ENVI EX | Classification Workflow

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Geospatial imagery is more than just a pretty picture or a backdrop to a map. Today, it is used to provide specific information about a geographic area of interest and can help you make decisions that are important in your line of work.

ENVI EX is the newest addition to the ENVI line of premier image processing and analysis software products. It provides user-friendly tools to read, explore, prepare, analyze, and share information extracted from all types of imagery. Designed specifi cally for GIS users and fully integrated with ESRI’s ArcGIS® software, ENVI EX includes unique step-by-step workfl ows that walk you through previously complex image analysis tasks.

What is Classification? Geospatial image classification – a process that groups image pixels into categories for identification and analysis – is an essential task for many image analysts and GIS professionals. Classifying images can provide important information about the type of land cover in an area, such as how much is covered with concrete and how much is grass. Images that have been classified are commonly used for land cover mapping, agricultural assessments, and resource management.

Classification in ENVI EX

The classifi cation workfl ow in ENVI EX allows you to use either of the customary methods of classifying imagery: supervised or unsupervised. Depending on which method you use, you can either pre-identify the types of materials you’re looking for in the image prior to classifi cation or allow ENVI EX to determine the disparate classes in the image for later identifi cation.

Other methods of classifying pixel groups are complex and time consuming and can lead to misidentifi cation and other inadvertent errors. Now, the automated workfl ow in ENVI EX will guide you through each step of the process with intuitive dialog boxes and parameters that are preset based on typical desired outcomes.

The ENVI EX classifi cation workfl ow simplifi es the process of identifying features within imagery. And, ENVI EX is fl exible so you can modify parameters and data at any stage of the process, allowing you to get the specifi c information you need from your imagery and make more informed decisions.

Select the Image You Want to Classify Select an image from web or local search results, from ArcGIS, or from Windows® Explorer and simply drag and drop it into ENVI EX. ENVI EX supports imagery from today’s most popular satellite and airborne sensors, and it can classify files in over 70 types and formats.   Choose a Classification Method The ENVI EX workflow allows you to choose either a supervised or unsupervised classification method. The classification method can be easily chosen based on whether you have knowledge about, or wish to provide input into, the classification process.

Supervised Classification Choose supervised classifi cation when you want to pre-identify information related to an image. This method allows you to cluster pixels and pre-define classes, creating “training data” for ENVI EX to work from when classifying the rest of the image. The training data can be defined on-the-fl y, loaded from a geodatabase, or opened from a ground control points file. Unsupervised Classification Choose unsupervised classifi cation when you do not have any pre-existing knowledge or do not wish to pre-identify classes in an image. In unsupervised classification, ENVI EX uses an automated technique to search for regions or classes. At any point during unsupervised classification, ENVI EX will allow you to make adjustments to the grouping of the imagery.

Cleanup of the Data

During the optional clean-up step of the classification workflow, you can choose to apply smoothing and aggregation tools to make features more true-to-life and refine your results. At any time, you can also check the ENVI EX preview portal window to view your preliminary classification results. This gives you the ability to modify results on-the-fly by changing input data.

View, Export, and Use Results Export the classification results as an image or export specific classes as layers. Results can be printed, included as part of a PowerPoint presentation, or saved to your computer, a geodatabase, or directly into an ArcGIS file. Additional analysis can also be done within ENVI EX or ArcGIS.

Unlock the information in your imagery. From reading and preparing, to exploring, analyzing, and sharing – you’ll get information from imagery quickly and easily with the automated ENVI EX workflows.

To learn more about ENVI EX contact your ENVI representative.