shrug-l: Question du jour

Joe Noble jnoble@ttrs.org
Fri, 30 Sep 2005 13:06:20 -0400


This is a multi-part message in MIME format.

------_=_NextPart_001_01C5C5E1.47770CCA
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

I would like to suggest some sort of protocol that folks post their =
question, once, then those that have a possible solution contact the =
person directly not numerous e-mails to the entire user list.  After a =
solution has been decided, the original person posting the question =
could sum the solutions in one e-mail back to the board.  Sorry but my =
e-mail has been looking like a GIS chat room as of late.  Joe

=20

Joe Noble=20

GIS/IS Coordinator=20

Tall Timbers Research Station

850-893-4153  x-232

=20

________________________________

From: shrug-l-admin@lists.dep.state.fl.us =
[mailto:shrug-l-admin@lists.dep.state.fl.us] On Behalf Of Sykes, John
Sent: Friday, September 30, 2005 12:41 PM
To: Geographic Systems LLC; shrug-L@lists.dep.state.fl.us
Subject: RE: shrug-l: Question du jour

=20

That's a good website.  From it I gather that if I want BOTH the =
distances and azimuths to my sampling locations from the site center to =
be the most accurate, the Azimuthal Equidistant projection is the best =
solution.

=20

I came up with part of the rest of your solution on my own, however, I'm =
having trouble rotating it through 360=B0.

=20

Another solution I thought of, is setting up the sector lines in an =
AutoCad file, then importing it into my map with a world file using the =
center point and the intersection of the first radial with the 10 mile =
buffer ring as the two points.

-- John=20

=20

=20

________________________________

From: Geographic Systems LLC [mailto:info@geographicsystems.com]=20
Sent: Friday, September 30, 2005 12:19 PM
To: Sykes, John
Subject: RE: shrug-l: Question du jour

Hi John,

=20

I will try to address the first part of your question (drawing lines out =
10 miles at 11.25 degree increments) and the last part (projections).  =
The second part of your question (rhumb line from site point to sampling =
location) may require more research.

=20

Projections - definitely play a part in spatial accuarcy.  My guess is =
you want a projection that preserves direction and distance.  A good =
place to start is the summary tables at the bottom of the map projection =
poster, http://erg.usgs.gov/isb/pubs/MapProjections/projections.html.=20

=20

Drawing lines of specific distance and angle.  You can do this manually =
when you sketch a line.  With Task set to Create New Feature and Target =
your line feature class, click the sketch tool (pencil) and click on the =
first point of your line.  Then right click away from the sketch and =
select "Direction" (or CTRL-A) specify an angle (0 being horizontal - ie =
"11.25") and then right click away from sketch again and select "Length" =
(or CTRL-L) ie "2mi" ("mi" for miles).  Or you can enter both the first =
time you right click by selecting "Direction/Length" (or CTRL-G).  Check =
out online help for "Creating segments using angles and lengths".

=20

Miguel Garriga

Geographic Systems, LLC

www.geographicsystems.com

407-261-0451

cel 321-279-6019

________________________________

From: shrug-l-admin@lists.dep.state.fl.us =
[mailto:shrug-l-admin@lists.dep.state.fl.us] On Behalf Of Sykes, John
Sent: Friday, September 30, 2005 10:21 AM
To: shrug-L@lists.dep.state.fl.us
Subject: shrug-l: Question du jour

=20

Since we (collectively) solved the question I had yesterday, here's a =
new one (put on your thinking caps - this one's tougher!).

Problem=20

When establishing environmental sampling locations around a site, we =
like to ensure that the various distance buffer rings are evenly covered =
(e.g., in this case:  "site boundary" to 2 miles, 2 - 5 miles and 5 - 10 =
miles.  This is simple to create and check with the standard multiple =
buffer tool in ArcToolbox.

However, we also like to check that the 16 compass sectors around the =
site have also been evenly covered*.  These 22-1/2=B0 sectors are =
centered on N, NNE, NE, ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, =
NW and NNW.

So, what I would like to do is to create these sectors visually, by =
drawing a line from the origin (an arbitrary "center" point on the site) =
out to 10 miles starting at 11-1/4=B0 compass heading, then rotate =
around 22-1/2=B0 and draw a line, until the 16 sectors are visually =
defined.

Any suggestions as how this can be done (easily)?  Previously, when =
doing this in AutoCad, I used a radial copy command.  I haven't noticed =
a similar command in ArcGIS.

Finally, once the sampling location is selected (and the lat/long of =
that location determined), we need to be able to determine and list the =
distance and azimuth (rhumb line) from that arbitrary "center" point on =
the site to the sampling location and put it into the sampling location =
attributes table (in the past, I've done this using the NGS "Inverse" =
program [fudging the rhumb line from the great circle azimuths] using a =
batch file input/output) for atmospheric dispersion modeling.  However, =
I don't see any easy way to do this with ArcInfo (especially on a batch =
file basis).  Any suggestions?

