Как значительно улучшить качество растров с помощью Easy Trace
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edition of 14.02.05
Simultaneous digitization for GIS and printing

Some parts of polygon boundaries in maps are often represented by dot or dashed lines. These may be borders of vegetation areas, waysides of country roads, and other boundaries between adjoining polygonal objects. How to vectorize a polygon if a PART of its contour should be depicted with points or hachures at printing?
Polygon in a GIS is an areal object. Accuracy of its area, belonging to a certain layer, its attributes and representation (color, filling) are significant whereas boundary presentation is determined by cartographical standards rather than demands of the GIS and thus no way is provided for different line type use when drawing a line.
Nevertheless, there is a simple way out, just a kind of trick:

 
Digitization of polygon boundaries to the Cosmetic layer
 

1. Add a new vector layer for SEGMENTS of polygon borders (let us call it Cosmetic).

2. Create a database table for this layer containing one user-specified field that may be called LINETYPE.

3. Specify possible values of this field: Solid, Dashed, Dot, etc.

4. Adjust line representation on the Cosmetic layer in accordance with the attribute value.

5. Forget about polygonal layers for a while and just digitize boundaries to the Cosmetic layer and input attributes that correspond to linetypes (it is easier to do with the help of the Group Editor for a number of selected lines at once).

6. Form polygons out of the lines (segments). To do it, take a Tracer, and:

  • switch on the Line Vertices view mode ;
  • select manual tracing mode (pulled position of the button);
  • switch on the Autoclose option ;
  • now just click pairs of neighboring points on the borders of future polygons - the tracer will do everything else automatically.

After export to your GIS, make polygon boundaries invisible and adjust representation of layers of the Cosmetic layer as it is in Easy Trace.

An experienced and accurate operator may form polygons out of line segments on the Cosmetic layer IN AUTOMATIC MODE . To do it, apply the Utilities->Topology->Create Polygons command...

Digitization of elevation marks and their inscriptions
 

In a number of large projects we faced an annoying complication. Operators had to input the same text two times - as an attribute of an elevation mark and as a text inscription near it. There were thousands of such marks and we could not permit ourselves to waste time. Besides the double input, attributes need to be checked. We decided to combine the tasks:

Step I. Input of elevation marks and their attributes.

  • Zoom in the image to be able to read elevation values easily.
  • Open View->Magnifier window and set the scale 4:1 (we shall use the window to aim at the center of the mark).
  • Input the first mark. If the program didn't open the Object Attributes dialog box automatically, select the mark with the Editor and use the submenu command to open it.
  • In the Attributes dialog box, switch on the options "Always show this dialog box at object creating" and "Sort". for the field of elevation values.
  • Input the value. (In future try to select a suitable previously used value from the drop-down list and correct 1 or 2 last figures in it).
  • Repeat the operation for all elevation marks in your project.
Step 2. Generation of inscriptions.
  • Utilities->Database->Generate Inscriptions.
    Specify the layer of points - elevation marks, database field (fields) to take text from and text height of course.
  • And here is a ruse - call the layer of inscriptions _ERRORS_ (just so - capital letters and dashes in front and at the end).
  • If you make a mistake at specifying of generation parameters, use the UNDO command and repeat the operation.
  • Select canary color for the _ERRORS_ layer.
Step 3. Chek-up of attribute values and inscription positions.
  • IMPORTANT! The Editor provides automatic navigation between objects on the _ERRORS_ layer. Use hot keys for this purpose F (next mark) and V (previous mark).
  • Select the Editor in the Tools bar, and press F to go to the first mark (elevation inscription).
  • Correct position of the inscription with the Editor if necessary and maybe also ATTRIBUTE VALUE and INSCRIPTION. Remember that text inscriptions and attribute values in the database ARE NOT CONNECTED - you should correct BOTH objects!
  • Press F again to jump to the next mark, and so on.
Step 4. Completion of the operation.
  • Use the Select object by a query command of the Group Editor to select all text objects on the _ERRORS_ layer (i.e. elevation inscriptions) and attribute them to their correct layer.
  • If you continue vectorizing, it is reasonable to make the layer (s) of marks and inscriptions invisible for a while.
  • At last, users of ET 7.95 and later have an opportunity to control automatically elevation values attributed to contour lines with the help of elevation marks - see Utilities-> Z Check-up .

Another version of the algorithm - for those who are not too lazy to change the Editor for the Point tool often. You may activate the "Generate Inscription" option in the Object Attributes dialog box. The program will generate the text just after input of the attribute value and you may check and correct its position at once. Steps 2 and 3 become unnecessary...

The same approaches to generation of inscriptions may be used at input of building outlines. At that, most of the inscriptions will be inscribed in them and aligned along the longest side.

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