James S. Aber
The following instructions are intended to supplement the tutorial exercises supplied with Idrisi Selva. The tutorial exercises are found in a pdf file--see Idrisi Selva Tutorial, by J. Ronald Eastman (Idrisi Selva\Documentation\Idrisi Tutorial.pdf). See also Idrisi Manual, by J. Ronald Eastman (Idrisi Selva\Documentation\Idrisi Manual.pdf). The term selva refers to dense tropical forest.
Students should follow the step-by-step procedures provided in the tutorial exercises (Idrisi Tutorial.pdf), except as noted below. Additional hints or suggestions are given according to lettered sections of the tutorials. Numbered questions are given below for some exercises. Students should provide written answers for these questions.
To turn in exercise results, students should submit digital files (as e-mail attachments). For text files, plain (ascii) text (txt) or rich text format (rtf) are acceptable formats. Do not send WordPerfect, Microsoft Word, or other proprietary formats. Image files can be sent separately as bmp, gif, or jpeg formats. Do not embed image files in text documents.
| Exercise 1-1 | Exercise 1-2 |
| Exercise 1-3 | Exercise 1-4 |
| Exercise 1-5 | Exercise 1-6 |
| Exercise 1-7 | Exercise 1-8 |
| Exercise 2-2 | Exercise 2-3 |
d) Idrisi files, maps, images, and related data are organized according to projects. These projects consist of files arranged in working folders and resource folders which are accessed during project operations.
Note: in the GSA lab, several students may use Idrisi on the same computer. Be sure to check the project environment every time, to be sure you are working in your own folder. Furthermore, Idrisi software is in "deep freeze" on these computers, so that each time Idrisi is started it begins in the default mode.
o) The x and y values for this map indicate geographic positions in the UTM grid system. The representative fraction (RF) is the map scale as displayed on the monitor. The scale thus depends on monitor settings (resolution) as well as the size of the map display.
1. What the units for the x and y values? Explain what the UTM numbers are and actually mean.
2. What is the RF for the SIERRADEM map in its original display size?
3. In step p), click the icon for Full Extent Maximized (9th icon from left). What happened to the image? What is the new RF?
q) This section introduces new Idrisi on-screen functions, measure length and measure zone. Experiment with these functions.
4. What is the distance from the upper left corner of the map to the lower right corner? What are the units of measurement for distance and for area on this map?
v) At this point, you should have a map composition that resembles the following example, which is a digital elevation model for a portion of Spain. Elevation is displayed by a combination of colored classes and contour lines. High elevations are depicted in hot colors (red, orange, yellow) which appear to stand up above the cool colors (blue and green) of lower elevations. This is a color stereographic effect.
d) Raster and vector data structures are fundamentally different ways to define geographic space.
1. In your own words, describe the structure of raster datasets.
2. In your own words, describe the structure of vector datasets.
f) Following this section, save an image of your map composition showing the forest vector overlay as a dark-blue cross-hatched pattern on the forest NDVI image. Give your composition a suitable title, including your name and date, and save an image file (bmp). Name the saved image "sierraforest."
h) This is another example of false-color composite (see above). In this case, the selected bands and color coding produce an image in which active vegetation has yellow-green to dark green colors.
Remember: Set the working folder to your personal student folder, and designate the Idrisi Tutorial\Using Idrisi\ folder as the resource folder.
1. What is the apparent direction of solar illumination for the hillshade image?
c) At the end of this section, you should have a map that resembles the following example. This composition includes a digital elevation model, hillshade image, and pale blue contour lines, with a legend that shows contour intervals. If your image does not look like this one, back up and repeat the procedures of part c).
e) The RECLASS icon is actually fifth from right across the top tool bar.
f) You should add the LAKES raster image to your previous sierra_blend map composition.
g) After completing your display of lakes on the Sierra terrain model, you should have an image that resembles the following example. Note the pale blue lakes imposed on the color-coded elevation map. If not, back up and repeat the procedures of steps f) and g).
2. Compare this false-color composite with previous images of this same region. What color is active vegetation?
3. Why do you suppose the lakes appear black in this false-color composite image?
i) This visual effect is also called parallax. When the same scene is photographed or viewed from different vantage points, the relative positions of objects appears to be offset. This is the basis of stereoscopic vision in humans, which allows us to perceive depth. Ikonos is a commerical satellite system that provides high-resolution imagery in visible and near-infrared portions of the spectrum. The resolution of these images equals conventional airphotos, as this example demonstrates. See Ikonos.
j) For proper depth perception, place the red filter over left eye and cyan filter over right eye (see top drawer map case). Maximize the image display and zoom in for best effect.