Finally, food for thought -- How does the projection being used effect =
the accuracy of all of this?  Normally we use Albers (equal area) or =
Mercator (which gives the most accurate rhumb lines), but is there a =
better projection to use to obtain accurate distances & azimuths?  I =
understand from the reading I've done that these functions may be rather =
projection-sensitive.

-- John=20

*Sometimes if there is a prevailing wind bias, we'll bias our sampling =
locations to that prevailing wind direction, but in the current case =
there is no strong prevailing wind direction - the annual wind rose =
shows an almost random 360=B0pattern.


------_=_NextPart_001_01C5C5E1.47770CCA
Content-Type: text/html;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

<html xmlns:v=3D"urn:schemas-microsoft-com:vml" =
xmlns:o=3D"urn:schemas-microsoft-com:office:office" =
xmlns:w=3D"urn:schemas-microsoft-com:office:word" =
xmlns=3D"http://www.w3.org/TR/REC-html40">

<head>
<meta http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<meta name=3DGenerator content=3D"Microsoft Word 11 (filtered medium)">
<!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]-->
<title>Question du jour</title>
<style>
<!--
 /* Font Definitions */
 @font-face
	{font-family:Tahoma;
	panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
	{font-family:"Monotype Corsiva";
	panose-1:3 1 1 1 1 2 1 1 1 1;}
 /* Style Definitions */
 p.MsoNormal, li.MsoNormal, div.MsoNormal
	{margin:0in;
	margin-bottom:.0001pt;
	font-size:12.0pt;
	font-family:"Times New Roman";}
a:link, span.MsoHyperlink
	{color:blue;
	text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
	{color:purple;
	text-decoration:underline;}
p.MsoAutoSig, li.MsoAutoSig, div.MsoAutoSig
	{margin:0in;
	margin-bottom:.0001pt;
	font-size:12.0pt;
	font-family:"Times New Roman";}
p
	{mso-margin-top-alt:auto;
	margin-right:0in;
	mso-margin-bottom-alt:auto;
	margin-left:0in;
	font-size:12.0pt;
	font-family:"Times New Roman";}
span.EmailStyle18
	{mso-style-type:personal;
	font-family:Arial;
	color:navy;}
span.EmailStyle20
	{mso-style-type:personal-reply;
	font-family:Arial;
	color:navy;}
@page Section1
	{size:8.5in 11.0in;
	margin:1.0in 1.25in 1.0in 1.25in;}
div.Section1
	{page:Section1;}
-->
</style>

</head>

<body lang=3DEN-US link=3Dblue vlink=3Dpurple>

<div class=3DSection1>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>I would like to suggest some sort =
of
protocol that folks post their question, once, then those that have a =
possible
solution contact the person directly not numerous e-mails to the entire =
user
list.=A0 After a solution has been decided, the original person posting =
the
question could sum the solutions in one e-mail back to the board.=A0 =
Sorry but my
e-mail has been looking like a GIS chat room as of late.=A0 =
Joe<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<div>

<p class=3DMsoAutoSig><font size=3D3 color=3Dnavy face=3D"Times New =
Roman"><span
style=3D'font-size:12.0pt;color:navy'>Joe Noble =
<o:p></o:p></span></font></p>

<p class=3DMsoAutoSig><font size=3D3 color=3Dnavy face=3D"Times New =
Roman"><span
style=3D'font-size:12.0pt;color:navy'>GIS/IS Coordinator =
<o:p></o:p></span></font></p>

<p class=3DMsoAutoSig><font size=3D3 color=3Dnavy face=3D"Times New =
Roman"><span
style=3D'font-size:12.0pt;color:navy'>Tall Timbers Research =
Station<o:p></o:p></span></font></p>

<p class=3DMsoAutoSig><font size=3D3 color=3Dnavy face=3D"Times New =
Roman"><span
style=3D'font-size:12.0pt;color:navy'>850-893-4153=A0 =
x-232<o:p></o:p></span></font></p>

</div>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<div>

<div class=3DMsoNormal align=3Dcenter style=3D'text-align:center'><font =
size=3D3
face=3D"Times New Roman"><span style=3D'font-size:12.0pt'>

