# Changing Mercator projection central longitude

**URL:** <https://community.thinkgeo.com/t/changing-mercator-projection-central-longitude/2675>\
**Category:** WinForms\
**Created:** [February 9, 2016, 11:10pm UTC](https://community.thinkgeo.com/t/changing-mercator-projection-central-longitude/2675 "2016-02-09T23:10:41Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Goral](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Goral](https://community.thinkgeo.com/u/Goral)\
**Post date:** [February 9, 2016, 11:10pm UTC](https://community.thinkgeo.com/t/changing-mercator-projection-central-longitude/2675/1 "2016-02-09T23:10:41Z")

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Hi,  
  
  
  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I&nbsp;am&nbsp;applying&nbsp;World&nbsp;Mercator&nbsp;projection.&nbsp;When&nbsp;I&nbsp;tried&nbsp;to&nbsp;change&nbsp;central&nbsp;longitude&nbsp;some&nbsp;portion&nbsp;of&nbsp;map&nbsp;get&nbsp;distorted&nbsp;as&nbsp;shown&nbsp;in&nbsp;image.

 ![](https://community.thinkgeo.com/uploads/default/original/1X/ee3d9d0d507731f818b7eccfd6c86db0b1948c22.png)  
  
  
  
&nbsp;&nbsp;Projection&nbsp;strings:-  
  
&nbsp;&nbsp;&nbsp;proj4.InternalProjectionParametersString&nbsp;=&nbsp;Proj4Projection.GetEpsgParametersString(4326);  
  
&nbsp;&nbsp;&nbsp;proj4.ExternalProjectionParametersString&nbsp;=&nbsp;"+proj=merc&nbsp;+lat\_ts=0&nbsp;+lon\_0=160&nbsp;+k=1.000000&nbsp;+x\_0=0&nbsp;+y\_0=0&nbsp;+ellps=WGS84&nbsp;+datum=WGS84&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;+units=m&nbsp;&nbsp;no\_defs&nbsp;\<\>";  
  
  
  
&nbsp;&nbsp;Please&nbsp;suggest&nbsp;the&nbsp;way&nbsp;to&nbsp;overcome&nbsp;this.  
  
  
  
Thanks,  
  
Goral  
  
  
  
  
  
&nbsp;&nbsp;&nbsp;

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**Author:** ![Ethan](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/ethan/32/19964_2.png) [@Ethan](https://community.thinkgeo.com/u/Ethan)\
**Post date:** [February 10, 2016, 11:48pm UTC](https://community.thinkgeo.com/t/changing-mercator-projection-central-longitude/2675/2 "2016-02-10T23:48:55Z")

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Hi&nbsp;Goral,&nbsp;  
&nbsp;&nbsp;  
&nbsp;Do&nbsp;you&nbsp;make&nbsp;sure&nbsp;your&nbsp;proj4&nbsp;string&nbsp;is&nbsp;correct&nbsp;and&nbsp;suitable&nbsp;its&nbsp;boudingbox?&nbsp;  
&nbsp;&nbsp;  
&nbsp;Please&nbsp;let&nbsp;me&nbsp;know&nbsp;your&nbsp;epsg&nbsp;number&nbsp;so&nbsp;I&nbsp;can&nbsp;have&nbsp;a&nbsp;look&nbsp;into&nbsp;this.&nbsp;  
&nbsp;&nbsp;  
&nbsp;Regards,&nbsp;  
&nbsp;&nbsp;  
&nbsp;Don

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<div class="post-metadata">

**Author:** ![Goral](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Goral](https://community.thinkgeo.com/u/Goral)\
**Post date:** [February 11, 2016, 12:14am UTC](https://community.thinkgeo.com/t/changing-mercator-projection-central-longitude/2675/3 "2016-02-11T00:14:49Z")

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Hi,  
  
  
  
&nbsp;&nbsp;&nbsp;&nbsp;I&nbsp;am&nbsp;using&nbsp;ESRI&nbsp;&nbsp;54004&nbsp;number&nbsp;-&nbsp;World&nbsp;Mercator&nbsp;and&nbsp;trying&nbsp;to&nbsp;change&nbsp;central&nbsp;longitude&nbsp;parameter.&nbsp;Please&nbsp;go&nbsp;through&nbsp;it.  
  
