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NV5 Geospatial Blog

Each month, NV5 Geospatial posts new blog content across a variety of categories. Browse our latest posts below to learn about important geospatial information or use the search bar to find a specific topic or author. Stay informed of the latest blog posts, events, and technologies by joining our email list!



Not All Supernovae Are Created Equal: Rethinking the Universe’s Measuring Tools

Not All Supernovae Are Created Equal: Rethinking the Universe’s Measuring Tools

6/3/2025

Rethinking the Reliability of Type 1a Supernovae   How do astronomers measure the universe? It all starts with distance. From gauging the size of a galaxy to calculating how fast the universe is expanding, measuring cosmic distances is essential to understanding everything in the sky. For nearby stars, astronomers use... Read More >

Using LLMs To Research Remote Sensing Software: Helpful, but Incomplete

Using LLMs To Research Remote Sensing Software: Helpful, but Incomplete

5/26/2025

Whether you’re new to remote sensing or a seasoned expert, there is no doubt that large language models (LLMs) like OpenAI’s ChatGPT or Google’s Gemini can be incredibly useful in many aspects of research. From exploring the electromagnetic spectrum to creating object detection models using the latest deep learning... Read More >

From Image to Insight: How GEOINT Automation Is Changing the Speed of Decision-Making

From Image to Insight: How GEOINT Automation Is Changing the Speed of Decision-Making

4/28/2025

When every second counts, the ability to process geospatial data rapidly and accurately isn’t just helpful, it’s critical. Geospatial Intelligence (GEOINT) has always played a pivotal role in defense, security, and disaster response. But in high-tempo operations, traditional workflows are no longer fast enough. Analysts are... Read More >

Thermal Infrared Echoes: Illuminating the Last Gasp of a Dying Star

Thermal Infrared Echoes: Illuminating the Last Gasp of a Dying Star

4/24/2025

This blog was written by Eli Dwek, Emeritus, NASA Goddard Space Flight Center, Greenbelt, MD and Research Fellow, Center for Astrophysics, Harvard & Smithsonian, Cambridge, MA. It is the fifth blog in a series showcasing our IDL® Fellows program which supports passionate retired IDL users who may need support to continue their work... Read More >

A New Era of Hyperspectral Imaging with ENVI® and Wyvern’s Open Data Program

A New Era of Hyperspectral Imaging with ENVI® and Wyvern’s Open Data Program

2/25/2025

This blog was written in collaboration with Adam O’Connor from Wyvern.   As hyperspectral imaging (HSI) continues to grow in importance, access to high-quality satellite data is key to unlocking new insights in environmental monitoring, agriculture, forestry, mining, security, energy infrastructure management, and more.... Read More >

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2.8

Batch Processing using an ENVITask

Anonym

Last week, Brian Griglak outlined how to subset an ENVIRaster for use with an ENVITask on IDL Data Point. This functionality is used frequently, but what if you need to go the other direction? What if you need to process multiple files in a single script?

By running a batch process in the ENVI API, you can run a single process (or a chain of processes for that matter) on a list of files, and output the results to a location of your choosing.

An ENVI batch script using ENVITasks must contain 5 elements to run properly:

  • Start the ENVI application, preferably in HEADLESS mode since the UI is not needed.
  • Initialize the ENVITask and set constant parameters.
  • Generate a list of input files to do processing on.
  • Create an output filename - one for each input file.
  • Run the processing over each file in a loop with the parameters of your choice.

 

A lot of the work in creating a batch script does not stem from doing processing, but rather from managing input and output files. The code below outlines how this minimum framework can be setup using the RadiometricCalibration task.

 

pro batch_radiometric_calib

 compile_opt idl2

 

 ;Start ENVI in headless mode

 e = envi(/headless)

 

 ;Instantiate the ENVITask, set constant parameters.

 task = ENVITask('Radiometric')

 task.CALIBRATION_TYPE = 1

 

 ;Find all the files with .dat extensions in a directory.

 search_dir = 'Directory of files to calibrate'

 filelist = file_search(search_dir + '*.dat')

 ;Set a base for your output files that will be appended to.

 outbase = 'C:\Scratch\Reflectance_Cal_'

 

 ;Loop over every file.

 ;Open the raster, set parameters, and execute the task.

 foreach file, filelist, index do begin

   raster = e.OpenRaster(file)

   task.input_raster = raster

   task.output_raster_uri = outbase + strtrim(index, 2)

   task.Execute

 endforeach

end

 

One cool thing about using an ENVITask for batch processing is that each time through the loop, you only have to change the parameters that... well.. change!

 

In the example above, the CALIBRATION_TYPE is set to 1 (to calibrate to top of atmosphere reflectance) outside the loop so it is only set one time. The input_raster and output_raster are set inside the loop - they will change for each file.

At the end of the loop, with the new parameters in place, task.Execute is called. This kicks off processing of the ENVITask with the current parameters, but leaves the task unchanged for subsequent use.

 

To access the current list of ENVITasks:

IDL> e=envi()

ENVI> e.TASK_NAMES

 

For help on functions used in the example:

STRTRIM, FILE_SEARCH, OPENRASTER, COMPILE_OPT
 

 

Happy batching!

1 comments on article "Batch Processing using an ENVITask"

Avatar image

Ivan Alvarez

I have this problem when I try to make a batch proccess

ERROR: Insufficient keyword directives

My code is this

; Add the extension to the toolbox. Called automatically on ENVI startup.

pro test2_extensions_init

; Set compile options

compile_opt IDL2

; Get ENVI session

e = ENVI(/CURRENT)

; Add the extension to a subfolder

e.AddExtension, 'test2', 'test2', PATH=''

end

; ENVI Extension code. Called when the toolbox item is chosen.

pro test2

; Set compile options

compile_opt IDL2

; General error handler

CATCH, err

if (err ne 0) then begin

CATCH, /CANCEL

if OBJ_VALID(e) then $

e.ReportError, 'ERROR: ' + !error_state.msg

MESSAGE, /RESET

return

endif

;Get ENVI session

e = ENVI(/CURRENT)

;******************************************

; Insert your ENVI Extension code here...

;******************************************

;Start ENVI in headless mode

e = envi(/headless)

;Instantiate the ENVITask, set constant parameters.

task = ENVITask('RadiometricCalibration')

task.CALIBRATION_TYPE = 'Radiance'

;Find all the files with .dat extensions in a directory.

CD = 'C:'

search_dir = '../test'

filelist = file_search(search_dir + '*.txt')

;Set a base for your output files that will be appended to.

outbase = 'C:\Scratch\Reflectance_Cal_'

;Loop over every file.

;Open the raster, set parameters, and execute the task.

foreach file, filelist, index do begin

raster = e.OpenRaster(file)

OLIBands = raster[0]

task.input_raster = OLIBands

task.output_raster_uri = outbase + strtrim(index, 2)

task.Execute

endforeach

end

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