<hr size=3D2 width=3D"100%" align=3Dcenter tabindex=3D-1>

</span></font></div>

<p class=3DMsoNormal><b><font size=3D2 face=3DTahoma><span =
style=3D'font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font =
size=3D2
face=3DTahoma><span style=3D'font-size:10.0pt;font-family:Tahoma'>
shrug-l-admin@lists.dep.state.fl.us
[mailto:shrug-l-admin@lists.dep.state.fl.us] <b><span =
style=3D'font-weight:bold'>On
Behalf Of </span></b>Sykes, John<br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> Friday, September =
30, 2005
12:41 PM<br>
<b><span style=3D'font-weight:bold'>To:</span></b> Geographic Systems =
LLC;
shrug-L@lists.dep.state.fl.us<br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> RE: shrug-l: =
Question du
jour</span></font><o:p></o:p></p>

</div>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D4 color=3Dblue face=3DArial><span =
style=3D'font-size:
13.5pt;font-family:Arial;color:blue'>That's a good website.&nbsp; From =
it I
gather that if I want BOTH the distances and azimuths to my sampling =
locations
from the site center to be the most accurate, the Azimuthal Equidistant
projection is the best solution.</span></font><o:p></o:p></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'>&nbsp;<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D4 color=3Dblue face=3DArial><span =
style=3D'font-size:
13.5pt;font-family:Arial;color:blue'>I came up with part of the rest of =
your
solution on my own, however, I'm having trouble rotating it through =
360=B0.</span></font><o:p></o:p></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'>&nbsp;<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D4 color=3Dblue face=3DArial><span =
style=3D'font-size:
13.5pt;font-family:Arial;color:blue'>Another solution I thought of, is =
setting
up the sector lines in an AutoCad file, then importing it into my map =
with a
world file using the center point and the intersection of the first =
radial with
the 10 mile buffer ring as the two points.</span></font><o:p></o:p></p>

<p><b><font size=3D5 face=3D"Monotype Corsiva"><span =
style=3D'font-size:18.0pt;
font-family:"Monotype Corsiva";font-weight:bold'>-- =
John</span></font></b> <o:p></o:p></p>

<div>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'>&nbsp;<o:p></o:p></span></font></p>

</div>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'><o:p>&nbsp;</o:p></span></font></p>

<div class=3DMsoNormal align=3Dcenter style=3D'text-align:center'><font =
size=3D3
face=3D"Times New Roman"><span style=3D'font-size:12.0pt'>

<hr size=3D2 width=3D"100%" align=3Dcenter tabIndex=3D-1>

</span></font></div>

<p class=3DMsoNormal style=3D'margin-bottom:12.0pt'><b><font size=3D2 =
face=3DTahoma><span
style=3D'font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</spa=
n></font></b><font
size=3D2 face=3DTahoma><span =
style=3D'font-size:10.0pt;font-family:Tahoma'>
Geographic Systems LLC [mailto:info@geographicsystems.com] <br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> Friday, September =
30, 2005
12:19 PM<br>
<b><span style=3D'font-weight:bold'>To:</span></b> Sykes, John<br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> RE: shrug-l: =
Question du
jour</span></font><o:p></o:p></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Hi =
John,<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>I will try to address the first =
part of
your question (drawing lines out 10 miles at 11.25 degree increments) =
and the
last part (projections). &nbsp;The second part of your question (rhumb =
line
from site point to sampling location) may require more =
research.<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Projections &#8211; definitely play =
a part
in spatial accuarcy. &nbsp;My guess is you want a projection that =
preserves
direction and distance.&nbsp; A good place to start is the summary =
tables at
the bottom of the map projection poster, <a
href=3D"http://erg.usgs.gov/isb/pubs/MapProjections/projections.html">htt=
p://erg.usgs.gov/isb/pubs/MapProjections/projections.html</a>.
<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Drawing lines of specific distance =
and
angle. &nbsp;You can do this manually when you sketch a line. &nbsp;With =
Task
set to Create New Feature and Target your line feature class, click the =
sketch
tool (pencil) and click on the first point of your line.&nbsp; Then =
right click
away from the sketch and select &#8220;Direction&#8221; (or CTRL-A) =
specify an
angle (0 being horizontal &#8211; ie &#8220;11.25&#8221;) and then right =
click
away from sketch again and select &#8220;Length&#8221; (or CTRL-L) ie
&#8220;2mi&#8221; (&#8220;mi&#8221; for miles). &nbsp;Or you can enter =
both the
first time you right click by selecting &#8220;Direction/Length&#8221; =
(or
CTRL-G).&nbsp; Check out online help for &#8220;Creating segments using =
angles
and lengths&#8221;.<o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p>

