Digitalization of Maps

This page presents the procedures for vector edition of the "Topological Edition" window. Thus, the same window is used to edit a Thematic, Cadastral, Network or Numerical IL, diverging only in some small details.

Basically the user is capable of:

  • Editing in an active IL - option Graphical Edition or
  • Verifying something already edited - option Verify

See first the editing tools for each data model:

NOTE: Thematic and cadastral maps will be presented together, because editing them is basically the same operation, with a small difference in the entities association (classes for thematic maps and objects for cadastral maps). Later, it will be presented how to edit networks and DTM maps.

See about Digitalization using the SPRING

See also:

The SPRING Conceptual Model
About Vector Edition
Digitizer calibration
About the vector element ASCII-SPRING format


Thematic/Cadastral Maps

A thematic or cadastral map has regions geographically defined by entities: points, lines and polygons. The Digitalization process in both cases is the same, the only difference is in the application of each entity.

Thematic Maps

A thematic map usually has qualitative information about a unique theme, such as, vegetation classes, soil etc. These data are obtained from field measures and later added in the system either using Digitalization or from automatic image classification.

A thematic map has to be associated to a thematic model category, where the spatial modeling process is defined by geo-fields, represented by homogeneous delimited areas (polygons), polygonal lines or points. Each Geo-field is associated to a single spatial variable value, that is, in a soil map, each point in the map is associated to a specific soil type (e.g.Dusk Red Latosol).

Cadastral Maps

A cadastral map helps getting information such as urban cadastral data, rural cadastral data etc. This map has to be associated to a cadastral model category, where the spatial model process is defined by geographical objects. The difference for a thematic map is related to the fact that it does not have themes and consider its elements as geographical objects with attributes, and can be represented in several maps using different scales or projections. For instance, the lots in a city are elements in the geographical space with several attributes (owner, address, tax etc.) and they can be represented in several maps each using a different scale.

In the cadastral map, the objects are usually defined a priori and its geographical location can be done a posteriori. For example, it is possible to mention the objects "São José dos Campos Schools", and, more specifically, the "XXY High Scholl". Such objects exist independently of their map representation; they are usually created from their attributes and they will be located in space only in the next step.

Another example is the object class hospital in a cadastral map, which can be a public or private hospital. The hospital class attributes are inherited by the sub-classes public hospital and private hospital, which might have their own attributes.

Notes about thematic and cadastral maps:

A thematic map can be stored in the vector or raster form (all entities are divided into cells of a fixed size, and each cell has a corresponding value related to the most frequent theme in that spatial location). However, in a cadastral map we have only a vector representation.

A topological representation for thematic or cadastral maps, in the vector format has the type edge-node-region. Edges are connected among them through nodes (starting and ending points) so they make polygons (regions), or the edges only represent polygonal lines and the points only geographical features which can not be represented in their dimension.

Digitalization


Line Digitalization

The line Digitalization happens when the user wants to have an IL with vector elements in the form of lines and/or polygons. If the lines don't define a polygon, it is neither required the polygonalization nor the automatic adjustment, if the lines extremes are not connected.
The figure below presents some lines that don't define a polygon and other lines that define two polygons. The lines not defining a polygon (at left) represent a river network, but Note that the L1 line is not necessarily segmented at the extremity of line L3. The crossing of these two lines is only visual. However, the right part of the figure presents two polygons and the line L2 is common to both polygons. To build this figure at right (the polygons) it is required to edit the lines, adjust the extremities and make the polygons. But the lines at left don't require any adjustment or polygonalization.

See next the procedure for editing a thematic or cadastral map.

