2 Note that user-created palettes are always stored in the active Working Folder. However, you can save them elsewhere using the Save As option. If you create a symbol file that you plan to use for multiple projects, save it to the Symbols folder under the main TerrSet program folder.
EXERCISE 1-7 PALETTES, SYMBOLS AND CREATING TEXT LAYERS 40
Our next step will be to create a set of labels for the provinces of Ethiopia. This will be done by creating a symbol file for the text symbols, and a text layer with the label features.
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Open Symbol Workshop and from the File menu, select New. In the New Symbol File dialog, specify Text and input the name PROVTEXT. Select text symbol 0 and set its characteristics to 12 point bold italic Times New Roman in maroon. Click OK to return to the main Symbol Workshop dialog, and use the Copy button to copy this symbol to all other categories. Then Save the file (from the File menu) and exit Symbol Workshop.We now have a symbol file to use in labeling the provinces. To create the text layer with the province names, we will use the TerrSet on-screen digitizing utility. Before beginning, however, examine the provinces as delineated in your composition. Notice that if you start at the
northernmost province and move clockwise around the boundary, you can count 11 provinces, with two additional provinces in the middle—
a northern one and a southern one. This is the order we will digitize in: number 1 for the northernmost province, number 2 for that which borders it in the clockwise direction, and so on, finishing with number 13 as the more southerly of the two inner provinces.
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First, press the End key to make your composition as large as possible. Then click the digitize icon on the tool bar (the one with the cross in a circle). If the highlighted layer in Composer is the ETPROV layer, you will then be asked if you wish to add features to this existing layer, or create a new layer. Indicate that you wish to create a new layer. If, on the other hand, the highlighted layer in Composer was the ETDEM layer, it would automatically assume that you wished to create a new layer since ETDEM is raster, and the on-screen digitizing feature always creates vector layers.P
Specify PROVTEXT as the name of the layer to be created and click on Text as the layer type. For the symbol file, specify the PROVTEXT symbol file you just created. Specify 1 as the index of the first feature, make sure the Automatic Index feature is selected, and click OK. Now move to the middle of the northernmost province and click the left mouse button. Enter TIGRAY as the text for the label. Most other elements can be left at their default values. However, select the Specify Rotation Angle option, and leave it at its default value of 90°.3 Also, the relative caption position should be set to Center. Then click OK.Q
Repeat this action for each of the remaining provinces. Their names and their feature ID's (the symbol type will remain at 1 for all cases) are listed below. Remember to digitize them in clockwise order. For the two center provinces, digitize the northern one first.2 Welo
3 Harerge
4 Bale
5 Sidamo
6 Gamo Gofa
7 Kefa
8 Ilubabor
9 Welega
10 Gojam
11 Gonder
12 Shewa
13 Arsi
3 Text rotation angles are specified as azimuths (i.e., clockwise from north). Thus, 90° yields standard horizontal text while 270° produces text that is upside-down.
EXERCISE 1-7 PALETTES, SYMBOLS AND CREATING TEXT LAYERS 41
Don't worry if you make any mistakes, since they can be corrected at a later time. When you have finished, click the right mouse button to signal that you have finished digitizing. Then click the Save Digitized Data icon on the tool bar (a red arrow pointing downward, 2 icons to the right of the Digitize icon) to save your text layer.
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When we initially created this text layer, we made all text labels horizontal. Let's delete the label for Shewa and put it on an angle with the same orientation as the province. Make sure the text layer, PROVTEXT is highlighted in Composer. Click on the Delete Feature icon on the tool bar (a red X to the right of the Digitize icon). Then move the mouse over the Shewa label and click the left mouse button to select it. Press the Delete key on the keyboard. TerrSet will prompt you with a message to confirm that you do wish to delete the feature. Click Yes. Click on the Delete Feature icon again to release this mode. Now click the Digitize icon and indicate that you wish to add a feature to the existing layer. Specify that the index of the first feature to be added should be 12.Then move the cursor to the center of the Shewa province and click the left mouse button. As before, type in the name Shewa, but this time, indicate that you wish to use Interactive Rotation Specification Mode. Then click OK and move the cursor to the right.
Notice the rotation angle line. This is used simply to facilitate specification of the rotation angle. The length of the line has no significance—only the angle is meaningful. Now rotate the line to the northeast to an angle that is similar to the angle of the province itself. Finally click the left mouse button to place the text.
If you made any mistakes in constructing the text layer, you can correct them in the same manner. Otherwise, click the right mouse button to finish digitizing and then save your revised layer by clicking on the Save Digitized Data icon on the tool bar.4
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To complete your composition, place the legend for the elevation layer in the upper-left corner of the layer frame. Since the background color is black, you will want to use Map Properties to change the text color of the legend to be white and its background to be black.T
Add any other map components you wish and then save the composition under the name ETHIOPIA.U
Save the ETHIOPIA map composition for use in Exercise 1-8.Photo Layers
A photo layer is a special example of a text layer. It was developed specifically for use with ground truthing. This final section of the exercise will demonstrate using Photo Layers as part of a ground truth exercise in Venezuela. Photo Layers are created as text layers during the on- screen digitizing process, either through digitizing a new text layer or when laying down waypoints during GPS interaction. In both cases, entering the correct syntax for the text caption will create a Photo Layer.
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Using DISPLAY Launcher, display the layer LANDSAT345_JUNE2001. Then, use Add Layer on Composer to add the vector text layer CORRIDOR.
4 If you forget to save your digitizing, TerrSet will ask if you wish to save your data when you exit.
EXERCISE 1-7 PALETTES, SYMBOLS AND CREATING TEXT LAYERS 42
Four text labels will appear corresponding to ground truth locations. The ground truth exercise was undertaken with the goal of creating a land use map from the Landsat imagery shown in the raster layer. During the exercise a GPS was connected to laptop. As waypoints were recorded, photos also were taken of the land cover which could be used to facilitate the classification process.
When the text layer is displayed, text labels associated with photos will be underlined. In our case, the text labels shown are different times during the day, but on different days.
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Using Identify, click on the text location. The photos associated only with that label will be displayed. Only one photo layer label can be displayed at a time. Click on the other text labels and the previous photos will be removed as other layers are displayed.Each photo shown corresponds exactly to the view azimuth at the location where the photo was taken. When you move the mouse over the banner of a photo, its title will be displayed. In our case, each photo has a title corresponding to the name of the photo, and also its azimuth. Arrows will correspond to the azimuth.
You will want to review the Help on Photo Layers for complete detail on creating these text layers. Once created, you can use them to recall your ground truth experience.