How do I efficiently find the line and sample image values in an NITF image to perform a spatial subset / chip /clip within ArcGIS for Desktop 10.4 ?

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03-04-2017 12:36 PM
KevinCrichlow1
New Contributor III

CBenkelman-esristaff

Dan_Patterson

NITF Extension for ArcGIS - Performing a Spatial Subset of an Image

PROBLEM 

1. What is the most efficient way to go about setting the size of my spatial subset AOI ?

     I.e . Where in ArcGIS can i get the line and sample values to display so that i can input them into the box to subset it ?

USE CASE STEPS 

1. Draw an extent box with the graphic tool from the Drawing toolbar. 

2. Export that AOI as an NITF subset such that it preserves the RPC info inside the ICHIPB tag.

ISSUE ENCOUNTERED - See accompanying attached .png 

The problem is the interface only allows you to specify your extents in terms of line and sample values.

I tried going to Data Frame > General tab > Units but there is nothing there 

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KevinCrichlow1
New Contributor III

Further to my last, i found the following link: - 

Displaying Images in an Image Coordinate System—Help | ArcGIS for Desktop 

I developed the following Use Case and subsequently Crashed and Burn't.

USE CASE - RECORD Image Coordinates and Perform Spatial Subset of your NITF image using the NITF Add In for ArcGIS Desktop 

ENVIRONMENT

SOFTWARE: ArcGIS 10.4.1 & NITF for ArcGIS 

PHASE 1 - TRANSFORM IMAGERY INTO ICS

1. You can use the Imagery Analysis toolbar > "Focus on Image" to transform the NITF image into its ICS

2. Look in the bottom right hand corner of ArcGIS and you will see the "image coordinates" show up next to the Geo coordinates.

PHASE 2 - DELINEATE YOUR SPATIAL SUBSET EXTENT BOX 

1. Use the graphics tool from the Drawing toolbar to drawn a spatial subset AOI 

2. Place your cursor on the TL & BR of the extent box and record the Column & Row values 

NOTE : - The NITF specification uses the convention (Row, Column), however ESRI uses (Column, Row)

PHASE 3 - PERFORM SPATIAL SUBSET 

1. Go to Image Analysis Toolbar and take off the "Focus to Image" option.

    This will transform the image back into its GCS / PCS

NOTE : You must perform this step otherwise the NITF tool will not be able to perform the spatial subset. 

2. Right click on the image and choose NITF > NITF Save As 

3. Type in your Column and Row values in the Sample & Line boxes. (Take care not to kick the numbers, if your thinking in Line & Sample) 

4. Click Ok

5. Specify location to save your image and click ok

6. Re - add your new spatial subset NITF image to your Data Frame. 

END RESULT 

1. Your spatial subset will be in the wrong spot. - 

QUESTIONS 

Cody Benkelman

Dan Patterson

Simon Woo

SUMMARY 

1. The image chip (spatial subset) is in the wrong place because the NITF Add In requires you to revert back to the Image GCS / PCS

   

    As such, the line and sample values have now changed from those that were recorded when the image was in an  ICS

REQUEST FOR FIX

1. Ask Harris Geospatial to put in an option to allow a user to select a subset in the same manner that ArcGIS for Desktop allows with a graphic / FC / shapefile and Data Frame > Clip Options

OR

2.  The simpler option - Can ESRI create a patch for 10.3.1 and 10.4.1 and 10.5 that will allow the mouse to expose the Line and Sample values of the image while you are roaming around with the image still in its GCS / PCS.

    This would allow the user to use the NITF Add for ArcGIS as is and chip the imagery in the right location. 

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