| Re: Refine a vector layer in ENVI [message #49136 is a reply to message #49049] |
Fri, 16 June 2006 09:57   |
envi35@yahoo.ca
Messages: 48
Registered: March 2005
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Member |
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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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