wg84 projection problem

[Markus Nater]

Some javascript/style in this post has been disabled (why?)

Hi List

I have some polygons in qgis with wgs84 projection. But when I try to measure distance in meters, it gives me back 1cm for 0.1 degrees, which is of course totally wrong.
how can I fix this, so I will have the correct measurements in meters?

cheers
markus

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Otto Dassau]

Hi Markus,

On Thu, 29 Oct 2009 14:32:16 +0700
Markus Nater <[hidden email]> wrote:

> Hi List
>
> I have some polygons in qgis with wgs84 projection. But when I try to
> measure distance in meters, it gives me back 1cm for 0.1 degrees, which
> is of course totally wrong.
> how can I fix this, so I will have the correct measurements in meters?

you have to define:

a) settings => project properties => general => layer units (select meters)
b) settings => options => map tools => ellipsoid for distance calculation

to fit the ellipsoid used in your CRS.

> cheers
> markus

Regards,
 Otto
_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Alex Mandel-2]

Markus Nater wrote:

> Hi List
>
> I have some polygons in qgis with wgs84 projection. But when I try to
> measure distance in meters, it gives me back 1cm for 0.1 degrees, which
> is of course totally wrong.
> how can I fix this, so I will have the correct measurements in meters?
>
> cheers
> markus
>

Enable projection on the fly, and pick a projected coordinate system.
Technically in WGS84 the best you could get is great circle distances,
and I'm not sure the measure tool does this yet. So you need to be in a
projection that flattens the map evenly for distance measurement.

Alex

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Werner Macho]

hi all

regarding setting b)
why is there a double entry of WGS84 in the Ellipsoid for distance
calculation? One at the top and one at the bottom ..
bug? feature?

greetings
Werner
> you have to define:
>
> a) settings => project properties => general => layer units (select meters)
> b) settings => options => map tools => ellipsoid for distance calculation
>
> to fit the ellipsoid used in your CRS.
>
>  

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Otto Dassau]

On Thu, 29 Oct 2009 09:37:18 +0100
Werner Macho <[hidden email]> wrote:

> hi all
>
> regarding setting b)
> why is there a double entry of WGS84 in the Ellipsoid for distance
> calculation? One at the top and one at the bottom ..

my svn version from last week does include WGS 60, WGS 66, WGS 72, WGS 84 -
but none of them is duplicated. -> ?

> bug? feature?
>
> greetings
> Werner
> > you have to define:
> >
> > a) settings => project properties => general => layer units (select
> >    meters)
> > b) settings => options => map tools => ellipsoid for distance calculation

> >
> > to fit the ellipsoid used in your CRS.
> >
> >  
_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Flavio Rigolon]

2009/10/29 Werner Macho <[hidden email]>

hi all

regarding setting b)
why is there a double entry of WGS84 in the Ellipsoid for distance calculation? One at the top and one at the bottom ..
bug? feature?

I confirm: in my 1.3 mimas (on Debian) WGS84 is duplicated. One on the top adn another one on the bottom of the list

greetings
flavio

--
Linux, perche' no? Io uso debian.

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Werner Macho]

sorry - forgot to write .. daphnis on windows - so it seems i'm pretty
out of date here @work ..
my fault .. sorry sorry sorry ..
didn't take a look at the start screen ..
to busy ;)

regards
Werner

> On Thu, 29 Oct 2009 09:37:18 +0100
> Werner Macho <[hidden email]> wrote:
>
>  
>> hi all
>>
>> regarding setting b)
>> why is there a double entry of WGS84 in the Ellipsoid for distance
>> calculation? One at the top and one at the bottom ..
>>    
>
> my svn version from last week does include WGS 60, WGS 66, WGS 72, WGS 84 -
> but none of them is duplicated. -> ?
>
>  
>> bug? feature?
>>
>> greetings
>> Werner
>>    
>>> you have to define:
>>>
>>> a) settings => project properties => general => layer units (select
>>>    meters)
>>> b) settings => options => map tools => ellipsoid for distance calculation
>>>      
>
>  
>>> to fit the ellipsoid used in your CRS.
>>>
>>>  
>>>      

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Markus Nater]

Some javascript/style in this post has been disabled (why?)

