Erdas Er Viewer

[Abigail Tyrie]

ERDASEarth Resources Data Analysis) is a well known and widely used Image Processing Software. It has many in build functions for automatically processing digital data collected from many satellites.

The ERDAS IMAGINE Viewer is the "main window" for displaying raster, vector, and/or annotation data. You can open as many Viewers as your window manager supports There are two kinds of viewers available in IMAGINE Viewer

1. Click SESSIONS Menu on the Main Menu

2. Click on the PREFERENCES option to get the Preferences Editor Window

3. Select USER INTERFACE & SESSION option

4. Now change the Default Data Directory path as D:\ERDAS_Exercise_Files

5. Similarly, Select the VIEWER Option

6. UNCHECK the Clear Display option. With this option user can display more than one image on the Viewer

7. Click on the USER SAVE Button to save the selected preferences

8. Click on CLOSE to Close the Preferences Editor Window

ERDAS ViewFinder is a viewer for quickly displaying a variety of geographic imagery, rapidly reprojecting different data types into the same projection system, displaying multiple images in a single viewer, and working in multiple open viewers, at the same time.

ERDAS ViewFinder uses technology developed by ERDAS for Stereo Analyst and ERDAS IMAGINE, such as embedding multiple views in single windows and reprojecting imagery on the fly.

ViewFinder offers a range of image manipulation capabilities, packaged into a clean, simply designed user interface.

ERDAS ER Viewer is a free, easy-to-use image viewer featuring interactive roaming and zooming with very large JPEG 2000 and ECW files. It can also read most other common file types. Installing ERDAS ER Viewer also lets you embed large geospatial images in your Microsoft Word documents.

The format we are calling ERDAS_IMG to distinguish from other uses of the .img file extension is a proprietary, partially documented format for multi-layer geo-referenced raster images developed originally for use with ERDAS IMAGINE software. This format is used widely for processing remote sensing data, since it provides a framework for integrating sensor data and imagery from many sources. This description covers all chronological versions of the format because the compilers of this resource have been unable to find documentation that clearly distinguishes between formats as produced by different versions of the software. Comments welcome. This format is one of the formats used for data delivery via the National Map as of early 2015, in particular for the National Elevation Dataset (NED).

Another key feature of the ERDAS_IMG format is that it is designed to store technical and georeferencing/geocoding metadata from the source data imported as layers. This supplies a record of provenance. See External File Format Header Object Types.

ERDAS IMAGINE software uses a tiled format to store raster layers. The tiled format allows raster layers to bedisplayed and resampled quickly. The default tile size used to be 64 pixels by 64 pixels, but now appears to be 512 pixels by 512 pixels. Within a tile, raster data uses the BSQ_enc ordering for pixels. Optionally, a large raster layer may be organized in a "pyramid" for faster processing. In pyramid layers, reduced, subsampled raster layers are created from the originalraster layer.

ERDAS_IMG is based on a Hierarchical File Format (HFA) structure. Many of the items that can be included are optional. In addition, because of the open nature of the HFA format, developers may create and add new types of items to the file. Raster layers may be compressed using a variant of Run Length Encoding known as Dynamic Range Run Length Encoding.

For images requiring more than 2 Gbytes of disk space (although some sources indicate that the limit is now 4 Gbytes), a two file dataset is required. The .img file contains the usual structure of headers and structural metadata but the actual image data is kept in a separate non-HFA file format, known as a Large Raster Spill File, with the extension .ige.

Various government agencies and projects distribute data in ERDAS_IMG format, including: the Multi-Resolution Land Characteristics (MRLC) consortium; the Coastal Change Analysis Program, and the National Elevation Dataset. Accompanying metadata sometimes mentions a particular version, presumed to refer to the version of ERDAS IMAGINE used to create the files. For example, the National Land Cover Database from MRLC, uses version 9.3.

Viewing the ERDAS_IMG multi-layered images requires specialized software. A free desktop viewer, ERDAS ER Viewer is available from Hexagon Geospatial. ERDAS_IMG files can be viewed in GeoViewer, freely downloadable from Extensis, formerly LizardTech. ERDAS_IMG files can be read and written by ArcGIS Desktop and other ESRI applications. See Supported raster dataset file formats from ArcGIS help. It is also supported by Safe Software's FME engine for format conversion.

