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Question

Clip Imagery based on polygon


checcosisani
Contributor
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Hi all

I created a bounding box polygon and I want to use to clip and export raster imagery reading the imagery from my server

Is it correct to use wms reader to read imagery and then ? clipper ?

How can setup the resolution of my clipped output ?

thx

Francesco

10 replies

david_r
Evangelist
  • June 28, 2018

The clipped output will have the same resolution as the intput, i.e. the image returned by the WMS server. You can tweak the WMS parameters (the combination of the bounding box and image size) to manipulate the WMS image scale.

You can also use the RasterResampler, but it works best if the difference between the input and the desired output isn't too big.


checcosisani
Contributor
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  • Author
  • Contributor
  • June 28, 2018
david_r wrote:

The clipped output will have the same resolution as the intput, i.e. the image returned by the WMS server. You can tweak the WMS parameters (the combination of the bounding box and image size) to manipulate the WMS image scale.

You can also use the RasterResampler, but it works best if the difference between the input and the desired output isn't too big.

Hi David

 

 

thx for quick answer .... but I don't understand why I'm not able to clip the imagery on wms server ..maybe there is some step that I miss ?

 

 

do you have any suggestion ?

 

 

thx

 

 

Francesco

 

 

 


david_r
Evangelist
  • June 28, 2018
checcosisani wrote:
Hi David

 

 

thx for quick answer .... but I don't understand why I'm not able to clip the imagery on wms server ..maybe there is some step that I miss ?

 

 

do you have any suggestion ?

 

 

thx

 

 

Francesco

 

 

 

Impossible to say without more information. Can you post some screenshots and some log entries?

checcosisani
Contributor
Forum|alt.badge.img+12
  • Author
  • Contributor
  • June 28, 2018

Yes maybe I have to zoom in into the area to clip using the search envelope but I can read the min xy max xy from external data


checcosisani
Contributor
Forum|alt.badge.img+12
  • Author
  • Contributor
  • June 28, 2018
david_r wrote:
Impossible to say without more information. Can you post some screenshots and some log entries?

below a screenshot

 

 


david_r
Evangelist
  • June 28, 2018
checcosisani wrote:

below a screenshot

 

 

You can convert those attributes to a polygon feature using the 2DBoxReplacer and send it into a FeatureReader configured for your WMS. The polygon will be used as the search envelope. You can configure the image size inside the WMS reader parameters, together with the bounding box it will define the scale of the returned image.

checcosisani
Contributor
Forum|alt.badge.img+12
  • Author
  • Contributor
  • June 28, 2018
david_r wrote:
You can convert those attributes to a polygon feature using the 2DBoxReplacer and send it into a FeatureReader configured for your WMS. The polygon will be used as the search envelope. You can configure the image size inside the WMS reader parameters, together with the bounding box it will define the scale of the returned image.
Hi David

 

 

thx for support step by step I'm approaching the result but.....

 

 

now I would like to export one clipped image for every polygon (I created an Id unique for each polygon) used to clip

 

 

I have to use fanout with POlygon-ID

 

 

thx

 

 

Francesco

 

 


david_r
Evangelist
  • June 28, 2018
checcosisani wrote:
Hi David

 

 

thx for support step by step I'm approaching the result but.....

 

 

now I would like to export one clipped image for every polygon (I created an Id unique for each polygon) used to clip

 

 

I have to use fanout with POlygon-ID

 

 

thx

 

 

Francesco

 

 

I'm not sure I understand. What happens when you run the current workspace? Do you get any error messages?

checcosisani
Contributor
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  • Author
  • Contributor
  • June 28, 2018
david_r wrote:
I'm not sure I understand. What happens when you run the current workspace? Do you get any error messages?
No error

 

I just want to export one single image per every polygon because at the moment my output is composed by only one image

 

 


Forum|alt.badge.img+2
checcosisani wrote:
No error

 

I just want to export one single image per every polygon because at the moment my output is composed by only one image

 

 

What about using the FeatureReader for your WMS read. Then you can pass in the search envelope values to the reader.

 

 


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