thank you Alex
and thank you Otto

when I do take a projected coord system (set to wgs84 zone 47N), the measurements are correct.
but then arises a new problem, as I have a raster shaded relief as geotiff overlayed, that is referenced in wgs84. projection on the fly makes this raster invisible... strangely! and I havent found out how to work around this yet. i cant work out to reproject this raster either, somehow nothing ever happens using the gdal raster translation.
any ideas how to solve this little problem? :-)

cheers
markus


Alex Mandel schrieb:

Markus Nater wrote:
  

Hi List

I have some polygons in qgis with wgs84 projection. But when I try to
measure distance in meters, it gives me back 1cm for 0.1 degrees, which
is of course totally wrong.
how can I fix this, so I will have the correct measurements in meters?

cheers
markus

    

Enable projection on the fly, and pick a projected coordinate system.
Technically in WGS84 the best you could get is great circle distances,
and I'm not sure the measure tool does this yet. So you need to be in a
projection that flattens the map evenly for distance measurement.

Alex

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user
  

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Werner Macho]

Hi!
Installed Mimas on Windows here -> problem confirmed .. two WGS84 to
select at "Settings -> Options -> Map tools -> Ellipsoid for distance
calculations"
One WGS84 directly at the top to select - the other one at the bottom
above Walbeck ellipsoid.

Probably already solved in SVN .. As I don't have a SVN version here I
can only use prepared ..

Thx for confirming Flavio - I'll take a look at SVN-Version as soon as
I'm back home again

regards
Werner

>
> 2009/10/29 Werner Macho <[hidden email]
> <mailto:[hidden email]>>
>
>     hi all
>
>     regarding setting b)
>     why is there a double entry of WGS84 in the Ellipsoid for distance
>     calculation? One at the top and one at the bottom ..
>     bug? feature?
>
>
> I confirm: in my 1.3 mimas (on Debian) WGS84 is duplicated. One on the
> top adn another one on the bottom of the list
>
> greetings
> flavio
>
> --
> Linux, perche' no? Io uso debian.

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Alex Mandel-2]

Were you using GDAL Translate on the command line(if so what was the
command you used?) or with the new GDAL Tools python plugin in QGIS? Did
it give you an error or just fail to show up. I tend to start by
importing the Raster 1st to make sure it's in the projection I want it
in before overlaying Vectors.

Alex

Markus Nater wrote:

> thank you Alex
> and thank you Otto
>
> when I do take a projected coord system (set to wgs84 zone 47N), the
> measurements are correct.
> but then arises a new problem, as I have a raster shaded relief as
> geotiff overlayed, that is referenced in wgs84. projection on the fly
> makes this raster invisible... strangely! and I havent found out how to
> work around this yet. i cant work out to reproject this raster either,
> somehow nothing ever happens using the gdal raster translation.
> any ideas how to solve this little problem? :-)
>
> cheers
> markus
>
>
> Alex Mandel schrieb:
>> Markus Nater wrote:
>>  
>>> Hi List
>>>
>>> I have some polygons in qgis with wgs84 projection. But when I try to
>>> measure distance in meters, it gives me back 1cm for 0.1 degrees, which
>>> is of course totally wrong.
>>> how can I fix this, so I will have the correct measurements in meters?
>>>
>>> cheers
>>> markus
>>>
>>>    
>>
>> Enable projection on the fly, and pick a projected coordinate system.
>> Technically in WGS84 the best you could get is great circle distances,
>> and I'm not sure the measure tool does this yet. So you need to be in a
>> projection that flattens the map evenly for distance measurement.
>>
>> Alex
>>
>> _______________________________________________
>> Qgis-user mailing list
>> [hidden email]
>> http://lists.osgeo.org/mailman/listinfo/qgis-user
>>  
>

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Otto Dassau]

On Thu, 29 Oct 2009 15:54:44 +0700
Markus Nater <[hidden email]> wrote:

> thank you Alex
> and thank you Otto
>
> when I do take a projected coord system (set to wgs84 zone 47N), the
> measurements are correct.
> but then arises a new problem, as I have a raster shaded relief as
> geotiff overlayed, that is referenced in wgs84. projection on the fly
> makes this raster invisible... strangely! and I havent found out how to
> work around this yet. i cant work out to reproject this raster either,
> somehow nothing ever happens using the gdal raster translation.
> any ideas how to solve this little problem? :-)

your data in "wgs84 zone 47N" is probably something like:

CRS: Projected Coordinate System "UTM zone 47N"
Ellipsoid: WGS84

=> EPSG: 32647 ?

and the WGS 84 raster might be:

CRS: Geographic Coordinate System "WGS84"
Ellipsoid: WGS 84

=> EPSG: 4326 ?

that would mean your 2 layers are projected in 2 different CRS.