Lines Digitalization in a Thematic or Cadastral Map:

  • load the Database and the desired Project;
  • create an Information Layer, from the thematic or cadastral model, as presented at Creating an IL. Remember that the IL scale has to be the same as the map scale (disregard this step if the IL was previously created);
  • click on Tools - Digitizer Calibration.. (only if the Digitalization process is using a table);
  • activate in the "Control Panel" the Information Layer which will be edited. Other ILs can be visible (for instance, an image as a wallpaper), but it is important to pay attention to see which IL is active before starting the edition;
  • click on Thematic - Vector Editing... or Cadastral - Vector Editing... in the main menu, according to the active IL model. It is also possible to use Edit - Vector... for editing any active IL;
  • select Graphical Editor;
  • on the Edit:, select Lines;
  • on Mode:, select Step or Continuous;
  • click on the Digit. Step (mm) down arrow and select a value (remember that the value is a function of the IL scale);
  • on Topology:, select Automatic or Manual ;
  • on Operation:, select one of the following: Create Line, Create Closed Line, Create Circle, Create Rectangle etc. as desired;
  • if you are using a Digitizer Calibration, click on View - Digitizer Cursor or click on the icon   in the main menu. At this moment only the digitizing table cursor will be enabled;
  • start the Digitalization with the mouse LB (left button) or the table's Button 1;
    • when using the continuous edition mode, click and drag the mouse left button to define a trace. Remember that the spacing between points will depend on the Digitalization factor.
    • when using the step edition mode just click on each line vertex.
  • click on the mouse RB (right button) or on the table's Button 2 to close an arc or an island;
  • click on Button 4 in the table's cursor to return the commands to the mouse (only if using a digitizing table).

NOTE 1: During a line edition (arc), small circles (red) are presented around each point in the line. The size of these circles depends on the value selected for the Digitalization factor. For a line previously defined it is also possible to see the line points by holding the RB - right button - on the line.

NOTE 2: During the line edition, the green color is used as "default" in the continuous mode and the red color is used in the step mode. When the line is closed the color turns to red.

See next the procedure to change or fix lines in a thematic or cadastral map.

Fixing Lines in a Thematic or Cadastral Map:

  • activate the Information Layer to be edited in the "Control Panel";
  • click on Thematic - Vector Edit... or Cadastral - Vector Edit... in the main menu, depending on the active IL model. It is also possible to use Edit - Vector... for editing any active IL;
  • select Graphical Editor;
  • if youcheck the Contour box, the limits of the IL being edited will be displayed. This shows the usable limits of the IL. It is not possible to edit beyond this limit;
  • if you check the Adjusted Nodes box the line starting and ending points which are connected to other lines will be displayed using circles and the green color. If you check the Not Adjusted Nodes box the lines starting and ending points which are not connected to other lines will be displayed using stars and the blue color. Choose the Digit.Step(mm) value using the down arrow to change the size of the nodes;
  • click on the Edit down arrow and select Lines;
  • select the desired operation: Add Point, Move Point, Move Line, Move Area, Break Line, Join Lines, Delete Line, Delete Point, Delete Area, Concatenate Lines or Concatenate Area


Digitalization of maps


Saving Lines

The edited lines are presented using the red color. In order to store the changes in the vector structure in the SPRING system it is required to click the "Save" button. The lines will change their color to the color defined in the visualization of the active IL.

NOTE: Once the changes are saved it is not possible to "Undo" the operation;

 

Points Digitalization

Editing thematic and cadastral points is useful for features representation or for objects that can not be represented by polygons. In the same way as lines, points can be edited using a digitizer table or a mouse. Remember that, in order to use a digitizer table it is first required to calibrate it.

The figure below shows two points with different symbolism, one thematic ( left) and another cadastral ( right). In the thematic case, it is only required that the point exists in order to associate it with a class previously defined. However, if the point is cadastral it is required to select an existing object and associate it using a label and a name defined by the user. Details about the association with objects or classes can be found here.

