SMS:Digitize

When digitizing in the map module, elevations are assigned as with other digitization in SMS. That means that when creating a node, point, or vertex, it is assigned the default elevation value for digitization. The default elevation is initialized to 0.0. The default changes any time a new Z-value is specified. Therefore, if creating a map point or node, and specifying an elevation for that selected point, the value specified is now the default value for newly digitized points, nodes and vertices. (Note: when creating mesh nodes, there is an option to ask for an elevation each time a node a node is created, but this option is not available for scatter vertices or map module objects.)

If wanting to digitize aspects of an image (*.tif, *.jpg, ...), simply load the image file into SMS and select the desired tool from the Map module tools (Create Feature Arc, Create Feature Point, etc.) and click over the part of the image to digitize.

Tips for Digitizing

The following are some useful tips for digitizing feature objects:

• Use the Create Feature Arc tool to make arcs. Click once to start an arc. Single click along the arc to create vertices. Double-click to end an arc.
• Nodes indicate the start and end of each arc. Vertices are points where the arc changes direction.
• Clicking on an existing node with the Create Feature Arc tool will start the new arc on the existing node. Nodes can belong to multiple arcs.
• Use the Select Feature Node or Select Feature Vertex to move nodes on an arc that may need adjustment after creating an arc.
• For long arcs, they can be created in using multiple arcs then merging the arcs by deleting the shared nodes where the arcs meet or converting the shared nodes into vertices using the Convert to Vertex command.
• Nodes can be added to existing arcs.
• Points are created separate from any arcs.
• Multiple points, arcs, nodes, or vertices can be selected holding down the SHIFT key while selecting.
• Polygons are not created automatically. The Feature Objects | Build Polygons command must be used to create polygons.
• Multiple arcs can be joined into an arc group. Creating an arc group allows using the Select Feature Arc Group tool to select all the arcs in the group at once and assign the same attributes to all arcs in the group.
• The image transparency can be adjusted to make seeing the feature objects easier.
• Different feature objects may need to be created in different map coverages depending on the intended model. For example, if intending to use the SRH-2D model, the project domains will need to be digitized in the boundary conditions coverage while any obstructions will need to be digitized in the obstructions coverage.
• The processing of digitizing can be sped up by duplicating coverages that already have many of the necessary feature objects then changing the coverage type and editing the feature objects. Duplicating a coverage is done by right-clicking on it in the Project Explorer and selecting the Duplicate command.
• The processing of digitizing can also be sped up by merging coverages by selecting multiple coverages using the Ctrl key then using the Merge Coverages right-click command.
• Currently, SMS does not have an undo feature. If a mistake is made when creating a feature object, the object will need to be either edited using the selection tools or the object will need to be deleted then recreated.

Related Topic

• Map Module Tools