Knowledge Base

KB10462 - TatukGIS support for the DXF format.

  • The CAD dxf and dgn formats embed the vector style and label information into the vectors (map geometry), whereas the GIS philosophy is to store vector style and label information in database attribute fields that are associated with the vectors, but not embedded in the vectors. The GIS philosophy offers greater opportunities for data interoperability. TatukGIS products are consistent with the GIS philosophy.
  • When TatukGIS software is used to open a dxf (or dgn) file, the software automatically creates attribute fields to hold vector style and label information.
  • When either dxf or dgn files are saved with TatukGIS software, the color/style information (even if rendered when the file is open) is not saved in the default dxf or dgn manor - because TatukGIS products follow OpenGIS guidelines relating to vector formats, not CAD methodology.
  • To prepare a dxf or dgn file with the DK in such a way that the colors and style rendering are retained after saving the file, first prepare associated database attribute fields to hold the style information to be associated with the vectors. If the DK does not automatically set up an attribute to hold a particular aspect of the style, manually set up an attribute field to hold that information.
  • When creating dxf or dgn files for mapping purposes, strive to logically organize the data into different layers. For instance, one layer might contain roads and streets, another layer might contain streams and rivers, another layer parks, another lakes, etc. Then attributes that are common to all vectors in a layer can be set up for the entire layer, in one step, making the process relatively simple.
  • If vector data representing all different types of information is mixed in a single dxf or dgn layer, this can be a mess. Because the CAD formats do not reflect OpenGIS standards, which require the storage of attribute information to associated, but separated, attribute files, sometimes this is the reality with dxf and dgn files. The only solution in such a situation is to manually separate the data into layers in a logical way, and then assign attributes to each vector class in each layer. This can be a lot of work.
  • After the attribute fields are established with use of the DK, rendering styles (style sheets) must be assigned to the relevant attributes, using the values or text information contained by the attributes, using ini files. For instance, 1 = red, 2 = blue, or red <= 5, blue <= 10, yellow <= 15, etc.
  • Although the styles can be assigned using Notepad within the DK project configuration files, it can be much easier to use the desktop TatukGIS Viewer (a free product) or Editor to do this.
  • The TatukGIS Viewer displays the attribute fields of any selected vector. Then it is possible to select the attribute of interest, and use the Properties function to set a style rule based on the value or text information held by this attribute. The rule will be applied to all vectors in the selected layer. As noted above, if interested in color, then perhaps 1 = red, 2 = blue, or red <= 5, blue <= 10, yellow <= 15, etc. Some style settings, such as transparency factor, can be set to the entire layer. The Viewer can be used to set much more than just color, such as line widths, label colors, polygon fills, polygon perimeters, outlines, label appearances, label positions, fonts, transparency levels, symbols, etc.
  • Refer to the Viewer/Editor tutorials and helpful for guidance.
Created: August 25, 2004, Modified: July 30, 2015
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