure enough, they're yours."  -- R. Bach



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Re: [Xastir] Has anyone had any experience with converting digital elevation models to shapefiles?

[Jim Tolbert]

Thanks, Tom..

I guessed you probably had but I didn't guess gdal!

So I (apparently) successfully installed the gdal utilities.  For an 
example in the documentation, they show:

gdal_contour -a elev dem.tif contour.shp -i 10.0

Is that a good set of options?  Don't you need to put in a base 
elevation or something?  Are the contour lines labels with elevation?  I 
don't understand the -3d, -inodata, or -snodata they are not needed 
for the typical USGS dem?


Any other clues as my DEM downloads?

Many thanx.. jt

Tom Russo wrote:

On Sun, Oct 26, 2008 at 09:30:01AM -0500, we recorded a bogon-computron collision of 
the <[EMAIL PROTECTED]> flavor, containing:
  

Converting Digital Elevation Models To Shapefile/DXF Contours
Published at December 20, 2007 in DEM, GIS and Garmin.


http://freegeographytools.com/2007/converting-digital-elevation-models-to-shapefiledxf-contours 



I had a note from Curt in July, 2007, that Xastir doesn't support DEM file
format.  But if these were converted to shapefiles, should I be able to use
them?



Yes.  


There are plenty of tools to do this, including "gdal_contour" (a part of the
GDAL suite).  

  


--
Jim Tolbert

[EMAIL PROTECTED]

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Re: [Xastir] Correct command?

[Curt, WE7U]

On Sun, 26 Oct 2008, Steve/WM5Z wrote:


OK. I'll give it a try this evening. Thanks Alex.


Make sure that if you use backslashes, there's nothing else on the
end of each line.  A backslash at the END of each line is the signal
to the shell to continue the command on the next line.  A possible
gotcha' there.

--
Curt, WE7U. archer at eskimo dot com
http://www.eskimo.com/~archer
  Lotto:  A tax on people who are bad at math. - unknown
Windows:  Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me:  I picked the coordinate system!"
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Re: [Xastir] Correct command?

[Steve/WM5Z]

OK. I'll give it a try this evening. Thanks Alex.




Alex Carver wrote:

The backslashes allow that command to be split across multiple lines.  If you 
want to use only one line, don't use the backslashes.

Just copy it as a three line command.  Copy and paste the first line including the 
backslash (\) on the end, then hit enter.  Repeat for each line.  And, yes, the 
> should be in there.


--- On Sun, 10/26/08, Steve/WM5Z <[EMAIL PROTECTED]> wrote:

  

From: Steve/WM5Z <[EMAIL PROTECTED]>
Subject: [Xastir] Correct command?
To: "Xastir - APRS client software discussion" 
Date: Sunday, October 26, 2008, 10:58 AM
In "README.maps" in the area discussing GNIS
files, you talk about 
filtering the POP_PLACES.gnis file to strip the smaller
communities. You 
give the instruction as;


awk -F\| '{if ($17 > 1000) print
$0}' \
/usr/local/share/xastir/GNIS/0pop_places.gnis
\
   


/usr/local/share/xastir/GNIS/0pop_places_over_1k.gnis
  

which I am assuming is to be entered as one line. My
problem is, when I 
cut and paste the command I can't figure out am I
supposed to have all 
the spaces between each line? If not, do I splice
"\/" or is there a 
space in there. Also is the > in the third line supposed

to be there?

I have tried and tried, but can't get the command to
work. It will make 
the file 0pop... but it is empty.


I want to make a couple of files. One filtering out the
less than 1000 
and one to make a file for less than 10,000.


Steve/WM5Z
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Re: [Xastir] Has anyone had any experience with converting digital elevation models to shapefiles?