  
  
Thanks,  
  
Goral

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**Author:** ![Peter](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/peter/32/19042_2.png) [@Peter](https://community.thinkgeo.com/u/Peter)\
**Post date:** [February 12, 2016, 6:10am UTC](https://community.thinkgeo.com/t/changing-mercator-projection-central-longitude/2675/4 "2016-02-12T06:10:06Z")

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Hi&nbsp;Goral,&nbsp;  
&nbsp;&nbsp;  
&nbsp;It&nbsp;seems&nbsp;that&nbsp;the&nbsp;issue&nbsp;is&nbsp;caused&nbsp;by&nbsp;the&nbsp;incorrect&nbsp;EPSG&nbsp;parameter,&nbsp;please&nbsp;try&nbsp;the&nbsp;following&nbsp;parameter:&nbsp;  
&nbsp;&nbsp;  
&nbsp;+proj=merc&nbsp;+lat\_ts=0&nbsp;+lon\_0=0&nbsp;+k=1.000000&nbsp;+x\_0=0&nbsp;+y\_0=0&nbsp;+ellps=WGS84&nbsp;+datum=WGS84&nbsp;+units=m&nbsp;no\_defs&nbsp;  
&nbsp;&nbsp;  
&nbsp;Thanks,&nbsp;  
&nbsp;Peter

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**Author:** ![Goral](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/g/4491bb/32.png) [@Goral](https://community.thinkgeo.com/u/Goral)\
**Post date:** [February 14, 2016, 10:32pm UTC](https://community.thinkgeo.com/t/changing-mercator-projection-central-longitude/2675/5 "2016-02-14T22:32:01Z")

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Hi,  
  
  
  
&nbsp;&nbsp;&nbsp;&nbsp;I&nbsp;have&nbsp;+lon\_0&nbsp;parameter&nbsp;purposely.&nbsp;I&nbsp;know&nbsp;because&nbsp;of&nbsp;that&nbsp;only&nbsp;that&nbsp;distortion&nbsp;coming.&nbsp;I&nbsp;want&nbsp;to&nbsp;know&nbsp;if&nbsp;+lon\_0&nbsp;parameter&nbsp;changes&nbsp;then&nbsp;how&nbsp;to&nbsp;avoid&nbsp;that&nbsp;type&nbsp;of&nbsp;distortion.  
  
  
  
Thanks,  
  
Goral

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<div class="post-metadata">

**Author:** ![Peter](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/peter/32/19042_2.png) [@Peter](https://community.thinkgeo.com/u/Peter)\
**Post date:** [February 17, 2016, 12:11am UTC](https://community.thinkgeo.com/t/changing-mercator-projection-central-longitude/2675/6 "2016-02-17T00:11:18Z")

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Hi&nbsp;Goral,&nbsp;  
&nbsp;&nbsp;  
&nbsp;I&nbsp;think&nbsp;some&nbsp;conceptions&nbsp;have&nbsp;been&nbsp;obfuscated.&nbsp;The&nbsp;projection&nbsp;applying&nbsp;scenario&nbsp;is&nbsp;focused&nbsp;on&nbsp;a&nbsp;small&nbsp;distorted&nbsp;region&nbsp;instead&nbsp;of&nbsp;all&nbsp;of&nbsp;the&nbsp;world.&nbsp;If&nbsp;you&nbsp;want&nbsp;to&nbsp;change&nbsp;the&nbsp;region’s&nbsp;position&nbsp;by&nbsp;a&nbsp;customized&nbsp;projection,&nbsp;I&nbsp;think&nbsp;there&nbsp;are&nbsp;some&nbsp;mistakes&nbsp;on&nbsp;some&nbsp;special&nbsp;regions&nbsp;such&nbsp;as&nbsp;the&nbsp;edge&nbsp;of&nbsp;regions.&nbsp;&nbsp;  
&nbsp;&nbsp;  
&nbsp;More&nbsp;information&nbsp;please&nbsp;refer&nbsp;to&nbsp;[gis.stackexchange.com/questions/32115/how-to-determine-projection-parameters-when-customizing-a-projection](http://gis.stackexchange.com/questions/32115/how-to-determine-projection-parameters-when-customizing-a-projection).&nbsp;&nbsp;  
&nbsp;&nbsp;  
&nbsp;Hope&nbsp;it&nbsp;is&nbsp;useful.&nbsp;