<div>

<div>

<p class=3DMsoNormal><em><i><font size=3D2 color=3Dnavy =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial;color:navy'>Miguel =
Garriga</span></font></i></em><font
color=3Dnavy><span style=3D'color:navy'><o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Geographic Systems, =
LLC</span></font><font
color=3Dnavy><span style=3D'color:navy'><o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><a =
href=3D"http://www.geographicsystems.com">www.geographicsystems.com</a></=
span></font><font
color=3Dnavy><span style=3D'color:navy'><o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>407-261-0451</span></font><font
color=3Dnavy><span style=3D'color:navy'><o:p></o:p></span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>cel =
321-279-6019</span></font><o:p></o:p></p>

</div>

</div>

<div>

<div class=3DMsoNormal align=3Dcenter style=3D'text-align:center'><font =
size=3D3
face=3D"Times New Roman"><span style=3D'font-size:12.0pt'>

<hr size=3D2 width=3D"100%" align=3Dcenter tabIndex=3D-1>

</span></font></div>

<p class=3DMsoNormal><b><font size=3D2 face=3DTahoma><span =
style=3D'font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font =
size=3D2
face=3DTahoma><span style=3D'font-size:10.0pt;font-family:Tahoma'>
shrug-l-admin@lists.dep.state.fl.us
[mailto:shrug-l-admin@lists.dep.state.fl.us] <b><span =
style=3D'font-weight:bold'>On
Behalf Of </span></b>Sykes, John<br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> Friday, September =
30, 2005
10:21 AM<br>
<b><span style=3D'font-weight:bold'>To:</span></b> =
shrug-L@lists.dep.state.fl.us<br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> shrug-l: =
Question du jour</span></font><o:p></o:p></p>

</div>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'><o:p>&nbsp;</o:p></span></font></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>Since
we (collectively) solved the question I had yesterday, here's a new one =
(put on
your thinking caps - this one's tougher!).</span></font><o:p></o:p></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>Problem</span></font>
<o:p></o:p></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>When
establishing environmental sampling locations around a site, we like to =
ensure
that the various distance buffer rings are evenly covered (e.g., in this
case:&nbsp; &quot;site boundary&quot; to 2 miles, 2 - 5 miles and 5 - 10
miles.&nbsp; This is simple to create and check with the standard =
multiple
buffer tool in ArcToolbox.</span></font><o:p></o:p></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>However,
we also like to check that the 16 compass sectors around the site have =
also
been evenly covered*.&nbsp; These 22-1/2=B0 sectors are centered on N, =
NNE, NE,
ENE, E, ESE, SE, SSE, S, SSW, SW, WSW, W, WNW, NW and =
NNW.</span></font><o:p></o:p></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>So,
what I would like to do is to create these sectors visually, by drawing =
a line
from the origin (an arbitrary &quot;center&quot; point on the site) out =
to 10
miles starting at 11-1/4=B0 compass heading, then rotate around =
22-1/2=B0 and draw
a line, until the 16 sectors are visually =
defined.</span></font><o:p></o:p></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>Any
suggestions as how this can be done (easily)?&nbsp; Previously, when =
doing this
in AutoCad, I used a radial copy command.&nbsp; I haven't noticed a =
similar
command in ArcGIS.</span></font><o:p></o:p></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>Finally,
once the sampling location is selected (and the lat/long of that =
location
determined), we need to be able to determine and list the distance and =
azimuth
(rhumb line) from that arbitrary &quot;center&quot; point on the site to =
the
sampling location and put it into the sampling location attributes table =
(in
the past, I've done this using the NGS &quot;Inverse&quot; program =
[fudging the
rhumb line from the great circle azimuths] using a batch file =
input/output) for
atmospheric dispersion modeling.&nbsp; However, I don't see any easy way =
to do
this with ArcInfo (especially on a batch file basis).&nbsp; Any =
suggestions?</span></font><o:p></o:p></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>Finally,
food for thought -- How does the projection being used effect the =
accuracy of
all of this?&nbsp; Normally we use Albers (equal area) or Mercator =
(which gives
the most accurate rhumb lines), but is there a better projection to use =
to
obtain accurate distances &amp; azimuths?&nbsp; I understand from the =
reading
I've done that these functions may be rather =
projection-sensitive.</span></font><o:p></o:p></p>

<p><b><font size=3D5 face=3D"Monotype Corsiva"><span =
style=3D'font-size:18.0pt;
font-family:"Monotype Corsiva";font-weight:bold'>-- =
John</span></font></b> <o:p></o:p></p>

<p><font size=3D4 face=3DArial><span =
style=3D'font-size:13.5pt;font-family:Arial'>*Sometimes
if there is a prevailing wind bias, we'll bias our sampling locations to =
that
prevailing wind direction, but in the current case there is no strong
prevailing wind direction - the annual wind rose shows an almost random
360=B0pattern.</span></font><o:p></o:p></p>

</div>

</body>

</html>

------_=_NextPart_001_01C5C5E1.47770CCA--