Digitizing Points in Thematic or Cadastral Maps:

  • activate the Information Layer with the data points to be digitized in the "Control Panel";
  • click on Thematic - Vector Edit... or Cadastral - Vector Edit... in the main menu, depending on the active IL model. It is also possible to use Edit - Vector... for editing any active IL;
  • select Graphical Editor;
  • on Edit:, select Points
  • on Operation:, Create
  • when using a digitizer table click on View - Digitizer Cursor or in the main menu. At this point only the digitizer cursor will be active;
  • start the Digitalization; each click with the mouse LB (left button) or the digitizer's Button 1 adds a new point;
  • click on the table's Button 4 to return the commands to the mouse (only when using the digitizer table).

Removing Points in Thematic or Cadastral Maps:

  • select the Erase option in the down arrow in the Operation box to remove points
  • when using a digitizer table click on View - Digitizer Cursor or atalho_cursor_mesa.gif - 1030 Bytesin the main menu. At this point only the digitizer cursor will be active;
  • click with the mouse LB (left button) or the digitizer's Button 1 over a point;
  • click on the digitizer's Button 4 to return the commands to the mouse (only when using the digitizer).

Moving Points in Thematic or Cadastral Maps:

  • select the Move option at the Operation box using the down arrow;
  • when using the digitizer click on View - Digitizer Cursor or in the atalho_cursor_mesa.gif - 1030 Bytesin the main menu. At this point only the digitizer cursor will be active;
  • click on the point using the mouse LB (left button) or the digitizer's Button 1 and drag it to the desired position;
  • click on the digitizer's Button 4 to return the commands to the mouse (only when using the digitizer).

Saving Points

As when dealing with lines, points will exist in the SPRING vector structure after clicking on the "Save" button. Once the points are saved it is not possible to Undo operation.

NOTE: The edited points are displayed as red circles, after saving them, they are displayed using the color and style defined in the IL visualization depending on the category they belong.

The IL Visual Aspects

During the geographical entities Digitalization in a map, it is possible to change the visual aspects of lines and points being edited.

Changing the visual aspects of lines and points in the active IL:

  • click on Visual... to show the Setting Visual Parameters window. Change the line parameters (thickness, color etc.) (for more details see Visual...);
  • click on Apply at this window so the changes will take effect;
  • click on Execute - Draw or atalho_desenhar.gif - 941 Bytesin the active window to see the changes.

NOTE: The procedure to change the visual aspects can also be obtained at Edit - Information Layer in the menu, or using the atalho_pi.gif - 949 Bytesicon, selecting the appropriate entity and clicking on Visual....

Digitalization of maps


Adjusting Nodes

Adjusting the nodes will guarantee that they will be placed at the ending points of lines. The algorithm uses a precision defined by the user, which corresponds to a distance value centered at each node. If there is another node inside the square area defined by the precision, they will be adjusted into a single node. This procedure is valid for all nodes.

The higher the precision, the smaller the error possibilities and the smaller the possibility to mix up neighbor nodes. The user should use the highest precision and, if required, adjust other points using the manual adjustment procedure ( Join Lines) using the Edit Button Line Edition option.

Depending on the precision being used, some nodes, at the line ending points, may disappear, because there will be only one node inside the square area defined by the precision. The figure below shows what happens with the nodes at the ending points of a line.

digit_10.GIF - 2937,0 K

The figure below shows four lines (1 through 4) when, after executing the adjustment procedure using a certain precision value, one can observe that the adjustment procedure was not enough to adjust the node in line 3. The "A" node, after the adjustment procedure, has only the lines 1, 2 and 4. If possible and desirable one can try a new node adjustment using a smaller precision.

digit_11.GIF - 3852,0 K

ATTENTION: Be careful when making adjustments with smaller precision values, because some connections might change the line pattern. For instance, in the figure above, the union of line 3 with the others might not be desirable.