[Tom Russo]

On Sun, Oct 26, 2008 at 09:30:01AM -0500, we recorded a bogon-computron 
collision of the <[EMAIL PROTECTED]> flavor, containing:
> Converting Digital Elevation Models To Shapefile/DXF Contours
> Published at December 20, 2007 in DEM, GIS and Garmin.
> 
> 
> http://freegeographytools.com/2007/converting-digital-elevation-models-to-shapefiledxf-contours
>  
> 
> 
> I had a note from Curt in July, 2007, that Xastir doesn't support DEM file
> format.  But if these were converted to shapefiles, should I be able to use
> them?

Yes.  

There are plenty of tools to do this, including "gdal_contour" (a part of the
GDAL suite).  

-- 
Tom RussoKM5VY   SAR502   DM64ux  http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236 AHTB#1 http://kevan.org/brain.cgi?DDTNM
 "Argue for your limitations and sure enough, they're yours."  -- R. Bach



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Re: [Xastir] Correct command?

[Alex Carver]

The backslashes allow that command to be split across multiple lines.  If you 
want to use only one line, don't use the backslashes.

Just copy it as a three line command.  Copy and paste the first line including 
the backslash (\) on the end, then hit enter.  Repeat for each line.  And, yes, 
the > should be in there.


--- On Sun, 10/26/08, Steve/WM5Z <[EMAIL PROTECTED]> wrote:

> From: Steve/WM5Z <[EMAIL PROTECTED]>
> Subject: [Xastir] Correct command?
> To: "Xastir - APRS client software discussion" 
> Date: Sunday, October 26, 2008, 10:58 AM
> In "README.maps" in the area discussing GNIS
> files, you talk about 
> filtering the POP_PLACES.gnis file to strip the smaller
> communities. You 
> give the instruction as;
> 
> awk -F\| '{if ($17 > 1000) print
> $0}' \
> /usr/local/share/xastir/GNIS/0pop_places.gnis
> \
>
> >/usr/local/share/xastir/GNIS/0pop_places_over_1k.gnis
> 
> which I am assuming is to be entered as one line. My
> problem is, when I 
> cut and paste the command I can't figure out am I
> supposed to have all 
> the spaces between each line? If not, do I splice
> "\/" or is there a 
> space in there. Also is the > in the third line supposed
> to be there?
> 
> I have tried and tried, but can't get the command to
> work. It will make 
> the file 0pop... but it is empty.
> 
> I want to make a couple of files. One filtering out the
> less than 1000 
> and one to make a file for less than 10,000.
> 
> Steve/WM5Z
> ___
> Xastir mailing list
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[Xastir] Correct command?

[Steve/WM5Z]

In "README.maps" in the area discussing GNIS files, you talk about 
filtering the POP_PLACES.gnis file to strip the smaller communities. You 
give the instruction as;


   awk -F\| '{if ($17 > 1000) print $0}' \
   /usr/local/share/xastir/GNIS/0pop_places.gnis \
   >/usr/local/share/xastir/GNIS/0pop_places_over_1k.gnis

which I am assuming is to be entered as one line. My problem is, when I 
cut and paste the command I can't figure out am I supposed to have all 
the spaces between each line? If not, do I splice "\/" or is there a 
space in there. Also is the > in the third line supposed to be there?


I have tried and tried, but can't get the command to work. It will make 
the file 0pop... but it is empty.


I want to make a couple of files. One filtering out the less than 1000 
and one to make a file for less than 10,000.


Steve/WM5Z
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[Xastir] Has anyone had any experience with converting digital elevation models to shapefiles?

[Jim Tolbert]

Converting Digital Elevation Models To Shapefile/DXF Contours
Published at December 20, 2007 in DEM, GIS and Garmin.


http://freegeographytools.com/2007/converting-digital-elevation-models-to-shapefiledxf-contours 



I had a note from Curt in July, 2007, that Xastir doesn't support DEM file
format.  But if these were converted to shapefiles, should I be able to use
them?

I am thinking of shapefiles to use on top of aerial photos and with feature
shapefiles that will load faster than USGS topos.

Is there a better way or is there another source of elevation shapefiles 
that I

should be looking at?

Many thanx... jt

--
Jim Tolbert

[EMAIL PROTECTED]

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