Re: Ilwis Digest, Vol 93, Issue 6

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Re: Ilwis Digest, Vol 93, Issue 6

Sahleselassie Amare
Banned User
Dear all,
I am working on a study area which covers THREE (3) UTM zones for Ethiopia. A large area of the country falls under zone 37, but there is still a significant area of it under zones 36 and 38. We use Zone 37N when we do the projections for Ethiopia. But what about for those areas in zones 36 and 38?

My question is, how can we do a correct projection for each THREE zones while we still work on the entire map of Ethiopia without creating three separate maps? GPS readings indicated negative values when I used ONE zone alone (zone 37N) for the entire map. But readings should show zone specific values. How can I do that? Please help if you have any ideas.
(Remember, I wanted to use the UTM, not Decimal Degrees,etc).

Thank you!
SSA.



On Tuesday, October 27, 2015 3:00 PM, "[hidden email]" <[hidden email]> wrote:


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  1. help (water)
  2. Re: help ([hidden email])


----------------------------------------------------------------------

Message: 1
Date: Mon, 26 Oct 2015 10:51:47 +0200
From: water <[hidden email]>
To: <[hidden email]>
Subject: [Ilwis] help
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=UTF-8; format=flowed

Dear friends,

I am using ILWIS 3.3 and 3.8.5 with Windows 7 operating System. When I
import Arcview Shapefiles (projection ? UTM, WGS 84, Zone 36N) to ILWIS
(at 3.3 through Import-> Map or Import->GDAL->ArcView Shape; at 3.8.5
through Import-> GDAL->Vector->ArcView Shape) in the result I have 5
files  (*.dom, *.mpa, *.mpap#, *.mpat#, *.mpz#) and projection ?
UNKNOWN.
Why ILWIS lost the projection?
How to change UNKNOWN to UTM or how to aviod projection losing?

Thank you,
          Victor



------------------------------

Message: 2
Date: Tue, 27 Oct 2015 06:48:48 +0000
From: <[hidden email]>
To: <[hidden email]>
Subject: Re: [Ilwis] help
Message-ID: <[hidden email]>
Content-Type: text/plain; charset="utf-8"

I can only speak for Ilwis 3.8.5. It depends a bit on what the underlying library (gdal) returns. ArcGis and Gdal are not 100% compatible with wkt strings they use for defining coordinate systems. Its unfortunate  (and who knows, it might be an interpretation error on our side of what strings gdal returns). Fortunately you can easily create a new utm system with right zone if you go to the file menu, use the create coordinate system, choose the right projection (utm) and zone and attach that to your map via the property form ( 1 minute work).

Martin Schouwenburg
[hidden email]


-----Original Message-----
From: Ilwis [mailto:[hidden email]] On Behalf Of water
Sent: maandag 26 oktober 2015 9:52
To: [hidden email]
Subject: [Ilwis] help

Dear friends,

I am using ILWIS 3.3 and 3.8.5 with Windows 7 operating System. When I import Arcview Shapefiles (projection ? UTM, WGS 84, Zone 36N) to ILWIS (at 3.3 through Import-> Map or Import->GDAL->ArcView Shape; at 3.8.5 through Import-> GDAL->Vector->ArcView Shape) in the result I have 5 files  (*.dom, *.mpa, *.mpap#, *.mpat#, *.mpz#) and projection ? UNKNOWN.
Why ILWIS lost the projection?
How to change UNKNOWN to UTM or how to aviod projection losing?

Thank you,
          Victor

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------------------------------

End of Ilwis Digest, Vol 93, Issue 6
************************************



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Re: Ilwis Digest, Vol 93, Issue 6

schouwenburg

Nope, not using UTM at least. You will get distortions if you move away from the zone. You can of course use another projection (latlon is not a projection) that is more suitable for the whole of Ethiopia. As Ethiopia is close (enough) to equator a simple Mercator would already work fine but maybe another is better suited.