Another example (figure below) shows a common error performed by the user while digitizing several islands, for instance: a cadastral map showing urban lots. Note what might happens when using a small precision during the node adjustment. When closing two or more islands, their shape might change.

digit_11a.gif - 3721 Bytes

During the lines edition step, or lines correction for closing polygons, the user might click on the Adjusted Nodes or Not Adjusted Nodes button in the "Topology Editor" toolbar. After activating this option click on Execute - Draw or click on the atalho_desenhar.gif - 941 Bytes  in the active window which shows the edited lines. At the lines ending points (nodes) a cross (X) will be displayed using the blue color if the line is not connected to another line, and a green square when the node is connecting at least two lines.

NOTE: There is also the option to display the active IL Contour; just check the Contour button at the "Topology Editor" toolbar.

Digitalization of maps


Generating Polygons

Once all nodes were adjusted, the final topology must be defined through the polygonalization procedure. The lines, which were considered as single structures so far, will be considered as part of polygons, with a neighborhood relationship among them.

The polygonalization option assumes that the nodes were previously adjusted so, later on, a polygon identification can be performed with either as thematic classes or as cadastral objects.

ATTENTION: It only makes sense to generate polygons when the map has entities of the polygon type.

Adjusting and generating polygons in a thematic or cadastral maps:

  • select a Snap (mm) value among 0, 0.1, 0.15, 0.25, 0.5, 1.0 or 2.0; for adjustment nodes with the digitized data;
  • click on Adjust. A message at the bottom of the window will display the number of nodes adjusted, and also if there is a node with a single connection, which might be an error; otherwise the "All lines were adjusted" message will be displayed.
  • check in the window to see if there are lines that are not adjusted; click on the Show nodes button to make it easier. If necessary adjust the data again with a small precision or make the manual adjust ( Connecting Lines option);
  • click on Generating Polygons to generate the polygons. A message will be displayed at the bottom of the window with the number of polygons generated.

Digitalization of maps

Entity Identification (labeling)

After defining the polygons they can be associated to thematic classes, previously defined in the Database, or they can be associated to cadastral objects. See how to proceed in both cases.

Digitalization of maps


Network Map

This is a map that uses the arc-node topology and that stores the location and the symbolization which is associated to structures linearly connected. The networks graphical information are stored using only vector coordinates. A network map can be associated to information of the following types:

  • Public utility services, water, electricity and telephone;
  • Drainage Networks (hydrographical bays);
  • Highways.

This map allows to generate a continuous cartographic base from information distributed in several maps. The networks (electrical, telephone, water, sewerage etc) are interconnected in a grid system, so that it is possible to make analysis and data simulations.

This map must be associated to the network model category, similarly to the cadastral model, where the spatial modeling process is defined by geographical objects. Each geographical object in the network map (e.g. telephone cables, water tubes, electrical network transformer) has an exact geographical location and it is always associated to descriptive attributes stored in the Database.

The arc attributes indicate the flow direction while the node attributes indicate the impedance (path cost). The network topology forms a graph which stores information about resources that flow among distinct geographical locations. The topology is created automatically, that is, during the lines crossing, the nodes are created automatically, thus the node adjust operation is not required. Example given, consider an electrical network which has the following components: poles, transformers, substations, transmission lines and keys. The transition lines are represented topologically as arcs in an oriented graph, all other information are stored in the node.

The figure below shows a small part of a city streets network, Note that each segment is connected to a node (green circle). It will be seen that one can associate objects either to network segment or to nodes.

The editing tools such as Mode ( Continuous or Step), Topology ( Manual or Automatic), Digitalization factor and all other options for editing points and lines, are the same as described in the thematic or cadastral maps.

