Product Information

Software: 

EARTHSCOPE (Version W2.0) 

Release Date: 

June 1997 

Eidetic Digital Imaging Ltd. 
1210 Marin Park Drive 
 Brentwood Bay, British Columbia 
 Canada, V8M 1G7 
 250-652-9326 
 250-652-5269 (fax) 
eidetic@eidetic.bc.ca (e-mail) 
 www.eidetic.bc.ca/~eidetic 

Prices: 

Hardware Requirements 
Computer Platform: 
 

• IBM PC or compatible 486 Pentium microcomputer with mouse 
• Operating System: Windows 3.1 or Windows95 
• minimum RAM:  8MB 
• GraphicS:  24-bit VGA display adapter operating in 640 by 480 mode 
• Hard Disk Space:  @3MB for the Earthscope software plus image file storage space (dependent upon size of image files). 
• Floppy DISK Drive: 3.5-inch high-density disk drive 
• Distribution Medium: 3.5-inch diskettes 
• Output:  Any printer compatible with the computer and Windows operating system. 

ASPRS does not endorse nor take any position concerning this review. The views and opinions expressed herein are solely those of the author and do not reflect the views and opinions of ASPRS. 

Earthscope was developed from an earlier Eidetic image processing package entitled “RSVGA,” which ran under the DOS operating system.  Earthscope has been written to take full advantage of the greater capabilities of modern microcomputers and the utility of the Windows operating systems.  This reviewer has used Earthscope for personal image analysis of remotely sensed data with image files as large as full scene Landsat thematic mapper data (approaching 8000 by 8000 columns and rows of pixels).  Although the maximum size of an image to be analyzed by Earthscope is 8160 by 8160 rows and columns of pixels, images can be extracted from original scenes as large as 16,000 by 16000 rows and columns of pixels.  In addition, I have used Earthscope in my undergraduate remote sensing classes where students seem to quickly understand the various operations of the image processing system.  This means that students are not hung up with problems of computer operations, and can focus upon the subject of the image processing exercise (e.g., mapping the wetlands, determining the thermal temperature difference between urban and rural landscapes, or finding the total area of woodland within the imaged area). Today’s students are very familiar with the Windows format.  They have little difficulty using Earthscope even without formal introduction to the software.  Within Earthscope, opening files and dealing with the image processing operations is quite intuitive.  Although extensive help menus are available, and a printed manual is also available, these are seldom required.  When there is a question of software operation, the help screens usually get one on track very quickly. 

Earthscope provides the ability to download data from CD-ROM, hard drive, zip drive, or other storage media.  Original data files can be as large as 16,000 by 16,000 rows and columns of pixels, but a maximum of 8,160 by 8,160 rows and columns of pixels can be accommodated by Earthscope.  One can choose any smaller subset area of the original larger image.  All remotely sensed data are stored in one large “image” file.  This file will hold up to 25 individual “pictures,” each picture being one of the spectral bands, enhanced images, or classified images.  This format of data storage is very efficient and easily used once encountered.  Individual pictures can be moved or deleted within the larger image file.  If 25 pictures is not enough, one can copy this image file to one of another name, delete unneeded duplicate pictures, and continue with new storage space. 

In addition to the above data input functions, Earthscope has the ability to output data in a variety of ways.  Data can be exported as general image files in the Eidetic fast format, or as BMP files, or TIFF files.  These exported images can be printed to paper by a variety of software, including Windows Paint. The Eidetic fast format data export produces an image file which is readily imported into other image processing software packages. 

Features
Earthscope software is comprised of seven modules.  To outline the functions of these modules this reviewer has borrowed directly from the Eidetic website.  Thus, the features of the Earthscope software are: 

Display Functions

• 8-bit or 24-bit 
• create color composite 
• pixel value read-out and zoom 
• display of bands side-by-side or full screen 
• pseudo-color, true-color, false-color 

• select a look-up-table 
• create and load a custom pseudo-color table 

• select a view window 
• display or clear a page 
• clear the display memory 

• principal components 
• low-pass, high-pass, and user-definable filters 
• arithmetic functions such as linear combination of two bands, multiplication of two bands, division of two bands, division of one linear combination by another, addition of a constant, multiplication by a constant 
• histogram of a band, plot of the histogram 
• contrast stretch, histogram equalization 

