Reading the dgn format is a standard in most GIS / CAD programs, but several of these (including Manifold GIS and gvSIG) have been left reading the V7 format. AutoCAD and ArcGIS have already done this.
Let's see how it does it Global Mapper:
1.Read dgn V8
Interestingly, the files can be in a .tar, .zip or .tgz extension.
Once selected, the program asks which projection they will be assigned. These can be chosen from a wide list, or from a .prg file, or a .txt file that contains it. (It does not recognize the internal projection assigned by Microstation Geographics)
Then you can define to assign the same projection to all selected files. You can also generate a projection to taste and save as .prj to call it at any time. It is also interesting that when reopening a file without projection, it stores the last one assigned ... Ohhh yes manifold Look at these simple features !!!
In recent versions, it reads V8, surpassing programs such as Manifold GIS and gvSIG, with the demand that exists for this format and there being only these two among those generated by Microstation.
The texts come as point objects, that is why they have that point in the lower left node. You cannot edit objects, you can touch and delete or edit vertices, but it is only at the view level.
An annoying aspect of the import is that if the objects are white and the background is the same color, it will appear that they do not exist. To do this, you have to place a background of an unusual color, this is done with "view> backgroud color ..."
2. Export to dgn
The export is not bad, it will send what is visible in the catalog of the "control center", which is a way of calling the organization of views. Everything will go in the same projection.
Among the most annoying, the size of the texts. To do this, ask to select a size and you have to try. In the case of shape labels, they are converted into texts at the visible size.
Generates a dgn 3D if the map has elevation data; And then leave the option so that the white objects can be seen black or vice versa according to the background.
It also allows exporting in matrix, very good for files that are too large. This makes separate files go, and among the best, it allows to send the reference grid, which may well be in geographic coordinates (latitude / longitude) or UTM.
The export will have problems with complex objects, as in the case of shapes that have holes, since Microstation up to the V8.5 versions still manages these elements as complex shains or cells.
3. Extra options
It is worth mentioning that among the extra configurations you can define that when importing cells (cells, or blocks) into points; If not, exploit them as vectors.
It is also possible to define that the color number can be assigned as an attribute in the table, which would allow the thematization of this criterion.
In conclusion, moderately acceptable. Even though Global Mapper Does many things more.