shrug-l: Question du jour

Nonie Castro nonie_castro@coxtarget.com
Fri, 30 Sep 2005 13:17:16 -0400


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If we are taking a vote - I don't mind the back and forth in real time.=20


________________________________

	From: shrug-l-admin@lists.dep.state.fl.us =
[mailto:shrug-l-admin@lists.dep.state.fl.us] On Behalf Of Joe Noble
	Sent: Friday, September 30, 2005 1:06 PM
	To: Sykes, John; Geographic Systems LLC; shrug-L@lists.dep.state.fl.us
	Subject: RE: shrug-l: Question du jour
=09
=09

	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

=09
________________________________


	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

=09
________________________________


	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

=09
________________________________


	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.


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<BODY lang=3DEN-US vLink=3Dpurple link=3Dblue>
<DIV dir=3Dltr align=3Dleft><FONT face=3D"Trebuchet MS" size=3D2><SPAN=20
class=3D405321617-30092005>If we are taking a vote - I don't mind the =
back and=20
forth in real time. </SPAN></FONT></DIV><BR>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px =
solid; MARGIN-RIGHT: 0px">
  <DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft>
  <HR tabIndex=3D-1>
  <FONT face=3DTahoma size=3D2><B>From:</B> =
shrug-l-admin@lists.dep.state.fl.us=20
  [mailto:shrug-l-admin@lists.dep.state.fl.us] <B>On Behalf Of </B>Joe=20
  Noble<BR><B>Sent:</B> Friday, September 30, 2005 1:06 PM<BR><B>To:</B> =
Sykes,=20
  John; Geographic Systems LLC; =
shrug-L@lists.dep.state.fl.us<BR><B>Subject:</B>=20
  RE: shrug-l: Question du jour<BR></FONT><BR></DIV>
  <DIV></DIV>
  <DIV class=3DSection1>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I would =
like to=20
  suggest some sort of protocol that folks post their question, once, =
then those=20
  that have a possible solution contact the person directly not numerous =
e-mails=20
  to the entire user list.&nbsp; After a solution has been decided, the =
original=20
  person posting the question could sum the solutions in one e-mail back =
to the=20
  board.&nbsp; Sorry but my e-mail has been looking like a GIS chat room =
as of=20
  late.&nbsp; Joe<o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <DIV>
  <P class=3DMsoAutoSig><FONT face=3D"Times New Roman" color=3Dnavy =
size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt; COLOR: navy">Joe Noble =
<o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoAutoSig><FONT face=3D"Times New Roman" color=3Dnavy =
size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt; COLOR: navy">GIS/IS Coordinator=20
  <o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoAutoSig><FONT face=3D"Times New Roman" color=3Dnavy =
size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt; COLOR: navy">Tall Timbers Research=20
  Station<o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoAutoSig><FONT face=3D"Times New Roman" color=3Dnavy =
size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt; COLOR: navy">850-893-4153&nbsp;=20
  x-232<o:p></o:p></SPAN></FONT></P></DIV>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <DIV>
  <DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" =
align=3Dcenter><FONT=20
  face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">
  <HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>
  </SPAN></FONT></DIV>
  <P class=3DMsoNormal><B><FONT face=3DTahoma size=3D2><SPAN=20
  style=3D"FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">From:</SPAN></FONT></B><FONT=20
  face=3DTahoma size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">=20
  shrug-l-admin@lists.dep.state.fl.us=20
  [mailto:shrug-l-admin@lists.dep.state.fl.us] <B><SPAN=20
  style=3D"FONT-WEIGHT: bold">On Behalf Of </SPAN></B>Sykes, =
John<BR><B><SPAN=20
  style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, September 30, =
2005 12:41=20
  PM<BR><B><SPAN style=3D"FONT-WEIGHT: bold">To:</SPAN></B> Geographic =
Systems=20
  LLC; shrug-L@lists.dep.state.fl.us<BR><B><SPAN=20
  style=3D"FONT-WEIGHT: bold">Subject:</SPAN></B> RE: shrug-l: Question =
du=20
  jour</SPAN></FONT><o:p></o:p></P></DIV>
  <P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dblue size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; COLOR: blue; FONT-FAMILY: Arial">That's a =
good=20
  website.&nbsp; From it I gather that if I want BOTH the distances and =
azimuths=20
  to my sampling locations from the site center to be the most accurate, =
the=20
  Azimuthal Equidistant projection is the best=20
  solution.</SPAN></FONT><o:p></o:p></P>