• selection of calibration and test data polygons with zoom  maximum-likelihood classifier 
• minimum-distance classifier 
• parallelepiped classifier 
• tabular and visual (graphical on the screen) error reporting 
• deletion of calibration and test polygons 

• K-Means with automatic centroid determination  interactive centroid determination on 2 bands 
• density slice 

• affine and quadratic transformations 
• image-to-map transformations 
• image-to-image transformations 
• scale transformations  residual display and control point adjustment with zoom  interpolation by nearest neighbor, bilinear, or cubic convolution 

• data import/export 
• extract smaller images from larger images up to 16K by 16K 
• process images up to 8000 by 8000 pixels 
• point and click user interface 
• on-line help manual 

A subset of the Earthscope package is also available as a separate product called PEDAGeOG and mention of it should also be made in this review. PEDAGeOG was developed by Eidetic Digital Imaging Ltd. to accompany the Geo/SAT project for basic classroom use.  The Geo/SAT project (Geography for Student Applications and Training) is a joint project of the National Council for Geographic Education (NCGE), Space Imaging, and Eidetic.  The objective is to provide a series of environmental and satellite-based instructional modules for various high school and undergraduate curricula.  The Remote Sensing Task Force of the NCGE developed the Teacher’s Manuals, Space Imaging provided the Scholar Series Landsat Thematic Mapper satellite data for selected areas, and Eidetic developed the PEDAGeOG software for the analysis of the satellite imagery.  The three components form an inexpensive integrated package.  This sofware and associated materials were reviewed in the October, 1995, issue of Photogrammetric Engineering and Remote Sensing.  PEDAGeOG has now been re-written for the Windows operating system.  It is a fully functional digital image processing system but is not as complete as Earthscope.  In general, PEDAGeOG does not have the image classification and geometric correction capabilities of Earthscope.  On the other hand, the data sets and Teacher’s Manuals for all the sites (Yellowstone fires, Charleston wetlands, Chernobyl’s nuclear accident, Persian Gulf oil spill, and Mississippi flood) can be used with both PEDAGeOG and Earthscope.  For more details about PEDAGeOG and Geo/SAT, refer to the Eidetic website at http://www.eidetic.bc.ca/~eidetic. 

Performance 
This reviewer has used Earthscope on several IBM compatible PC microcomputer platforms.  These include a DEC Venturis 575 75 megahertz Pentium computer, a Hewlett Packard Pavilion 8240 233 megahertz Pentium computer, a Dell Optiplex 300 megahertz Pentium II computer, a Gateway 486 DX66 66 megahertz computer, and several Gateway pentium and 486 computers in a student access laboratory.  In all cases Earthscope has worked flawlessly, with one exception.  Our older Gateway 486 laboratory machines have ATI video boards containing the 8514 graphics chip.  In this configuration Earthscope was unable to display images because the 8514 does not have a 24-bit display capability. All other functions seem to run without a problem, but new 24-bit video boards would be needed to make these older computers compatible with Earthscope; such boards can be obtained for as little as $50, and all newer computers come with them. 

In general, while running tests on the same remotely sensed data, Earthscope ran faster and smoother than other image processing systems this reviewer has available.  This list of other software includes Erdas, Idrisi 4.0 and Idrisi for Windows Version 2.0.   It is important to note that students seem to find Earthscope (and PEDAGeOG, see above) much more intuitive and easier to use than any other image processing software I have tried in my remote sensing classes. 

Documentation
Earthscope includes a complete on-line help system that actually includes the complete operating manual.  This on-line help is in the standard Windows format including contents, search, and the ability to print sections of the help documentation.  The printed manual is concise, fully functional, and without noticeable errors.  The manual includes installation instructions, which are very easily followed.  A short tutorial for all operations is also included.  This documentation is not a digital image processing text.  It does a good job of informing the user how to accomplish each software function, but does not attempt to explain why the user would want to use each function.  This last is the purpose of digital image processing text books and exercise manuals. 

Technical Support 
Eidetic Digital Imaging has offered the following statement concerning technical support for Earthscope: “Telephone, fax, and e-mail technical support is available for as long as the customer has the license.  It is included in the price of the license but telephone toll charges are the customer’s responsibility.  E-mail support is recommended.  The stated objective is to provide a response within 48 hours.  The operative principle is that considerable effort has been expended to ensure that Earthscope is bug-free and to minimize the probability of user difficulties arising, but if a customer does encounter a difficulty then the customer should not have to pay more to Eidetic to resolve the difficulty.” 

