shrug-l: question du jour input
Cyndi Brown
Cyndi Brown <cynmoon@earthlink.net>
Fri, 30 Sep 2005 16:00:59 -0400 (GMT-04:00)
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<DIV>My op is, if you dont want to read it delete it. ez! but some other pe=
ople may just benefit from the back and forth sharing, they may have simila=
r probs. <BR><BR><BR>-----Original Message----- <BR>From: lance.peterson@do=
t.state.fl.us <BR>Sent: Sep 30, 2005 1:21 PM <BR>To: shrug-L@lists.dep.stat=
e.fl.us <BR>Subject: RE: shrug-l: Question du jour <BR><BR><BR><FONT face=
=3Dsans-serif size=3D2>I like the back and forth also. This is really the b=
est GIS newsgroup I belong too.</FONT> <BR><BR><FONT face=3Dsans-serif size=
=3D2>At least we don't have a problem with spam.</FONT> <BR><FONT face=3Dsa=
ns-serif size=3D2><BR>Lance Peterson<BR></FONT><BR><BR><BR>
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<TD width=3D"40%"><FONT face=3Dsans-serif size=3D1><B>"Nonie Castro" <no=
nie_castro@coxtarget.com></B> </FONT><BR><FONT face=3Dsans-serif size=3D=
1>Sent by: shrug-l-admin@lists.dep.state.fl.us</FONT>=20
<P><FONT face=3Dsans-serif size=3D1>09/30/2005 01:17 PM</FONT> </P>
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<DIV align=3Dright><FONT face=3Dsans-serif size=3D1>To</FONT></DIV>
<TD vAlign=3Dtop><FONT face=3Dsans-serif size=3D1><shrug-L@lists.dep.sta=
te.fl.us></FONT>=20
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<DIV align=3Dright><FONT face=3Dsans-serif size=3D1>cc</FONT></DIV>
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<DIV align=3Dright><FONT face=3Dsans-serif size=3D1>Subject</FONT></DIV>
<TD vAlign=3Dtop><FONT face=3Dsans-serif size=3D1>RE: shrug-l: Question du =
jour</FONT></TR></TBODY></TABLE><BR>
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<TD></TR></TBODY></TABLE><BR></TR></TBODY></TABLE><BR><BR><BR><FONT face=3D=
"Trebuchet MS" size=3D2>If we are taking a vote - I don't mind the back and=
forth in real time. </FONT><BR><BR>
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<FONT face=3DTahoma size=3D2><B>From:</B> shrug-l-admin@lists.dep.state.fl.=
us [mailto:shrug-l-admin@lists.dep.state.fl.us] <B>On Behalf Of </B>Joe Nob=
le<B><BR>Sent:</B> Friday, September 30, 2005 1:06 PM<B><BR>To:</B> Sykes, =
John; Geographic Systems LLC; shrug-L@lists.dep.state.fl.us<B><BR>Subject:<=
/B> RE: shrug-l: Question du jour</FONT><FONT size=3D3><BR></FONT><BR><FONT=
face=3DArial color=3D#000080 size=3D2>I would like to suggest some sort of=
protocol that folks post their question, once, then those that have a poss=
ible solution contact the person directly not numerous e-mails to the entir=
e user list. After a solution has been decided, the original person p=
osting 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 lat=
e. Joe</FONT> <BR><FONT face=3DArial color=3D#000080 size=3D2> <=
/FONT> <BR><FONT face=3D"Times New Roman" color=3D#000080 size=3D3>Joe Nobl=
e </FONT><BR><FONT face=3D"Times New Roman" color=3D#000080 size=3D3>GIS/IS=
Coordinator </FONT><BR><FONT face=3D"Times New Roman" color=3D#000080 size=
=3D3>Tall Timbers Research Station</FONT> <BR><FONT face=3D"Times New Roman=
" color=3D#000080 size=3D3>850-893-4153 x-232</FONT> <BR><FONT face=
=3DArial color=3D#000080 size=3D2> </FONT>=20
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</DIV><BR><FONT face=3DTahoma size=3D2><B>From:</B> shrug-l-admin@lists.dep=
