| Re: Refine a vector layer in ENVI [message #49369 is a reply to message #49183] |
Tue, 18 July 2006 10:06   |
envi35@yahoo.ca
Messages: 48
Registered: March 2005
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Member |
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Hi Chris,
Thanks! Hope there will be more vector functions in the next version of
ENVI!
Jenny
cpadwick@ittvis.com wrote:
> Hi Jenny,
>
> ENVI lets you move newly added vectors as a whole, but not ones you are
> editing...the assumption being that your vector layers may be off as a
> whole and that might be better handled with a warp operation instead.
>
> hope that helps,
>
> Chris
>
> Jenny wrote:
>> Hi Chris, you are absolutely right about the projections! The Landsat
>> image was in UTM, and the shapefiles in Stereographic. I just
>> reprojected the Landsat TM to Stereographic too, and it works fine now!
>>
>>
>> May I ask you more question: Is there a way to reduce the number of
>> nodes of a vector all at once? there are many nodes assocated with my
>> vector, it takes a while to adjust only a apart of it. I don't care too
>> much about the final accuracy of my vector layer as long as it shows
>> the right outline of the lakes.
>>
>> It would be great if ITT could add more functions to the Vector
>> Paranmeter dialog in the next version of ENVI. Such as to shift the
>> whole vector layer a bit.
>>
>> Many thanks,
>> Jenny
>>
>>
>>
>> cpadwick@ittvis.com wrote:
>>> I'm wondering if it's something specific to either the shapefile or the
>>> Landsat image. Can you find out the projection info for both files you
>>> are using?
>>>
>>> Chris
>>>
>>> Jenny wrote:
>>>> Hi Chris,
>>>>
>>>> Thanks for your reply. I'm using ENVI 4.2 too. I just repeated what you
>>>> tried and the vector is fine like you said, the nodes didn't move. I'm
>>>> wondering if it has something to do with my old shapefiles. I'll try
>>>> more and keep you posted.
>>>>
>>>> Regards,
>>>> Jenny
>>>>
>>>> cpadwick@ittvis.com wrote:
>>>> > Hi Jenny,
>>>> >
>>>> > I just tried a test with ENVI 4.2 and was not able to repeat the
>>>> > behavior you described. Here's what I tried:
>>>> >
>>>> > -open bhtmref.img in the default data directory
>>>> > -display it
>>>> > -click Overlay->Vectors. Vector parameters comes up
>>>> > -click File->Create New Layer. Choose layer name and output file,
>>>> > click ok.
>>>> > -Available Vectors List comes up. Load the new layer into the display.
>>>> > -in the Vector Parameters Dialog, click Mode->Add New Vectors
>>>> > -draw some polygons on the screen and save them
>>>> > -Click Mode->Edit Existing Vectors
>>>> > -select a vector and move its nodes around. When finished right
>>>> > click->Accept Changes
>>>> >
>>>> > The nodes stay where I placed them, and I don't notice any movement
>>>> > like you described. What version of ENVI are you working with?
>>>> >
>>>> > Chris
>>>> >
>>>> >
>>>> >
>>>> >
>>>> > Jenny wrote:
>>>> > > I've come across the following problems several times, and I'm
>>>> > > wondering if somebody know a way to fix it. I have shapefiles of lakes
>>>> > > in a region, which was produced about 40 years ago. When I overlay the
>>>> > > lake shapefiles to a recent Landsat image, the shapefiles do not
>>>> > > outline the lakes exactly for the area of the lakes have changed over
>>>> > > the years. So I want to edit the vector layer to make it fit the
>>>> > > outline of the lakes in my Landsat image. This doesn't seem to be
>>>> > > difficult using the Vector Parameters dialog in ENVI (Mode/Edit
>>>> > > existing vectors). However, when I drag the nodes to move them in the
>>>> > > desired location in the right side of the vector layer, the whole
>>>> > > vector (or the left side of it) moves too! When I fixed all the
>>>> > > problems in the right side and saved it to the layer, and start
>>>> > > editting the left side, the right side of the vector layer moves again
>>>> > > with each editting. Thus I can never make it fix a whole lake.
>>>> > >
>>>> > > Does anybody have similar experience? Or is this a bug?
>>>> > >
>>>> > > Thanks,
>>>> > > Jenny
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