Reading the dgn format is a norm in most GIS / CAD programs, but several of these (including Manifold GIS and gvSIG) have been reading the V7 format. AutoCAD and ArcGIS have already achieved it.
Let's see how it does it Global Mapper:
1 Lee dgn V8
Interestingly, the files can be in a .tar, .zip or .tgz extension.
Once selected, the program asks what projection will be assigned to them. These can be chosen from a broad list, or from a .prg file, or a .txt containing it. (Does not recognize the internal projection assigned by Microstation Geographics)
Then you can define that you assign the same projection to all the 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.
Texts come as point objects, so they have that point in the lower left node. You can not edit the objects, you can touch and delete or edit vertices, but 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 put 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 to call 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 case of the labels of shapes, they become texts to 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 to export on matrix, very good for too large files. This makes separate files go, and among the best, allows you 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.