Network Maps - Lines Digitalization:

  • load the desired Database and Project;
  • create an Information Layer, from the network model, as described in the Create IL. Remember that the IL scale has to be the same as the map scale (if the IL was created previously do not consider this step);
  • click on Tools - Digitizer Calibration.., in case this operation was not performed previously for the map being used (see digitizer calibration);
  • activate the "Control Panel" in the Information Layer which has the data to be digitized;
  • click on Network - Editing... or Edit - Vector... in the main menu;
  • click on Graphical Editor;
  • click on the options button Edit and select Lines;
  • click on the options button Mode and select between Step or Continuous;
  • click on the options button Digit. Factor(mm) and select a value (remember that the value is a function of the scale used in the IL);
  • click on the Topology button and select between Automatic or Manual ;
  • click on Create Line (for an arc) or Create Closed Line, Create Circle or Create Rectangle (for an island) as desired;
  • if one is using a table click on View - Digitizer Cursor or atalho_cursor_mesa.gif - 1030 Bytesin the main menu. At this moment only the digitizer cursor will be available;
  • start the Digitalization using the mouse LB (left button) or the table Button 1;
  • click on the mouse RB (right button) or the digitizer's Button 2 to finish an edge or an island;
  • click on the digitizer's Button 4 to return the commands to the mouse (only if using the digitizer).

Note 1: During a line editing (arc), small circles (red) will be displayed around each point in the line. The size of these circles depends on the value selected for the Digital Step. For a line previously created it is also possible to see its points, just clicking on it using the mouse RB.

Note 2: During the line editing as "default", the green color (for the continuous mode) and red color (for the step mode) will be used until the end of the editing process, then the line will turn red.

Note 3: Note that the Gener. Polygons button will be disabled while working with a network maps. Only the Adjust will be available for the IL.

Next, see the procedure to change or fix a line in a network map.

Fixing Lines in a Network Map:

  • activate in the "Control Panel" the Information Layer to be edited;
  • click on Network - Edit... in the main menu. One can also use the Edit - Vector... to edit an active IL;
  • click on Graphical Editor;
  • if desired check the Contour box to show the IL editing limits. This will display the area in the IL that can be edited. It is not allowed to edit beyond these limits;
  • check the Adjusted Nodes and/or the Not Adjusted Nodes to display the starting and ending points of the lines. The adjusted nodes will be displayed using the green color and the not adjusted nodes will be displayed using the blue color. Use the Digit. Step(mm) to zoom in or out these points;
  • In the Edit operation select the option Lines using the down arrow;
  • select using the down arrow, in the Operation box, one of the following options: Add Point, Move Point, Move Line, Move Area, Break Line, Join Lines, Delete Line, Delete Point, Delete Area, Change Orientation, Concatenate Lines or Concatenate Area

Saving lines

All edited lines will be displayed using the red color. In order to store them and their changes in the SPRING vector structure one needs to click on the "Save" button. Then, the lines will be displayed using the color defined in the IL visualization aspects.

Note 1: After saving the lines it is not possible to use the "Undo" operation;

In order to have a complete network map after importing lines or digitizing them, one has to:

Adding turn restrictions

  • Select the operation Add Restriction;
  • Click with the left button on the source arc, ie. the arc that is the flow source;
  • If you want to cancel the operatio, do a right click;
  • Click with the left button on the target arc, ie. the arc with a flow barrier.

Removing turn restrictions

  • Select the operation Remove Restriction;
  • Left click on the source arc, ie. that arc that is the flow source;
  • If there is a single restriction on the target arc, the restricion will be removed;
  • If not, you have to select the target arc too, using the left mouse button. It is possible to cancel the operation with a right click.

Digitalization of maps


DTM

The digital terrain model is a mathematical representation for the spatial distribution of a certain characteristic attached to a real surface. In order to get this representation it is required to perform a line and points Digitalization, which will make the samples so, later on, it will be possible to generate interpolations (grids) and get products, such as 3D visualizations, profile etc.

During the lines Digitalization the cursor follows the contours, opened or closed, defined in the map. The user associates a value for the z coordinate (height) to a line.

Another line type that can be digitalized are the break lines. The break lines are used for triangular grid generation by quantum interpolation. These lines can be referred to surface discontinuities, represented by valleys alignment or ridges. For instance, a river can be edited as a break line where through the shore lines there is a relief discontinuity without a height value associated to it. These break lines can be considered or not during the triangular grid generation. See more information about the break lines and triangular grids.

