LandXML Import

FieldGenius can import LandXML files. Rather than convert these files into some different format, you can read these files directly into FieldGenius.

Importing a LandXML File

There are several different methods of importing a LandXML file:

By using the Import LandXML File command.
By using the Data Manager | Map Data Layers | Add File command.
By placing a LandXML file into a Project folder. This is normally done by desktop software like MicroSurvey CAD or inCAD. If FieldGenius finds a LandXML file that has the same name as the Project, and it is in the Project folder, then it will automatically be imported when you load the Project.

When a LandXML file is read, it is scanned to make a list of the objects that it contains. Loading the entire file into the FieldGenius Project could use many megabytes of valuable memory. Therefore, when you wish to use data from a LandXML file, you need to load it as needed. Sample LandXML files are available at the LandXML web site: www.landxml.org

One of the example files posted is subdivision-xsec.xml. We have downloaded and are now going to show the results of reading it into FieldGenius:

LandXML Components and How to Use Them

There are many different types of objects in a LandXML file. FieldGenius will be expanding the use of these objects as the program grows.

As of the date this manual was written, the following objects are supported. This list will change, so you may notice other options on the smart menus for these objects.

CgPoints

A LandXML file can contain many different sets of points. The LandXML specification requires that every point in a LandXML file have a different id. For example you cannot have two CgPoint sets containing a point with the same id. Since a LandXML file can contain many different CgPoint sets, and these point sets may contain thousands of points, FieldGenius lists these sets in the Project Manager. When you want to see them on the screen, you need to use the Smart Menu to Load the CgPoint Sets.

By default when you import your LandXML file, the CgPoints will be displayed on the screen. CgPoints are not stored in the database but they can be used by our commands. For example you can use the Occupy Point command and select the CgPoints with the point chooser for the setup and backsight points. You can also consider them to be read only points.

Surfaces

Surfaces can be imported into FieldGenius from a LandXML file. The surfaces can be imported in two ways:

Fast: We can use the points that define the surface and let FieldGenius re-calculate the TIN model. This might be acceptable for an area where no attempt was made to edit the triangles or add break lines. FieldGenius can compute a surface in seconds from large numbers of points.
Maintain Triangulation: we can force FieldGenius to read the TIN exactly as computed by the desktop software. This requires much more computing by the import program, but it will exactly maintain the triangulation in the original surface. For example, if the LandXML surface was created by using breaklines and hand editing, you will want to maintain the exact triangles for staking and viewing the surface.

You can set the import method by going to the Main Menu | Data Manager | Surfaces | Surface Options.

From the Surface Manager you can see a list of the surfaces in the XML file. Select the one you want to load.

Alignments, Profiles, and Cross Sections

Alignments, cross sections, and staking of these items are some of the powerful features in FieldGenius. Almost all modern road design software will export alignments in LandXML format. We read the horizontal alignment (which is normally at elevation zero), the vertical profile, and the cross sections from LandXML files. Individual components can be selected for staking or viewing information. The Project Manager is used for visibility of these items, and you can drill down into the components right to the coordinate level.

Reading the basic alignment information is done when you import the LandXML file. Alignments generally are not too large, so we read the alignment, profile and cross sections into memory for later use. There may be several surfaces in an alignment, so you can view each cross section surface separately. Each may be staked. In this sample file, there are several alignments. Each alignment can be turned on or off, or just the cross sections for an alignment can be turned off.

Following is a tiny excerpt from the first few lines of this LandXML file. Fortunately, it is rarely necessary to open a file; however, if you open one in Internet Explorer, you will see the format. They are easily explored, because you can "collapse" sections of the file by picking on the negative signs at the beginning of the lines in Internet Explorer. In this picture, all of the file has been collapsed except for the header. It is easy to see that the file was created by Autodesk Land Desktop version 3 with Service Pack 1 installed.

Parcels/Lots

Parcels are displayed in the graphics when you import a LandXML file. You can select the lines to get basic information, and you can drill down into the Project Manager to see more details. The points that define a Parcel are stored in the CgPoints section of the LandXML file. If you want to see the point numbers on the screen, then you need to load the CgPoints. If you want to stake the points, then you need to load the CgPoints into the Points DB.

Chains/Figures

These LandXML items may or may not appear, because a chain can cross from one CgPoints set to another. This means that if you do not have all the CgPoint sets loaded, then the chains cannot appear.