Re: how can i use envi in batch mode to build mask from EVFs [message #52706 is a reply to message #52705] |
Mon, 26 February 2007 16:56   |
stin.wang
Messages: 15 Registered: April 2006
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Junior Member |
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On Feb 27, 12:58 am, "David Streutker" <dstreut...@gmail.com> wrote:
> On Feb 24, 7:59 pm, "stin.wang" <stin.w...@gmail.com> wrote:
>
>> Hello everyone
>
>> i use idl/envi to do some statistic works. first i read landsat tm
>> into envi, calculate ndvi, and so on .
>
>> my question is how can i use envi in batch mode to build mask form
>> EVFs. It's certainly well know in ENVI , open a image and EVFs, click
>> basic tool-mask-build mask. But every month i need do it again
>> according different landsat tm image. It's really boring . I lookup in
>> ENVI library routines for such routine. but i find only
>> ENVI_MASK_APPLY_DOIT , which apply mask to a image. can anybody help
>> me solve this problem?
>
> I've never tried it, but after browsing through the help files, here's
> the direction I would take:
>
> 1. Open and read the EVF file(s) using the functions ENVI_EVF_OPEN,
> ENVI_EVF_READ_RECORD, etc.
> 2. Convert the geographical coordinates to image coordinates using
> ENVI_CONVERT_FILE_COORDINATES.
> 3. Convert the EVF polygons to ROIs using ENVI_CREATE_ROI and
> ENVI_DEFINE_ROI.
> 4. Create a mask image from the ROIs, possibly using
> ENVI_ROI_TO_IMAGE_DOIT.
> 5. Mask your image using ENVI_MASK_APPLY_DOIT.
>
> Hope that helps, and good luck.
>
> -David
I found some words about Envi_roi to image_doit , it's means that this
routine is used to create a classification image from ROIs. Each input
ROI represents a class in the output image. i don't know whether it
can do what i what.
i'll try it ,thank you.
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