During the points Digitalization the digitizer cursor is manually applied to the point, and its coordinates (x, y) are registered. The user associates a value for the z coordinate (height) to the point.

A DTM map has to be associated to a numerical model category, where the spatial modeling process is defined by geo-fields, thus, considering a certain geographical area, a numerical Geo-field associates, to each point in space, a real value.

A DTM map can be stored either using the vector format (when there is a representation referred to the samples or triangular grid) or raster format (when there is a regular grid).

In the vector representation, the topology can use the arc-node format, where arcs are connected using nodes (starting and ending points) or Triangular Grid (TIN). In this last case, the arcs are connected using points, making a triangular grid.

The raster representation uses a rectangular grid type, that is, an area will be divided into fixed size cells, where each cell will have a value according to the sampled data and the interpolation method used. For more details see DTM data types and interpolation methods.

The figure below shows part of some samples, contour lines plus spot heights. Note that both entities have to be in the same IL in order to consider them for the interpolation process.

Next, see the procedure for numerical map edition.

Sample Digitalization

The editing tools, such as Mode (Continuous or Step), Manual Topology (The Automatic is not used for this kind of data), Digital Step and all Editing options for lines and points, are the same as the ones described for cadastral and thematic maps, one only needs to inform the Z value before starting the Digitalization.

Contour lines Digitalization

Contour lines Digitalization:

  • activate the desired Database and the Project;
  • create an Information Layer of the numerical model. Remember that the IL scale has to be the same as the map scale (if the IL was created previously, do not consider this step);
  • click on Tools - Digitizer Calibration..in case this step was not executed previously for the map fixed on the table (see digitizer calibration);
  • activate in the "Control Panel" the Information Layer that has the data to be digitized;
  • click on Numerical - Vector Edition... or Edit - Vector.. in the main menu;
  • check the Graphical Edition;
  • click the Edit button and select Lines;
  • click the Mode button and select between Step or Continuous;
  • click the Digit. Step(mm) button and select a value (remember that this value is a function of the IL scale);
  • the Topology button is not available. The Manual option should be used in this case;
  • type in the Z Value (the height value of the contour line). Don't forget to click on CR so the system will take the digitized value.
  • click on Master if you want a differentiated visualization for the contour line to be edited. In this case the thickness of the contour line will be increased; CR so the system will take the digitized value.
  • click on Create Lines (for opened contour lines) or Create Closed Lines (for closed contour lines, that is, lines closing and making islands) as desired;
  • if using a digitizer click on View - Digitizer Cursor or atalho_cursor_mesa.gif - 1030 Bytesin the main menu. In this case only the digitizer cursor will be active;
  • start the Digitalization using the mouse LB (left button) or the digitizer Button 1;
  • click the mouse RB (right button) or the digitizer's Button 2 to close an edge or an island;
  • click the digitizer's Button 4 to return the commands control to the mouse (only if using the digitizer).

NOTES:

  • When start the arc or contour line edition, as "default" the green color will be used, at the end of the edition the color will turn into red.
  • In practical terms it is easier to first edit all the contour lines that have the same Z value, before changing to another height. When changing the Z value don't forget to click on CR so the system will recognize the changed value. In order to fix Z values use the Verification operation, described below.
  • During a line (arc) edition, small circles (going from red to cyan colors) following the points orientation making the line. The size of the circles are related to the digit. step value selected before. For a line created previously it is also possible to visualize these points, just clicking on the line using the mouse RB (right button).

HINT: For numerical models (contour lines) samples, it might be useful that each contour line is displayed using a different color. This facilitates height errors identification. This resource depends on the IL scale that will generate the color variation and also to turn it on one should change the area visualization aspects to the EMPTY type, from the "Information Layer" window.

Next, see the procedure for changing or fixing lines in a numerical map.