This reviewer has found that technical support for Earthscope is seldom required, but when needed is often more complete and useful than that which accompanies image processing software costing much more. 

Ease of Installation
Earthscope is very easy to install.  Complete instructions for Windows 3.1 and Windows 95 are included in the manual.  Installation takes only a few minutes, and requires nothing unusual.  Just put the first of three diskettes in the 3.5 inch disk drive and run “install”. 

Operational Highlights 
Earthscope takes full advantage of the point-and-click features of the Windows operating system.  An example of typical image processing follows to illustrate some of the valuable characteristics of Earthscope.  Obviously, this image classification example is not a comprehensive review of all the capabilities of Earthscope, but is an example of a typical process of digital image analysis. 

1. Import seven Landsat TM spectral band files into the “Pictures” of the Earthscope “image file.” 
Earthscope allows the operator to open the original data files in a manner common to the Windows operating system (e.g., click on the drive and file name, etc.).  A subregion of the original data set can be outlined and registered samples of all seven spectral bands can be installed in the Earthscope “image file”. 

2. Enhance the raw data for visual viewing and interpretation. 
Linear or histogram equalization data stretching options are available.  Just clicking on the enhance menu, and then histogram equalization, allows one to click on the input raw data band, and identify the “picture” to write the new stretched data scene.  Minimum and maximum DN values are displayed, but can be designated by the operator. 

3. Select a window for viewing and display the images. 
Earthscope will display the total imaged area with a box to be dragged by the mouse to the location of  prime interest.  Column and row coordinates of the box are displayed.  The display options allow one to display the area of interest with a view of  632 by 452 pixels, or a more detailed  316 by 226 pixels.  Up to four monochrome scenes can also be displayed  simultaneously on the monitor if desired.  In addition, one can create three-band color composite images, which can also be saved in a separate set of 25 “pictures.” 

4. Arithmetic operations. 
For further image enhancement several options are available, including principal component analysis, convolutions, and image algebra.  Image ratioing to produce output such as a normalized difference vegetation index is extremely easy, with final output written to a “picture” of the “image” file.  One is also able to plot the histogram of a “picture”, and, by moving a cursor across the X-axis, determine the percent of pixels having DN values greater than or less than the value of the cursor position. 

5. Pixel read-out and Zoom.
A very handy tool within Earthscope is the ability to view an image (either monochrome or color composite) with a utility which allows the operator to place the cursor on any pixel and determine the pixel’s digital value (or the red, green, and blue values in the case of color composites).  The mouse buttons allow one to zoom in and out while performing the digital readout.  This is useful when interpreting specific features and phenomena. 

6. Choosing training sites for supervised image classification. 
For each training site Earthscope allows the operator to choose any “picture” as background (monochrome or color composite).  Once a class number is assigned, the operator can use the mouse to locate and zoom to the training site for best visual acuity.  Then, after striking the “D” key for “digitize”,  the mouse can be used to draw the irregular outline of the training site polygon.  After all training sites have been digitized Earthscope will write the training data to an ASCII file, and will also save a “picture” file of training sites. 

The fact that Earthscope allows irregular training polygons, and that the DN values are tabulated in a separate file, makes this utility very useful for extracting digital data concerning emittance and reflectance values of target sites within an image. 

7. Image classification. 
Earthscope provides several classification algorithms, including parallel-piped, minimum distance, and maximum likelihood.  For unsupervised classification there is a k-means unsupervised clustering classifier, plus a two-band visually interactive classifier and a single band density slice option.  The sensitivity of these classifiers can be adjusted by changing the alpha level or standard deviations used in selecting pixels to be assigned to various classes. 

8. Image output. 
Classified images can be displayed and the colors assigned to the classes can be reassigned with user defined pallets.  Earthscope provides the option of exporting digital files of images and classified images in several formats as discussed above.  Printing of  these images is accomplished using Windows software utilities. 

This reviewer has performed all of the above operations on a seven band 1000 x 1000 pixel set of remotely sensed data in less than 20 minutes, using a 233 megahertz microcomputer. 

Recommendations 
Earthscope provides a very capable image processing system at an inexpensive price.  It is a good software package to be used for instructional or professional purposes.  In addition, this software can augment other image processing packages, by providing utilities or more efficient processing where other software may accomplish a task in more awkward, or more inefficient, ways. 
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