.state.fl.us [mailto:shrug-l-admin@lists.dep.state.fl.us] <B>On Behalf Of <=
/B>Sykes, John<B><BR>Sent:</B> Friday, September 30, 2005 12:41 PM<B><BR>To=
:</B> Geographic Systems LLC; shrug-L@lists.dep.state.fl.us<B><BR>Subject:<=
/B> RE: shrug-l: Question du jour</FONT> <BR><FONT face=3D"Times New Roman"=
size=3D3> </FONT> <BR><FONT face=3DArial color=3Dblue size=3D4>That's=
a good website. From it I gather that if I want BOTH the distances a=
nd azimuths to my sampling locations from the site center to be the most ac=
curate, the Azimuthal Equidistant projection is the best solution.</FONT> <=
BR><FONT face=3D"Times New Roman" size=3D3> </FONT> <BR><FONT face=3DA=
rial color=3Dblue size=3D4>I came up with part of the rest of your solution=
on my own, however, I'm having trouble rotating it through 360=B0.</FONT> =
<BR><FONT face=3D"Times New Roman" size=3D3> </FONT> <BR><FONT face=3D=
Arial color=3Dblue size=3D4>Another solution I thought of, is setting up th=
e sector lines in an AutoCad file, then importing it into my map with a wor=
ld file using the center point and the intersection of the first radial wit=
h the 10 mile buffer ring as the two points.</FONT>=20
<P><FONT face=3D"Monotype Corsiva" size=3D5><B>-- John</B></FONT><FONT face=
=3D"Times New Roman" size=3D3> </FONT><BR><FONT face=3D"Times New Roman" si=
ze=3D3> </FONT> <BR><FONT face=3D"Times New Roman" size=3D3> </FO=
NT>=20
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</DIV><BR><FONT face=3DTahoma size=3D2><B>From:</B> Geographic Systems LLC =
[mailto:info@geographicsystems.com] <B><BR>Sent:</B> Friday, September 30, =
2005 12:19 PM<B><BR>To:</B> Sykes, John<B><BR>Subject:</B> RE: shrug-l: Que=
stion du jour</FONT> <BR><FONT face=3DArial color=3D#000080 size=3D2>Hi Joh=
n,</FONT> <BR><FONT face=3DArial color=3D#000080 size=3D2> </FONT> <BR=
><FONT face=3DArial color=3D#000080 size=3D2>I will try to address the firs=
t part of your question (drawing lines out 10 miles at 11.25 degree increme=
nts) and the last part (projections). The second part of your questio=
n (rhumb line from site point to sampling location) may require more resear=
ch.</FONT> <BR><FONT face=3DArial color=3D#000080 size=3D2> </FONT> <B=
R><FONT face=3DArial color=3D#000080 size=3D2>Projections =96 definitely pl=
ay a part in spatial accuarcy. My guess is you want a projection that=
preserves direction and distance. A good place to start is the summa=
ry tables at the bottom of the map projection poster, </FONT><A href=3D"htt=
p://erg.usgs.gov/isb/pubs/MapProjections/projections.html"><FONT face=3DAri=
al color=3Dblue size=3D2><U>http://erg.usgs.gov/isb/pubs/MapProjections/pro=
jections.html</U></FONT></A><FONT face=3DArial color=3D#000080 size=3D2>. <=
/FONT><BR><FONT face=3DArial color=3D#000080 size=3D2> </FONT> <BR><FO=
NT face=3DArial color=3D#000080 size=3D2>Drawing lines of specific distance=
and angle. You can do this manually when you sketch a line. Wi=
th 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 =93Direction=94 (or CTRL-A=
) specify an angle (0 being horizontal =96 ie =9311.25=94) and then right c=
lick away from sketch again and select =93Length=94 (or CTRL-L) ie =932mi=
=94 (=93mi=94 for miles). Or you can enter both the first time you ri=
ght click by selecting =93Direction/Length=94 (or CTRL-G). Check out =
