This software release includes the new and enhanced features listed below. See the following sections:

Installer

The IDL and ENVI software installers now use the Inno Setup application. Installation and uninstallation are significantly faster. Instructions for running silent installations are available in the software web download instructions or the DVD installation instructions.

Supported Data Types

ENVI supports the following sensors and data types:

  • Gaofen-2

Image Processing and Display

The Viewshed Analysis workflow and the corresponding API task (ViewshedRaster) were updated with new observer view constraints such as horizontal and vertical field of view, azimuth, and pitch. When combined with range and observer height (which were already in ENVI), these view constraints can more accurately model line-of-sight analyses. The Viewshed Analysis tutorial uses new data files to show different ways to determine visibility from multiple view sources.

ENVI now uses the Izraelevitz (2003) algorithm for viewshed analysis, which is an extension to the original Xdraw algorithm developed by Franklin et al. (1994). The Izraelevitz algorithm performs well in densely sampled terrain elevation models, and it is significantly faster than the radial interpolation method used in previous versions of ENVI.

References:

Franklin, W.R., C.K. Ray, and S. Mehta. Geometric Algorithms for Siting of Air Defense Missile Batteries, Technical Report DAAL03-86-D-0001 (1994), Battelle, Columbus Division, Columbus, OH, 129 p.

Izraelevitz, D. "A Fast Algorithm for Approximate Viewshed Computation." Photogrammetric Engineering & Remote Sensing 69, No. 7 (2003): 767-774.

Use File > Open to open MODIS (HDF-EOS), ASTER (HDF-EOS), and EO-1 ALI and Hyperion (HDF4) files. In previous versions, you had to use the File > Open As > Optical Sensors > sensor type menu option.

ENVI programmers can manually create XML templates for reading data HDF4 and NetCDF-3 datasets, in the Dataset Browser. Previously, templates only worked with HDF5 and NetCDF-4 datasets. Templates are helpful in building the same raster and metadata structure from several scientific data formats. Using a template prevents you from having to use the Dataset Browser to re-define the raster and metadata for every file. See the Open Scientific Data Formats topic in ENVI Help for more information.

The Calculate Cloud Mask Using Fmask tool was redesigned and simplified from the previous version. You no longer have to calibrate the imagery or create a layer stack before adding the imagery to the tool. It automatically calibrates the imagery and determines the appropriate multispectral, thermal, and cirrus bands to use in creating a cloud mask. It currently supports the following sensors:

  • Landsat 4-5 TM
  • Landsat 7 ETM+
  • Landsat 8
  • Sentinel-2 Level-1C
  • NPP VIIRS Moderate Resolution (750 m) reflectance and brightness temperature SDR data downloaded from NOAA CLASS (HDF5 format)

The Normalized Difference Snow Index (NDSI) was updated to use any green band ranging from 0.5 to 0.6 µm and any shortwave-infrared band ranging from 1.55 to 1.75 µm. The NDSI is based on the following references:

Hall, D., G. Riggs, and V. Salomonson. "Development of Methods for Mapping Global Snow Cover Using Moderate Resolution Imaging Spectroradiometer Data." Remote Sensing of Environment 54, No. 2 (1995): 127-140.

Salomonson, V., and I. Appel. "Estimating Fractional Snow Cover from MODIS Using the Normalized Difference Snow Index." Remote Sensing of Environment 89 (2004): 351-360.

The Description and/or the Coordinates string from the Feature Counting Tool table now display in the view.

If any layer in a view has a standard, RPC, or pseudo spatial reference, you can change the base projection of the view to any supported map projection. Right-click on the View layer in the Layer Manager and select Change Base Projection, then use the Select Coordinate System dialog to choose a projection.

The RPC Orthorectification Using Reference Image tool was updated to include a new parameter: Output Pixel Size in the X and Y direction, in meters. The default value is derived from the pixel size of the input image.

If a view contains a standard, RPC, or pseudo projection, you can overlay grid lines in that view by clicking the Grid Lines button in the ENVI toolbar.

Run ENVI Analytics at the Command Line

The envitaskengine executable allows users to run ENVITasks in command-line environments. You can now plug ENVI analytics into applications in different programming languages or environments that share information. The environments must be able to handle standard streams (stdin, stdout, and stderr).

Programming

The following ENVITasks are available:

Task

Description

CalculateCloudMaskForProduct

Calculate a cloud mask for the following sensors: Landsat 4-5 TM, Landsat 7 ETM+, Landsat 8, Sentinel-2, and NPP VIIRS reflectance/thermal data. It automatically performs the radiometric calibration required for the Fmask algorithm. You do not need to calibrate the imagery before executing this task.

QueryAllTasks

This task returns a hash where each key is the task name and each key contains a hash of the task's properties.

RGBToHSIRaster

Transform the color space of a raster from red/green/blue (RGB) to hue/saturation/intensity (HSI).

The following objects and methods are available:

Object/Method

Description

ENVICalibrateRaster

Construct an ENVIRaster from a source raster that has been calibrated to radiance, top-of-atmosphere (TOA) reflectance, or brightness temperatures.

ENVIGridLinesLayer

This is a reference to an ENVIGridLinesLayer object. Also see the ENVIView::CreateGridLinesLayer method below.

ENVILayerStackRaster

Create a layer-stacked ENVIRaster from source rasters that have been regridded to a common spatial grid. The source rasters can be band groups within a metaspectral dataset (such as Landsat, ASTER, or Sentinel-2); or they can come from different raster files.

ENVIRGBToHSIRaster

Construct an ENVIRaster from a source raster that has been transformed from a red/green/blue (RGB) to hue/saturation/intensity (HSI) color space.

ENVIGLTRasterSpatialRef::Dehydrate

Return a hash describing these objects. You can use this information in a later ENVI session to restore the objects using the ENVIHydrate function.

 

 

 

 

ENVIPointCloud::Dehydrate

ENVIPointCloudSpatialRef::Dehydrate

ENVISpatialSubsetPointCloud::Dehydrate

ENVIPointCloudProductInfo::Dehydrate

ENVIView::CreateGridLinesLayer

Create grid lines to overlay on a raster or vector layer.

The ENVIGLTRasterSpatialRef routine now acts as a constructor function, allowing you to create a new geographic lookup table (GLT) spatial reference in the ENVI API. You can then open an ENVIRaster using the GLT spatial reference. See the ENVIGLTRasterSpatialRef help topic for details.