 

Martin Schouwenburg

[hidden email]

 

From: Ilwis [mailto:[hidden email]] On Behalf Of Sahleselassie Amare
Sent: woensdag 28 oktober 2015 13:52
To: [hidden email]
Subject: Re: [Ilwis] Ilwis Digest, Vol 93, Issue 6

 

Dear all,

I am working on a study area which covers THREE (3) UTM zones for Ethiopia. A large area of the country falls under zone 37, but there is still a significant area of it under zones 36 and 38. We use Zone 37N when we do the projections for Ethiopia. But what about for those areas in zones 36 and 38?

 

My question is, how can we do a correct projection for each THREE zones while we still work on the entire map of Ethiopia without creating three separate maps? GPS readings indicated negative values when I used ONE zone alone (zone 37N) for the entire map. But readings should show zone specific values. How can I do that? Please help if you have any ideas.

(Remember, I wanted to use the UTM, not Decimal Degrees,etc).

 

Thank you!

SSA.

 

 

On Tuesday, October 27, 2015 3:00 PM, "[hidden email]" <[hidden email]> wrote:

 

Send Ilwis mailing list submissions to
    [hidden email]

To subscribe or unsubscribe via the World Wide Web, visit
    http://list.52north.org/mailman/listinfo/ilwis
or, via email, send a message with subject or body 'help' to
    [hidden email]

You can reach the person managing the list at
    [hidden email]

When replying, please edit your Subject line so it is more specific
than "Re: Contents of Ilwis digest..."


Today's Topics:

  1. help (water)
  2. Re: help ([hidden email])


----------------------------------------------------------------------

Message: 1
Date: Mon, 26 Oct 2015 10:51:47 +0200
From: water <[hidden email]>
To: <[hidden email]>
Subject: [Ilwis] help
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=UTF-8; format=flowed

Dear friends,

I am using ILWIS 3.3 and 3.8.5 with Windows 7 operating System. When I
import Arcview Shapefiles (projection ? UTM, WGS 84, Zone 36N) to ILWIS
(at 3.3 through Import-> Map or Import->GDAL->ArcView Shape; at 3.8.5
through Import-> GDAL->Vector->ArcView Shape) in the result I have 5
files  (*.dom, *.mpa, *.mpap#, *.mpat#, *.mpz#) and projection ?
UNKNOWN.
Why ILWIS lost the projection?
How to change UNKNOWN to UTM or how to aviod projection losing?

Thank you,
          Victor



------------------------------

Message: 2
Date: Tue, 27 Oct 2015 06:48:48 +0000
From: <[hidden email]>
To: <[hidden email]>
Subject: Re: [Ilwis] help
Message-ID: <[hidden email]>
Content-Type: text/plain; charset="utf-8"

I can only speak for Ilwis 3.8.5. It depends a bit on what the underlying library (gdal) returns. ArcGis and Gdal are not 100% compatible with wkt strings they use for defining coordinate systems. Its unfortunate  (and who knows, it might be an interpretation error on our side of what strings gdal returns). Fortunately you can easily create a new utm system with right zone if you go to the file menu, use the create coordinate system, choose the right projection (utm) and zone and attach that to your map via the property form ( 1 minute work).

Martin Schouwenburg
[hidden email]


-----Original Message-----
From: Ilwis [mailto:[hidden email]] On Behalf Of water
Sent: maandag 26 oktober 2015 9:52
To: [hidden email]
Subject: [Ilwis] help

Dear friends,

I am using ILWIS 3.3 and 3.8.5 with Windows 7 operating System. When I import Arcview Shapefiles (projection ? UTM, WGS 84, Zone 36N) to ILWIS (at 3.3 through Import-> Map or Import->GDAL->ArcView Shape; at 3.8.5 through Import-> GDAL->Vector->ArcView Shape) in the result I have 5 files  (*.dom, *.mpa, *.mpap#, *.mpat#, *.mpz#) and projection ? UNKNOWN.
Why ILWIS lost the projection?
How to change UNKNOWN to UTM or how to aviod projection losing?

Thank you,
          Victor

_______________________________________________
Ilwis mailing list
[hidden email]
http://list.52north.org/mailman/listinfo/ilwis
http://ilwis.forum.52north.org
Please respect our mailing list guidelines:
http://52north.org/resources/mailing-lists-and-forums/guidelines

------------------------------

Subject: Digest Footer

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------------------------------

End of Ilwis Digest, Vol 93, Issue 6
************************************


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