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ivac2:firdef_map_latlon [2011/11/19 15:12]
filip created
ivac2:firdef_map_latlon [2017/04/08 14:27] (current)
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-[[ivac2:​firdef_toc|Back]] 
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 ====== Latitude and Longitude attributes ====== ====== Latitude and Longitude attributes ======
  
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 When a map is loaded all points defined as a latitude/​longitude pair are transformed to cartesian X/Y values relative to the system origin point and stored as such internally. When a map is loaded all points defined as a latitude/​longitude pair are transformed to cartesian X/Y values relative to the system origin point and stored as such internally.
 So using cartesian X/Y  might slightly improve startup speed but keep in mind that in that case the system origin point cannot be changed. So using cartesian X/Y  might slightly improve startup speed but keep in mind that in that case the system origin point cannot be changed.
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 </p> </p>
 </​HTML>​ </​HTML>​
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 The format of the latitude/​longitude values is **//​Zdddmmsssss//​** where: The format of the latitude/​longitude values is **//​Zdddmmsssss//​** where:
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   * sssss = seconds with maximum 3 decimal places (max 59.999)   * sssss = seconds with maximum 3 decimal places (max 59.999)
  
-The predefined //<​point>//​ elements are defined in the [[ivac2:​firdef_points_xml|points.xml]] file.  Use the id attribute to use a predefined //<​point>//​ element.+The predefined //<​point>//​ elements are defined in the [[ivac2:​firdef_points_xml|points.xml]] file.  Use the **ref** ​attribute to use a predefined //<​point>//​ element. 
 + 
  
 latitude/​longitude example: latitude/​longitude example:
   * lat="​N0543000000"​ → N054:​30:​00.000   * lat="​N0543000000"​ → N054:​30:​00.000
   * lon="​W0033535000"​ → W003:​35:​35.000   * lon="​W0033535000"​ → W003:​35:​35.000
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 The trailing zeroes are not required, the following is also valid: W003:​35:​35.000 → lon="​W0033535" ​ The trailing zeroes are not required, the following is also valid: W003:​35:​35.000 → lon="​W0033535" ​
  
  
-===== Example ​=====+=== Example === 
 +<code XML> 
 +<point lat="​N0504413"​ lon="​E0043108"/>​ 
 +<point lat="​N0504421"​ lon="​E0042601"/>​ 
 +<point lat="​N0504528"​ lon="​E0042119"/>​ 
 +</​code>​ 
 + 
 + 
 + 
 +===== Sectorfile latitude/​longitude overflow bug ===== 
 + 
 + 
 + 
 +Keep a sharp lookout for a major bug in latitude and longitude coordinates which originate from IvAc v1 sectorfiles created with the old //sector file creator website//​. ​ Apparently IVAC v1 did not care about this error and just used the data regardless of the overflow value. 
 + 
 + 
 +You often see coordinates like: 
 + 
 +  W0023260000 -> 002:​32:​60.000 
 + 
 +Notice the overflow value in the seconds part: **60 seconds** ?! 
 + 
 +60 seconds = 1 minute .... The maximum seconds value should be 59.999 seconds - so we have an overflow issue: 
 + 
 +  002:​32:​60.000 should be corrected to 002:​33:​00.000 
 + 
 + 
 +You will also find coordinates like E0082339001 ending in '​1'​. These are also calculation errors and can be safely set to '​0'​ 
 + 
 + ​E0082339001 -> E0082339000 
 + 
 + 
 +==== How to find any occurences of the bug? ==== 
 + 
 +Check the log file for errors in *log/​ivac.log* for an overflow error similar to: 
 + 
 + ERROR Java2D Queue Flusher ... out of range:​E0023260000 
 + 
 +Simply use your text editor to search for the listed coordinate. 
 + 
 + 
 +---- 
 + 
 +[[ivac2:​firdef|Back]] 
 + 
  
-  <point lon="​E0043127"​ lat="​N0511038"/>​ 
-  <point lon="​E0043140"​ lat="​N0511101"/>​ 
-  ​ 
-  <point x="​-0.601415"​ y="​-0.132565"/>​ 
-  <point x="​-0.601393"​ y="​-0.133375"/>​ 
-  ​ 
-  <point ref=”REMBA”/>​ 
-  <point ref=”EBBR-IAF-25L”/>​ 
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