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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi, all,<o:p></o:p></p><p class=MsoNormal>I’m trying to track down an issue I’m seeing with Azimuthal Equidistant values when compared to ESRI. The ESRI coordinate system I’m using is World Azimuthal Equidistant. I’m using some sample data that is in the Tucson AZ area.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The coordinate strings we’re passing into PROJ to set up the transform are:<o:p></o:p></p><p class=MsoNormal>Src: +proj=aeqd +lat_0=0 +lon_0=0 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs<o:p></o:p></p><p class=MsoNormal>Dest: +proj=longlat +datum=WGS84 +no_defs<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I pass in the following coordinates (Easting,Northing):<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]> -9939304, 6673447<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>-9930938, 6684888<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I get this result:<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l3 level1 lfo2'><![if !supportLists]><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]> -69d 0’ 0.12”, 32d 15’ 14.159”<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l3 level1 lfo2'><![if !supportLists]><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>-68d 59’ 24.215”, 32d 19’ 5.934”<o:p></o:p></p><p class=MsoNormal>Needless to say, this isn’t anywhere near Tucson, and is about 31-32 degrees off longitudinally.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>When I try using a sphere (I’ve tried both semi major axis and equal-area), the values are much closer, but still off. <o:p></o:p></p><p class=MsoNormal>Src: +proj=aeqd +lat_0=0 +lon_0=0 +x_0=0 +y_0=0 +a=6378137.0 +b=6378137.0 +units=m +no_defs<o:p></o:p></p><p class=MsoNormal>Dest: +proj=longlat +a=6378137.0 +b=6378137.0 +no_defs<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l2 level1 lfo3'><![if !supportLists]><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]> -110d 50’ 50.416”, 32d 6’ 24.361”<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l2 level1 lfo3'><![if !supportLists]><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>-110d 51’ 24.032”, 32d 10’ 15.985”<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Src: +proj=aeqd +lat_0=0 +lon_0=0 +x_0=0 +y_0=0 +a=6371007.1809 +b=6371007.1809 +units=m +no_defs<o:p></o:p></p><p class=MsoNormal>Dest: +proj=longlat +a=6371007.1809 +b=6371007.1809 +no_defs<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo4'><![if !supportLists]><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]> -110d 59’ 11.622”, 32d 4’ 58.135”<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo4'><![if !supportLists]><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>-110d 59’ 45.523”, 32d’ 8’ 49.575”<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Does anyone out there have any idea why this is happening? I’m at my wits end to explain it.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Joe White<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>