4. Describe the appearance of the anaglyph image.
Remember: Set the working folder to your personal student folder, and designate the Idrisi Tutorial\Using Idrisi\ folder as the resource folder.
1. What is a triangulated irregular network (TIN)?
d) The drape image is a false-color composite Landsat image in which active vegetation appears in pink/red colors. The necessary flight file (sf.csv) is located in the Using Idrisi resource folder. This flight begins to the south in the vicinity of San Jose and Santa Clara and proceeds northward into the San Francisco Bay region; the Bay area is home to several million people.
2. Notice the bright cyan-green colored areas near the southern end of San Francisco Bay in the vicinity of Newark. Identify what these features are; you may have to do some online research.
g) Following this step, create a block model of the scene using ORTHO. Select SIERRADEM as the surface image, and pick SIERRAILLUMINATED as the drape image. Choose output resolution of 800 x 600. Name the output image "sierrafire." Leave other options in default values, and click OK.
Add an appropriate title and subtitle (your name and date). North arrow and scale bar are generally not included on this type of perspective view. Note: change background of titles to black, matching the background of the image, and change font color to silver. Save a digital image file to turn in.
Remember: Set the working folder to your personal student folder, and designate the
Idrisi Tutorial/Using Idrisi folder as the resource folder.
1. What is a "primary" color? What is the "additive" nature of primary colors?
b) Be sure to display these images from the Sierra group. Click off legend for these displays.
2. What is autoscaling? How does it work?
f) The Group Link icon is 11th from left on the tool bar, and Placemarks is the 12th icon.
Remember: Set the working folder to your personal student folder, and designate the Idrisi Tutorial/Using Idrisi folder as the resource folder.
f) The "Captions text" input box is found under the "Titles" tab of Map Properties. Follow instructions. Then add your name and date in the input box for "Subtitle text." Select Arial font, maroon color, bold, and size = 12. You may have to move and resize title and subtitle components on the map composition in order to achieve effective placement. Make sure titles do not overlap parts of the map or other components.
g) The WESTBORO.BMP file is located in the Idrisi Tutorial/Using Idrisi folder. The graphic image may not be visible at first; it could be hidden underneath the main map image. Move the map image to locate the graphic inset image. Next move the graphic inset image below the roads legend, then move the main map back into its original position.
Note: the graphic image should be the same shape as the raster "base map" image--approximately square. When moving or resizing the inset image, make sure to retain its square shape.
h) You might want to give the scale bar larger font, depending on its visibility and the resolution of your monitor. Note: sometimes the scale bar does not display properly, or it may cause other components (graphic inset) to move. Remember to turn off the Auto-Arrange function in the map composer. Position the scale bar just above the graphic inset. Your composition should resemble the following example.
l) Skip this step. It is assumed that North is upright on the map, so an arrow is not necessary. In those cases where North is not straight up, an arrow should be included.
m) Add your name and date in a subtitle in upper right margin of the composition, and be sure to save a map composition!
n, o) Your WESTBORO map composition file should be located in your personal working folder.
p) Instead of printing a paper copy, students should save a graphic image. In the Save
Composition menu, select "Save to Windows bitmap (BMP)." Enter WESTBORO as the file name, and
click OK. The bmp file will be saved in your personal working folder.
Idrisi Taiga cannot display bitmap images directly, but you can view your bmp image with any
graphics software, such as Paint, Adobe Photoshop, etc. Display the WESTBORO.BMP file
with available graphics software. It should look identical to the Idrisi map composition. Use
the image attributes or size function of your graphics software to determine the number of rows
(height) and columns (width) in pixels for the bmp image, for example 800 columns by 600 rows.
Change the file type to "256 Color Bitmap" selection, and enter a new file name, such as WESTBORO-256. Click the "Save" button. A warning message will appear; click "Yes" to continue.
Remember: Set the working folder to your personal student folder, and designate the Idrisi Tutorial/Using Idrisi folder as the resource folder.
g) Your palette workshop should look like the following example.
2. Why is a continuous palette suitable for displaying a digital elevation model (DEM)?
m) Following this step, you might want to save a preliminary map composition (*.map file). Do this periodically as you move through the exercise.
n) After selecting "text" type and entering the new file name, click OK. The symbol workshop will reappear with a matrix of cells. Click on cell 0 (zero). Another dialog box will appear, in which you can choose font characteristics.
p) Be sure to select PROVTEXT as the symbol file. For the first province name, enter "Tigray" (not all caps), and continue the same way for other provinces. Note to select "specify rotation angle" and leave at default options (center, 90°).
q) Notice that each province name appears in a different color according to the qualitative palette. Labels will change to maroon color when the composition is redisplayed.
r) This procedure is a bit tricky. You may have to try a couple of times to rotate the Shewa label. Your result should resemble the following example.
t) Additional map components include an appropriate title, subtitle with your name and date, scale bar, and north arrow. Under titles, select the caption option to create a caption for the legend. Place the north arrow in the upper-left corner of the black map area; locate the scale bar in the lower-right corner of the black map area.