Fixing Lines in a Numerical Map:


Saving Contour lines

The edited lines are presented in the red color. In order to store them in the SPRING vector structure one have to click on the "Save" button. The lines will be displayed using the color defined in the visualization aspects of the IL.

Note 1: After saving the lines it is not possible to use the "Undo" operation.

Digitalization of maps


Break Lines Digitalization

Editing break lines is performed in the same way as contour line edition, the only difference is that there is no Z value for the break lines. Usually these lines are used as mountain ridges or the bottom part of valleys See details about using break lines.


Spot Heights Digitalization

The spot heights should be in the same IL as the lines, so the system can recognize them when using the interpolators. In the same way as the contour lines, the spot heights can be edited using a digitizer or a mouse. If one wants to use a digitizer to enter the points don't forget the digitizer calibration.

Digitizing Spot Heights:

  • activate in the "Control Panel" the Information Layer which has the data to be digitized;
  • click on Numerical - Vector Edition... or Edit - Vector... in the main menu;
  • check the Graphical Editor box;
  • click on Edit box and select Points. Note that the Point Editing buttons become enable;
  • type in the Z Value for the point. You should not forget to click on CR so the system will take the value typed;
  • click on Create in order to add a new point;
  • if using a digitizer, click on View - Digitizer Cursor or atalho_cursor_mesa.gif - 1030 Bytesin the main menu. At this moment on only the digitizer cursor will be enable;
  • start digitizing; each click using the mouse LB (left button) or the digitizer's Button 1 adds one point;
  • click on the digitizer's Button 4 to return the commands control to the mouse (only if using a digitizer).

Deleting Points from a Numerical Map:

  • click on Delete to select the deleting points option;
  • if using a digitizer click on View - Digitizer Cursor or atalho_cursor_mesa.gif - 1030 Bytesin the main menu. At this point only the digitizer cursor will be enable;
  • click using the mouse LB (left button) or the digitizer's Button 1 on a point to delete it;
  • click on the digitizer's Button 4 to return the commands control to the mouse (only if using a digitizer).

Moving Points in a Numerical Map:

  • click on Move to select the moving points option;
  • if using a digitizer click on View - Digitizer Cursor or atalho_cursor_mesa.gif - 1030 Bytesin the main menu. At this point only the digitizer cursor will be enable;
  • click using the mouse LB (left button) or the digitizer's Button 1 on a point and drag it to the desired position;
  • click on the digitizer's Button 4 to return the commands control to the mouse (only if using a digitizer).

Saving Spot Heights

In the same way as lines, points will be stored in the SPRING vector structure once the "Save" button was clicked on. After saving them it is not possible to use the "Undo" operation.

Note: The edited points are presented using red circles, after saving them, they are displayed using the color defined in the IL visualization aspects depending on the category they belong to.


IL Visualization Aspects

During a map digitizing process, the way contour lines and points are presented can be changed. See next how to do it.

Changing Categories Visual Aspects:

  • click on Visual... to show the "Setting Visual Parameters" window. Change parameters such as the line width, color etc. (for more details see the Visual definitions for the category);
  • click on Apply so the changes will take effect;
  • click on Execute - Draw or atalho_desenhar.gif - 941 Bytesin the active window to see the changes.

HINT: For numerical model (contour lines) samples it might be useful to show each contour line using a different color. This helps error identification in the contour line heights. This resource depends on the IL scale for generating a color scale, in order to enable it, one should change the area visualization aspects to the EMPTY type.


Node Adjustment

A node adjustment guarantees that nodes at the end of contour lines will coincide. The algorithm for node adjustment uses a precision defined by the user, which corresponds to a distance value centered in each node. If another node is placed inside the squared area defined by the precision factor, it will be adjusted and the two nodes will become only one. The process is repeated for all nodes.

NOTE: Be careful when defining the precision value so contour lines with different Z values will not get connected. The higher the precision the smaller the possibility for errors and the higher the possibility to not connect all the neighbor nodes. We suggest that the user sets a high precision value, and if there are points not adjusted automatically then perform a manual adjust ( Join Lines) using the line editing option.