QGIS supports OTF for vector layers. So you can load a raster, define its
CRS, activate OTF and then load a vector layer projected in another CRS.

Regards,
 Otto

> cheers
> markus
>
>
> Alex Mandel schrieb:
> > Markus Nater wrote:
> >  
> >> Hi List
> >>
> >> I have some polygons in qgis with wgs84 projection. But when I try to
> >> measure distance in meters, it gives me back 1cm for 0.1 degrees, which
> >> is of course totally wrong.
> >> how can I fix this, so I will have the correct measurements in meters?
> >>
> >> cheers
> >> markus
> >>
> >>    
> >
> > Enable projection on the fly, and pick a projected coordinate system.
> > Technically in WGS84 the best you could get is great circle distances,
> > and I'm not sure the measure tool does this yet. So you need to be in a
> > projection that flattens the map evenly for distance measurement.
> >
> > Alex
> >
> > _______________________________________________
> > Qgis-user mailing list
> > [hidden email]
> > http://lists.osgeo.org/mailman/listinfo/qgis-user
> >  

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Markus Nater]

Some javascript/style in this post has been disabled (why?)

I tried it in the python plugin  and yes, it gives me
ERROR 1: Can't load requested DLL: C:\OSGeo4W\apps\gdal-16\bin\gdalplugins\gdal_ECW_JP2ECW.dll 126: Das angegebene Modul wurde nicht gefunden.
which is probably my fault that I have not installed this yet.
thanks a lot for your tip about loading the raster first!
cheers
markus

Alex Mandel schrieb:

Were you using GDAL Translate on the command line(if so what was the
command you used?) or with the new GDAL Tools python plugin in QGIS? Did
it give you an error or just fail to show up. I tend to start by
importing the Raster 1st to make sure it's in the projection I want it
in before overlaying Vectors.

Alex

Markus Nater wrote:
  

thank you Alex
and thank you Otto

when I do take a projected coord system (set to wgs84 zone 47N), the
measurements are correct.
but then arises a new problem, as I have a raster shaded relief as
geotiff overlayed, that is referenced in wgs84. projection on the fly
makes this raster invisible... strangely! and I havent found out how to
work around this yet. i cant work out to reproject this raster either,
somehow nothing ever happens using the gdal raster translation.
any ideas how to solve this little problem? :-)

cheers
markus


Alex Mandel schrieb:
    

Markus Nater wrote:
 
      

Hi List

I have some polygons in qgis with wgs84 projection. But when I try to
measure distance in meters, it gives me back 1cm for 0.1 degrees, which
is of course totally wrong.
how can I fix this, so I will have the correct measurements in meters?

cheers
markus

    
        

Enable projection on the fly, and pick a projected coordinate system.
Technically in WGS84 the best you could get is great circle distances,
and I'm not sure the measure tool does this yet. So you need to be in a
projection that flattens the map evenly for distance measurement.

Alex

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user
  
      

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user
  

_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Barend Kobben]

+1 confirmation, MIMAS 1.3.0 (code rev 11654) on MAC OSX ...

--
Barend Köbben
International Institute for Geo-Information
Sciences and Earth Observation (ITC)
PO Box 6, 7500AA Enschede, The Netherlands
[phone]



On 29-10-09 09:51, "flavio rigolon" <[hidden email]> wrote:

>
>
> 2009/10/29 Werner Macho <[hidden email]>
>> hi all
>>
>> regarding setting b)
>> why is there a double entry of WGS84 in the Ellipsoid for distance
>> calculation? One at the top and one at the bottom ..
>> bug? feature?
>>
>
> I confirm: in my 1.3 mimas (on Debian) WGS84 is duplicated. One on the top adn
> another one on the bottom of the list
>
> greetings
> flavio

International Institute for Geo-Information Science and Earth Observation (ITC)
Chamber of Commerce: 410 27 560

E-mail disclaimer
The information in this e-mail, including any attachments, is intended for the addressee only. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution or action in relation to the content of this information is strictly prohibited. If you have received this e-mail by mistake, please delete the message and any attachment and inform the sender by return e-mail. ITC accepts no liability for any error or omission in the message content or for damage of any kind that may arise as a result of e-mail transmission.
_______________________________________________
Qgis-user mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-user