As of January 2015, ERDAS IMAGINE software is distributed by Hexagon Geospatial, which is part of the Intergraph Corporation. Intergraph is in turn part of the Hexagon conglomerate, which acquired Intergraph in 2010.

The Landsat team recommend a workflow (Link via Internet Archive) using an ERDAS_IMG file as an intermediate file in order to fill in pixels that are missing in source images from Landsat 7. The final output of the workflow is a GeoTIFF image designed to be aesthetic rather than scientifically precise. Preparing Image Base Maps for the Digital AerialSketchmapping (DASM) System, from the U.S. Forestry Service, provides instructions for another map-making workflow. This workflow outputs the ERDAS_IMG file as well as files in JFIF_1_02 (JPEG File Interchange Format) and MrSID formats.

See Hexagon: Our History (Link via Internet Archive) for the complex chain of corporate acquisitions. The Internet Archive reveals a view of the complex branding context for ERDAS IMAGINE over the years. A website for ERDAS, www.erdas.com, was first captured by the Internet Archive in 1997. The company described itself as a "mapping software company specializing in Geographic Imaging solutions since 1978." The version of ERDAS IMAGINE was 8.3. The company description in August 2008 indicates that ERDAS was acquired by Leica Geosystems in 2001 and that Hexagon had acquired Leica Geosystems in 2005. ERDAS IMAGINE 2009 was version 9.3. By June 2012, www.erdas.com redirected to geospatial.intergraph.com. As of January 2015, the earlier URLs redirect to www.hexagongeospatial.com, a site first crawled by the Internet Archive in May 2014.

ERDAS ER Mapper professional software is used worldwide in the oil, gas, and mineral exploration industries for satellite and aerial image exploitation. Working from raw data, immediately applying processing and enhancing options, and real-time response are distinctive advantages that ERDAS ER Mapper provides to users.

ERDAS ER Mapper provides unique geoprocessing tools for enhancing and visualizing surface interpretations, and integrating data from a variety of sources -geophysical, geochemical, satellite, digital terrain, radar, airphotos, scanned maps, vector GIS and other data- to create top quality map products.

ER Viewer

ERDAS ER Viewer a free easy-to-use desktop image viewer application and Microsoft Office Plugin, that enables you to interactively roam and zoom in JPEG 2000 and ECW files.

No idea, sorry. It seems to happen only sometimes and cannot determine what is the problem. I have no idea what happens if other objects are added because we only use single volumes (microCT volumes).

I noted that even the View>Centre> commands sometimes make no difference.

I know that my comment is pretty useless for debugging but at least I can confirm that there seems to be some kind of intermittent problem.

This might explain why some users only experience the issue with larger objects that fill the viewer. In this case it is difficult not to click on the object, and thus inadvertently select it, while dragging,

The Annotation Tool menu will appear. Click on the Create Text Annotation button in the menu Now move your cursor in the viewer where you want to place text. Single click and a window will appear for you to enter a text string. When you are done entering text, click OK. Now select the text by clicking it. A double click with the mouse will bring up the Text Properties window. You can move the text by selecting it (lmb) and sliding it around while holding the lmb down. A box will appear around the text string and you can also alter the size by selecting the box and manipulating it...experiment. If you want to make any changes in font style, color etc., make them while the text is selected and apply them. To de-select text, select an area on screen away from the text. You can change the text style by clicking on the Display Annotation Styles button When the Styles window appears, open the Text Styles menu with the rmb and choose Others... The Custom folder will give you several options to choose from including fill color, font style, and size. Use this tool to make your choices about the text you will place in the annotation layer. You have the ability to change the text selections, etc. at a later point as well if you are not satisfied with these original choices. Annotation for images should contain certain entries so that others can tell what has been altered in the image that may be important to how they use it to make decisions. The following items are good to include on an annotation: 1) Your name 2) The sensor system (SPOT, TM, CAMS etc.) 3) Any alterations listed that were done to the image (rectified, filtered etc.) 4) The band assignments to their display colors (R,G,B = 1,2,3 etc.) 5) The date you completed the work on the image (You should display the date as follows: 10 August 1997). This information should also NOT be put on top of the image but off to the side or below it. This is because you would not want the annotation covering up vital parts of the image so that they could not be viewed. When you are finished save the image and its annotation file by selecting Save under the viewer menu File. Part II Map Composer Image (for the trial only)

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