During the line editing phase, or possible edge corrections which were not closed into polygons, the user can select Show Nodes option in the "Topology Editor" window. After activating this option click on Execute - Draw or atalho_desenhar.gif - 941 Bytesin the active window which has the edited arcs. At the ending point of each arc (node) a blue star (X) will be displayed when the arc is not connected to another arc, and a green circle will be displayed if there is a connection involving at least two arcs.

NOTES:

  • It is also possible to display the active IL contour, just check the Contour box in the "Topology Editor" window and then click on Execute - Draw or atalho_desenhar.gif - 941 Bytesin the active window.
  • Although the data polygonalization of numerical terrain models is not usual, it can be requested by the user, such as when hydrographical bays analysis are performed and when area and volume of intervals for hypsometric curves are required. In this way the DTM data has to be converted to the thematic category, adjusted, all the polygons have to be generated and later on the thematic class association should be performed.

Verification

This task allows to get information related to the digitized data. Depending on the model of the active IL we have:

  • Information only displayed at the bottom of the window - Thematic and Cadastral ILs;
  • Information displayed in specific windows, where it is possible to change them - Numerical and Network ILs.

For thematic or cadastral IL's the following data can be verified at the bottom of the window:

  • Lines - line number (L), number of points in a line (pts), length (in meters), right polygon (RP), left polygon (LP) and class if it belongs to a thematic IL;
  • Points - point number and point coordinates;
  • Polygons - polygon number (P), number of lines in the polygon (L), number of polygon sons (S) and classes (C) if thematic;
  • Nodes - Node number (Node) and number of lines connected to the node (Lines).
  • Multiple Objects - shows in the window all points/lines/polygons that are attached to more than one object. It can also be used for a network map. This option automatically returns "Lines" after highlighting the objects in the window;
  • Single Lines - shows in the window all the lines that belong to only one polygon. This option automatically returns "Lines" after highlighting the objects in the window.


For numerical and network IL's besides the information displayed at the bottom of the window, other windows are also presented.

Next the procedure for any kind of data verification is presented.

Verifying Data in an Active IL:

  • activate in the "Control Panel" the IL you want to verify;
  • click on Edit - Vector... in the main menu. The "Topology Editor" window is presented. This can be also accomplished by the option Thematic - Vector Editing..., Numerical - Vector Editing..., Cadastral - Vector Editing... or Network - Vector Editing... depending on the active IL model;
  • click on Verification. Note that all other options in the window become disabled;
  • click on the Verify button and select one of the available options;
  • click on the entity inside the window or check the ones which are highlighted. Their values are presented at the bottom of the editing window or in another window (if using the numerical or network IL) for editing the values.

NOTE: In case we are dealing with polygons, when clicking on them in the active window, a green square highlights the polygon with a number, as presented in the figure below.


Other Window Options "Topology Editor"

Update Indexes: This button was created in order to fix some inconsistencies during the digitizing process. It is not known, for sure, but when using the digitizing operations very often in the same section the line indexes file can break in the existing IL. In this case, some lines already created just disappear from the drawing window, although they are stored in the system. Thus, in case this happens, just click on this button, so the system will fix these inconsistencies.


Update Area/Perimeter : Object maps store the area and the perimeter values (for cadastral models) and just the perimeter value (for networks) in the Database. When using some of the digitizing tools (operations), for instance, moving a point from a polygon limiting line, may cause a change in the area and/or perimeter value. In this case the user has two options: it is possible to adjust the line and polygon to fix the area/perimeter value or just click this button. It is only required to adjust lines and generate polygons again for the whole IL if the whole IL topology was changed or broken, or when new polygons were created.

 


See also:

Raster Edition
About Vector Edition
How to calibrate a digitizer
About the ASCII-SPRING format for vector elements

Digitalization of maps

Vector Edition