  <P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt">&nbsp;<o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dblue size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; COLOR: blue; FONT-FAMILY: Arial">I came up =
with part=20
  of the rest of your solution on my own, however, I'm having trouble =
rotating=20
  it through 360=B0.</SPAN></FONT><o:p></o:p></P>
  <P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt">&nbsp;<o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dblue size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; COLOR: blue; FONT-FAMILY: Arial">Another =
solution I=20
  thought of, is setting up the sector lines in an AutoCad file, then =
importing=20
  it into my map with a world file using the center point and the =
intersection=20
  of the first radial with the 10 mile buffer ring as the two=20
  points.</SPAN></FONT><o:p></o:p></P>
  <P><B><FONT face=3D"Monotype Corsiva" size=3D5><SPAN=20
  style=3D"FONT-WEIGHT: bold; FONT-SIZE: 18pt; FONT-FAMILY: 'Monotype =
Corsiva'">--=20
  John</SPAN></FONT></B> <o:p></o:p></P>
  <DIV>
  <P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt">&nbsp;<o:p></o:p></SPAN></FONT></P></DIV>
  <P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" =
align=3Dcenter><FONT=20
  face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">
  <HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>
  </SPAN></FONT></DIV>
  <P class=3DMsoNormal style=3D"MARGIN-BOTTOM: 12pt"><B><FONT =
face=3DTahoma=20
  size=3D2><SPAN=20
  style=3D"FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">From:</SPAN></FONT></B><FONT=20
  face=3DTahoma size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">=20
  Geographic Systems LLC [mailto:info@geographicsystems.com] =
<BR><B><SPAN=20
  style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, September 30, =
2005 12:19=20
  PM<BR><B><SPAN style=3D"FONT-WEIGHT: bold">To:</SPAN></B> Sykes,=20
  John<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Subject:</SPAN></B> RE: =
shrug-l:=20
  Question du jour</SPAN></FONT><o:p></o:p></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Hi=20
  John,<o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I will try =
to address=20
  the first part of your question (drawing lines out 10 miles at 11.25 =
degree=20
  increments) and the last part (projections). &nbsp;The second part of =
your=20
  question (rhumb line from site point to sampling location) may require =
more=20
  research.<o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Projections =
=96=20
  definitely play a part in spatial accuarcy. &nbsp;My guess is you want =
a=20
  projection that preserves direction and distance.&nbsp; A good place =
to start=20
  is the summary tables at the bottom of the map projection poster, <A=20
  =
href=3D"http://erg.usgs.gov/isb/pubs/MapProjections/projections.html">htt=
p://erg.usgs.gov/isb/pubs/MapProjections/projections.html</A>.=20
  <o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Drawing =
lines of=20
  specific distance and angle. &nbsp;You can do this manually when you =
sketch a=20
  line. &nbsp;With Task set to Create New Feature and Target your line =
feature=20
  class, click the sketch tool (pencil) and click on the first point of =
your=20
  line.&nbsp; Then right click away from the sketch and select =
=93Direction=94 (or=20
  CTRL-A) specify an angle (0 being horizontal =96 ie =9311.25=94) and =
then right=20
  click away from sketch again and select =93Length=94 (or CTRL-L) ie =
=932mi=94 (=93mi=94=20
  for miles). &nbsp;Or you can enter both the first time you right click =
by=20
  selecting =93Direction/Length=94 (or CTRL-G).&nbsp; Check out online =
help for=20
  =93Creating segments using angles and =
lengths=94.<o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <DIV>
  <DIV>
  <P class=3DMsoNormal><EM><I><FONT face=3DArial color=3Dnavy =
size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Miguel=20
  Garriga</SPAN></FONT></I></EM><FONT color=3Dnavy><SPAN=20
  style=3D"COLOR: navy"><o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Geographic =
Systems,=20
  LLC</SPAN></FONT><FONT color=3Dnavy><SPAN=20
  style=3D"COLOR: navy"><o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><A=20
  =
href=3D"http://www.geographicsystems.com">www.geographicsystems.com</A></=
SPAN></FONT><FONT=20
  color=3Dnavy><SPAN style=3D"COLOR: navy"><o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: =
Arial">407-261-0451</SPAN></FONT><FONT=20
  color=3Dnavy><SPAN style=3D"COLOR: navy"><o:p></o:p></SPAN></FONT></P>
  <P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
  style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">cel=20
  321-279-6019</SPAN></FONT><o:p></o:p></P></DIV></DIV>
  <DIV>
  <DIV class=3DMsoNormal style=3D"TEXT-ALIGN: center" =
