Editing Maps in SPRING

This page presents the procedures used for editing thematic, cadastral, networks and DTM (Digital Terrain Model) maps through manual digitization.

The data input for map generation in SPRING can be executed through two different processes: importing or digitizing the data. Importing data can be performed through two formats DXF, DWG, ArcInfo, ArcView, ASCII and the GIS software (GeoGraphic Information System). The digitizing is performed using digitizing tables or using the mouse, (se more details about this operation at importing data and format types).

Before starting an IL digitization it is first required to create the IL. See how to do it at Creating an IL.

IMPORTANT: The IL which will be edited must be active. Others ILs can be visible besides the active IL. An example would be to edit a thematic IL using as a background a satellite image.

NOTE: To digitize using a digitizing table, some system parameters must be configured, before starting the digitization process in the SPRING module (for more information see Installing and Setting up)

To start the digitization using the table it is mandatory to make the table calibration. Once this procedure is done its parameters will be stored in the system, even after the SPRING is terminated, so the calibration can be used to work on a digitization again without requiring a new calibration. In case the map position on the table is changed or substituted by a different one, then the calibration has to be performed again.

NOTE: if the table was not used for a couple of days, even if the map position has not changed, it is recommended a new calibration, because small deformations might occur with the map or with the tape fixing the map.

See also:
Digitalization of Maps


Vector Graphic Editing

When opening an editing interface for any IL of the thematic, numeric or cadastral mode the user has initially the option for Graphic Editing or Checking:

    * in Graphic Editing there exists all the tools required to start the task of lines and points editing;
    * in Verification it is possible to get the data or change lines, points, polygons, nodes and objects attributes.


Vector Editing Parameters

For Graphic editing some parameters have to be observed to get the desired tracing:

  1. Option : Graphic Editing or Checking;
  2. Edit : Lines, Points, Break Lines or Output Contour Lines;
  3. Mode : Continuous or Step;
  4. Topology : Automatic or Manual;
  5. Digitizing Factor (mm) : 0, 0.1, 0.15, 0.25, 0.5, 1.0 or 2.0;
  6. Editing operation : Create Line, Create Closed Line, Create Circle, Create Rectangle, Add Point, Move Point, Move Arc, Move Area, Break Line, Joint Line, Remove Line, Remove Point, Clean Area, Concatenate Lines, Change Orientation or Concatenate Area


The effects of some options presented above are presented below:


Editing Entities

Lines editing is available for ILs of the Thematic, numeric (Contour Lines), cadastral or networks models. Points for the thematic, numeric (spot heights), cadastral or networks models. Break Lines and Output Contour Lines only for ILs of the numeric model.

NOTE: the line editing (Contour Lines) in the numeric model does not use the Topological parameters, but it needs to have informed the height value (Z) for the contour line

Seta_up.gif - 170 Bytes Map Editing


Edit Mode

Continuous Mode

The digitizing is performed based on a Digitizing Factor defined in millimeters. The points are obtained as the mouse is being moved. Click the mouse LF (left button) or the table's Button 1, keep it pressed and drag. To finish the process click the mouse RB (right button) or the table's Button 2.

In case the user forgets to end an arc before starting a new one, a line will connect the last point of the first arc with the starting point of the second arc. So only one arc will be seen in the window.

digit_01.gif - 1094,0 K Arc example using equal spacing between points.


Many times, when digitizing straight lines, it is desired to get less points then when digitizing curved lines, thus just release the LB or Button 1 up to the point where the user wants to continue the same arc.

NOTE:If the mouse is moved fasted than the system ability to acquire points, less points will be sampled, thus, make some moving tests in order to have a better control of the acquiring process for an arc.



Step Mode

In this editing mode, the arc points are acquired with a defined spacing by the user, based on each click on the mouse LB or the table's Button 1. To end the arc click on the mouse RB (right button) or the table's Button 2.

digit_02.gif - 1109,0 K Spacing defined after each mouse click.

In case the user forgets to terminate an arc before starting a new one, a line, connecting the last point of the first arc with the first point of the second arc. In this case only a single arc will be presented.


Seta_up.gif - 170 Bytes Map Editing


Topological Parameters

Automatic Topology

The automatic topology editing has an effect only over the arc (line) being digitized, that is, the nodes and crossing adjust will be automatically recognized when the line is terminated.

When starting an arc, if the distance of its first point (node) to another arc is smaller than the Digitizing factor selected, it will be automatically adjusted.

digit_03.gif - 1013,0 K


In the figure above, after starting the Arc 2, the first node has a distance smaller than the Arc 1 node, making the junction of them automatically. In case this distance is smaller than to any segment from another arc, a point will be inserted and automatically breaks this other arc into two.

In the figure below, when starting or terminating Arc 2, one of its nodes was crossing Arc 1. Besides the fact that the system recognizes the crossing and insert a point, Arc 1 is broken into two (Arc 1 and Arc 3). The Arc 2 segment trespassing Arc 1 is automatically removed, because it was smaller then the selected Digitizing Factor.

digit_04.gif - 14,0 K


NOTE: The break line tool has a different effect when the automatic topology is used. See below in Break Lines.


Manual Topology

When editing with manual topology, the arc being edited surroundings will not be analyzed with other existing arcs. In case an arc starts or ends with a node closer to any other, adjusts will not be performed, thus, the adjusts should be done manually, defining the precision in millimeters. (see the Nodes Adjust topic below). In case this precision is not enough to joint these nodes, a manual line joint has to be performed by the user (see more at Jointing Lines).

Many times the user wants that at the crossing between two lines these lines are broken apart, becoming four lines. However, if the editing was performed using the manual mode topology, these lines have to be broken later on. See more about it at Break Lines.


NOTE: Digitizing using either the automatic or the manual Topology mode can be executed in either the Step Mode or Continuous Mode, that is, these options are independent.

Seta_up.gif - 170 Bytes Map Editing


Digitization Factor (mm)

The digitizing factor corresponds to the distance between the acquired points when digitizing in the Continuous Mode. The given value - 0, 0.1, 0.15, 0.25, 0.5, 1.0 or 2.0 mm - depends directly on the IL scale being edited. For instance: when creating an IL in the 1:100.000 scale and using a digitizing factor with 2 mm, means that the terrain sample will happen at every 200 meters.

In practice this factor value has to be smaller than the cartoGraphic precision limit, acceptable for the map scale, defined with 0.3 mm times the map scale. Thus, for the example above the 200 m sampling is larger than 0.3mm * 100000 = 30000 mm or 30 meters.


NOTE 1: A digitizing factor of 0.0 mm means that the precision being used in the sampling is the one given by the digitizing table, which is usually around 0.04 mm, depending on the table's model.

NOTE 2: In the break line operation, it is suggested to increase this factor, because it is used to the localization of lines which will be broken, and using the 0.0 factor requires to precisely click on the line to be broken, so the operation will be performed.


Seta_up.gif - 170 Bytes Map Editing


See the procedures to ILs editing. Maps thematic and cadastral will be presented together, because the editing is the same for both data types, differing only at the entities association (classes for thematic maps and objects for cadastral maps. Later, the map editing for networks and DTM will be presented.


See also:
How to calibrate a digitizing table
Digitizing Maps

Vector Editing