Note: the order in which you add components is important. Save the north arrow as the last thing to add, after titles and scale bar. You should change background and font colors to place legend caption, scale bar, and north arrow on the black background. The background should be all black in the final composition.
Notice: Idrisi does have some issues for editing or revising existing map compositions. Often the scale bar, north arrow or legend does not appear properly. If this happens, it's best to start over rather than trying to fix a defective composition.
3. Why does the scale bar show degrees instead of a linear measurement, such as meters, kilometers or miles? Hint: see etdem.rst metadata.
u) Along with the map composition, save a digital image file, named ETHIOPIA.
v) Maximize image size for this display. This Landsat false-color composite of Las Piedras, Venezuela utilizes visible (3) and infrared (4 & 5) spectral bands and color coding so that active vegetation appears in green and yellow-green colors. Bare rock, soil and pavement appear in pink, brown and maroon colors; water bodies are bright blue to black. Note: dark cloud shadows.
w) You may expand or move each photo window to improve the view and see the full title. The photo layer is an excellent tool for field operations and ground-truth observations. Notice the extremely steep terrain in this region of the Andes Mountains, which is not readily apparent in the Landsat image.
Remember: Set the working folder to your personal student folder, and designate the Idrisi Tutorial/Using Idrisi folder as the resource folder.
b) WESTLUSE and ETDEM raster files are located in the Idrisi Tutorial/Using Idrisi folder.
c) Right click in the "All Idrisi Extensions" pane to "Select All."
e) Read through this long section carefully.
1. What are ASCII and UNICODE file formats?
g) Examine the metadata for ETDEM and note the entries for reference system, reference units, min/max x and y, min/max value, resolution, and value units. The distinction between these file attributes is important.
2. Explain the meaning of reference system, reference units, min/max x and y, min/max value, and value units in the ETDEM metadata file.
3. Why are reference units in degrees and value units in meters?
4. What do the values for resolution represent?
j) The histo icon looks like a little bar graph to the right side on the tool bar. Once the histogram is displayed, click the "Save to Clipboard" button (lower left corner); you can then paste the image into Paint to save an image file of the histogram. Turn in this histogram with your answers.
n) The term "double precision real number" is mentioned in this part. Look up the meaning of this numerical format in the Help/Contents--see file structures: vector file.
5. What is the difference between single and double precision real numbers?
Note: Answers for the numbered questions (1-8) in the tutorial are given at the end of the exercise. Be sure to confirm your answers at each step.
After working through the exercise step by step, you should build a complete macro model to run the procedure from start to finish--input files to PLOTS. Do not include AREA or EXTRACT operations. See p. 64, and consult Figures 4-9 for guidance.
Build your macro model from left to right, and test it each time you add a new element. Save the file, and run. A warning message may appear about overwriting existing files; click "yes to all" button. As you are building the macro model, arrange the components into a neatly organized flow chart, similar to the tutorial examples.
Once you have completed a successful macro model, save the model diagram. Under "File" click "Save to clipboard" option. Then open the Windows program Paint, and paste the image into Paint. From here you can save the image as a jpg or gif file to turn in.
Skip the section on "Using image calculator ..." (p. 66).
As your final task, make a map composition of the suitable soil plots for sorghum. The background should have a dull brown color, and each plot should have a distinctive yellow, orange or green color. You will have to make a special palette using the Symbol Workshop (3rd icon from left). The composition should include a suitable title, subtitle with your name and date, legend and scale bar. Save an image file to turn in.
Exercise 1-1. The IDRISI Environment
This tutorial introduces the basic working environment for Idrisi.
The working folder is the location where files may be input or output. This is the folder where map and image files may be saved. Only one working folder can be accessed for a project. The resource folder is a location from which files can be accessed and brought into a project session. However, files cannot be saved to a resource folder. Several resource folders can be open during a project session. In this way, available map and image files can be input from several resource folders as well as the working folder for an Idrisi project.
Set the working folder to your personal student folder at this time. Right click in the Projects panel, browse for your personal student folder, and select it for the project. Note that it appears as the working folder in the Editor panel. Now, right click in the Editor panel to create a resource folder. Click in the blank box (button on right), browse to the Idrisi Tutorial Data\Using Idrisi folder, and select it. Add another resource folder for Idrisi Tutorial Data\Introductory GIS. Keep in mind these changes in the project environment.