align=3Dcenter><FONT=20
  face=3D"Times New Roman" size=3D3><SPAN style=3D"FONT-SIZE: 12pt">
  <HR tabIndex=3D-1 align=3Dcenter width=3D"100%" SIZE=3D2>
  </SPAN></FONT></DIV>
  <P class=3DMsoNormal><B><FONT face=3DTahoma size=3D2><SPAN=20
  style=3D"FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">From:</SPAN></FONT></B><FONT=20
  face=3DTahoma size=3D2><SPAN style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Tahoma">=20
  shrug-l-admin@lists.dep.state.fl.us=20
  [mailto:shrug-l-admin@lists.dep.state.fl.us] <B><SPAN=20
  style=3D"FONT-WEIGHT: bold">On Behalf Of </SPAN></B>Sykes, =
John<BR><B><SPAN=20
  style=3D"FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, September 30, =
2005 10:21=20
  AM<BR><B><SPAN style=3D"FONT-WEIGHT: bold">To:</SPAN></B>=20
  shrug-L@lists.dep.state.fl.us<BR><B><SPAN=20
  style=3D"FONT-WEIGHT: bold">Subject:</SPAN></B> shrug-l: Question du=20
  jour</SPAN></FONT><o:p></o:p></P></DIV>
  <P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
  style=3D"FONT-SIZE: 12pt"><o:p>&nbsp;</o:p></SPAN></FONT></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">Since we =
(collectively) solved=20
  the question I had yesterday, here's a new one (put on your thinking =
caps -=20
  this one's tougher!).</SPAN></FONT><o:p></o:p></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">Problem</SPAN></FONT>=20
  <o:p></o:p></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">When establishing =
environmental=20
  sampling locations around a site, we like to ensure that the various =
distance=20
  buffer rings are evenly covered (e.g., in this case:&nbsp; "site =
boundary" to=20
  2 miles, 2 - 5 miles and 5 - 10 miles.&nbsp; This is simple to create =
and=20
  check with the standard multiple buffer tool in=20
  ArcToolbox.</SPAN></FONT><o:p></o:p></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">However, we also like =
to check=20
  that the 16 compass sectors around the site have also been evenly=20
  covered*.&nbsp; These 22-1/2=B0 sectors are centered on N, NNE, NE, =
ENE, E, ESE,=20
  SE, SSE, S, SSW, SW, WSW, W, WNW, NW and =
NNW.</SPAN></FONT><o:p></o:p></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">So, what I would like =
to do is=20
  to create these sectors visually, by drawing a line from the origin =
(an=20
  arbitrary "center" point on the site) out to 10 miles starting at =
11-1/4=B0=20
  compass heading, then rotate around 22-1/2=B0 and draw a line, until =
the 16=20
  sectors are visually defined.</SPAN></FONT><o:p></o:p></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">Any suggestions as how =
this can=20
  be done (easily)?&nbsp; Previously, when doing this in AutoCad, I used =
a=20
  radial copy command.&nbsp; I haven't noticed a similar command in=20
  ArcGIS.</SPAN></FONT><o:p></o:p></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">Finally, once the =
sampling=20
  location is selected (and the lat/long of that location determined), =
we need=20
  to be able to determine and list the distance and azimuth (rhumb line) =
from=20
  that arbitrary "center" point on the site to the sampling location and =
put it=20
  into the sampling location attributes table (in the past, I've done =
this using=20
  the NGS "Inverse" program [fudging the rhumb line from the great =
circle=20
  azimuths] using a batch file input/output) for atmospheric dispersion=20
  modeling.&nbsp; However, I don't see any easy way to do this with =
ArcInfo=20
  (especially on a batch file basis).&nbsp; Any=20
  suggestions?</SPAN></FONT><o:p></o:p></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">Finally, food for =
thought -- How=20
  does the projection being used effect the accuracy of all of =
this?&nbsp;=20
  Normally we use Albers (equal area) or Mercator (which gives the most =
accurate=20
  rhumb lines), but is there a better projection to use to obtain =
accurate=20
  distances &amp; azimuths?&nbsp; I understand from the reading I've =
done that=20
  these functions may be rather=20
  projection-sensitive.</SPAN></FONT><o:p></o:p></P>
  <P><B><FONT face=3D"Monotype Corsiva" size=3D5><SPAN=20
  style=3D"FONT-WEIGHT: bold; FONT-SIZE: 18pt; FONT-FAMILY: 'Monotype =
Corsiva'">--=20
  John</SPAN></FONT></B> <o:p></o:p></P>
  <P><FONT face=3DArial size=3D4><SPAN=20
  style=3D"FONT-SIZE: 13.5pt; FONT-FAMILY: Arial">*Sometimes if there is =
a=20
  prevailing wind bias, we'll bias our sampling locations to that =
prevailing=20
  wind direction, but in the current case there is no strong prevailing =
wind=20
  direction - the annual wind rose shows an almost random=20
  =
360=B0pattern.</SPAN></FONT><o:p></o:p></P></DIV></BLOCKQUOTE></BODY></HT=
ML>

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