online help for =93Creating segments using angles and lengths=94.</FONT> <B=
R><FONT face=3DArial color=3D#000080 size=3D2> </FONT> <BR><FONT face=
=3DArial color=3D#000080 size=3D2><I>Miguel Garriga</I></FONT> <BR><FONT fa=
ce=3DArial color=3D#000080 size=3D2>Geographic Systems, LLC</FONT> <BR><A h=
ref=3D"http://www.geographicsystems.com/"><FONT face=3DArial color=3Dblue s=
ize=3D2><U>www.geographicsystems.com</U></FONT></A> <BR><FONT face=3DArial =
color=3D#000080 size=3D2>407-261-0451</FONT> <BR><FONT face=3DArial color=
=3D#000080 size=3D2>cel 321-279-6019</FONT>=20
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</DIV><BR><FONT face=3DTahoma size=3D2><B>From:</B> shrug-l-admin@lists.dep=
.state.fl.us [mailto:shrug-l-admin@lists.dep.state.fl.us] <B>On Behalf Of <=
/B>Sykes, John<B><BR>Sent:</B> Friday, September 30, 2005 10:21 AM<B><BR>To=
:</B> shrug-L@lists.dep.state.fl.us<B><BR>Subject:</B> shrug-l: Question du=
jour</FONT> <BR><FONT face=3D"Times New Roman" size=3D3> </FONT>=20
<P><FONT face=3DArial size=3D4>Since we (collectively) solved the question =
I had yesterday, here's a new one (put on your thinking caps - this one's t=
ougher!).</FONT>=20
<P><FONT face=3DArial size=3D4>Problem</FONT><FONT face=3D"Times New Roman"=
size=3D3> </FONT>
<P><FONT face=3DArial size=3D4>When establishing environmental sampling loc=
ations around a site, we like to ensure that the various distance buffer ri=
ngs are evenly covered (e.g., in this case: "site boundary" to 2 mile=
s, 2 - 5 miles and 5 - 10 miles. This is simple to create and check w=
ith the standard multiple buffer tool in ArcToolbox.</FONT>=20
<P><FONT face=3DArial size=3D4>However, we also like to check that the 16 c=
ompass 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.</FONT>=20
<P><FONT face=3DArial size=3D4>So, what I would like to do is to create the=
se sectors visually, by drawing a line from the origin (an arbitrary "cente=
r" 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 vi=
sually defined.</FONT>=20
<P><FONT face=3DArial size=3D4>Any suggestions as how this can be done (eas=
ily)? Previously, when doing this in AutoCad, I used a radial copy co=
mmand. I haven't noticed a similar command in ArcGIS.</FONT>=20
<P><FONT face=3DArial size=3D4>Finally, once the sampling location is selec=
ted (and the lat/long of that location determined), we need to be able to d=
etermine 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 sa=
mpling 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?</FONT>=20
<P><FONT face=3DArial size=3D4>Finally, food for thought -- How does the pr=
ojection being used effect the accuracy of all of this? Normally we u=
se Albers (equal area) or Mercator (which gives the most accurate rhumb lin=
es), but is there a better projection to use to obtain accurate distances &=
amp; azimuths? I understand from the reading I've done that these fun=
ctions may be rather projection-sensitive.</FONT>=20
<P><FONT face=3D"Monotype Corsiva" size=3D5><B>-- John</B></FONT><FONT face=
=3D"Times New Roman" size=3D3> </FONT>
<P><FONT face=3DArial size=3D4>*Sometimes if there is a prevailing wind bia=
s, we'll bias our sampling locations to that prevailing wind direction, but=
in the current case there is no strong prevailing wind direction - the ann=
ual wind rose shows an almost random 360=B0pattern.</FONT>=20
<P></P></DIV></BODY><PRE>
Cynthia Brown</PRE>