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Save the resulting image as a bitmap (bmp) file using the Composer box. You should now be able to display the bitmap file with any graphics software, such as Paint, Adobe Photoshop, etc.
Turn in:
Exercise 1-2. Display: Layers and Group Files
A map may display many "layers" of data, such as land use, political boundaries, streams and lakes, soils and geology, transportation routes, elevations, etc. This exercise demonstrates how a map is constructed from raster and vector layers. The method of group files is also introduced. The approach allows simultaneous access to data from related datasets for the same map area.
Your image should resemble this example.
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Exercise 1-3. Display: Layer Interaction Effects
Advanced layer display effects include blends, transparency, anaglyphs, and composites. These visualization techinques are demonstrated in this exercise. Hillshade and reclass operations are introduced as well.

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Exercise 1-4. Display: Surfaces -- Fly Through and Illumination
This tutorial demonstrates the ability to visually "fly through" a simulated 3-d terrain.
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Exercise 1-5. Display: Navigating Map Query
This exercise deals with map queries, that is obtaining information from map layers about specific features (polygons or cells) of interest. The ability to query map information is enhanced by using data layers from a group collection.
After completing step g), return to the "full extent normal" display (8th icon from left on tool bar). Now zoom in on the large lake in the upper right corner of images. Position the three images, so that the lake in each is clearly visible. Add your name as the subtitle for one of the images. Your working window should resemble the following example.
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Exercise 1-6. Map Composition
An effective map display consists of much more than the map image itself. Standard accessories include a scale bar, legend, north arrow, titles, captions, and date. The "map" often contains several layers of information that are overlaid for visual display, as you have seen in previous examples. This exercise deals with building map compositions from these various components.
Following step b) You should have a map composition similar to this example. The composition consists of a raster layer as the "base map" plus two vector overlays. Also included are a title and a legend for land use.
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Now check the size of the bmp file in bytes. Use your computer's file management to view file
details. Note: one kilobyte (KB) = 1024 bytes. Compare the file size (in bytes) to its size
in terms of the number of pixels (rows x columns).
Now open the WESTBORO.BMP file using Paint software (under Windows Accessories). Under the File menu, select the "Save As" option. Notice the file type given in the input box at bottom of window. The current file type is listed as "24-bit Bitmap." This is so-called true color, in which red, green, and blue color values are stored for each pixel in the image. Each color value is stored as one byte (8-bits), so 24 bits are required per pixel.
BMP files are large in size, as a numerical value is stored for each pixel in the image. This is often redundant, as adjacent pixels may have identical values. More compact storage is possible with various graphics compression formats, such as graphic interchange format (GIF), joint photographic experts group (JPEG or JPG), and other formats. Convert your bmp file to one of these formats using your graphics software.
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Exercise 1-7. Palettes, Symbols and Creating Text Layers
A typical GIS database contains spatially georeferenced information about certain attributes or features. This numerical dataset cannot be displayed on its own. In order to create a display, the geographic dataset needs to be translated into colors and visual symbols. In addition, map displays often contain text labels—names of cities, rivers, soils, provinces, etc. This tutorial deals with the creation of color palettes, symbol files, and text layers.

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Exercise 1-8. Data Structures and Scaling
GIS databases come in two basic types--raster and vector, which require quite different file formats and structures. This tutorial explores the characteristics of files employed in Idrisi for these data types. The tutorial also deals with means for "scaling" data values for display.
Following step (l), create a new false-color composite for the Sierra Landsat dataset. Find and open the COMPOSITE icon (4th from left on tool bar). Enter sierra2 as the blue band, sierra5 as the green band, and sierra7 as the red band. Sierra2 actually represents green light, sierra 5 and 7 are both mid-infrared radiation. Name the output file sierra257, and enter a suitable title. Leave other options in default mode, and click OK. 
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Exercise 2-2. Datebase Query
This exercise deals with extracting information from multiple layers of data, such that compound conditions can be identified. In this case, the combination of elevation and soil type is necessary for determining the feasibility of an agricultural project. You will utilize the cartographic model approach to building a sequence of operations to be carried out on the datasets. See Tutorial 2-1 for an explanation of cartographic models.

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For the final map composition, create a special palette in which the unsuitable background is a dull green color and the suitable area appears bright yellow-orange. Additional elements to include are a title, subtitle (your name and date), legend captions, north arrow and scale bar (with appropriate units). Turn in your final composition as a digital image file.
Turn in:
Return to ES 351,
ES 551,
ES 555,
ES 771, or ES 775.
© J.S. Aber (2012), Emporia State University.