| Re: Refine a vector layer in ENVI [message #49183 is a reply to message #49136] |
Tue, 27 June 2006 13:38   |
cpadwick
Messages: 4
Registered: June 2006
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Junior Member |
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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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