This Client Server article is republished in its entirety from 2005 for reference purposes.

By Bentley Technical Support Group, PE, MX Support Manager, Bentley
23 May 2005

Bentley offers three civil engineering highway design packages, based on the MXROAD, InRoads, and GEOPAK product lines. Originally, these solutions were developed by competing vendors, and had completely different database structures and different terminology to describe the data. Each of these vendors realized that customers needed to transfer design data between packages, and there needed to be a standard for design data transferability.

All three became part of the LandXML.org organization, which developed the industry standard called LandXML.

LandXML, now adopted by many software developers, is used specifically for intelligently moving civil engineering design data between different software packages.

It is important to emphasize that LandXML is for the exchange of design information. It is not for exchanging drawing information.

Bentley now owns the MXROAD, InRoads, and GEOPAK packages, and continues to develop them. Bentley continues to improve the implementation of the LandXML standard in each product line.

This article will give tips on how to transfer civil engineering design data between the MXROADS, InRoads and GEOPAK.

Why is LandXML Important?

LandXML.org is a non-profit organization with many vendor members. Together, these members developed an industry data definition standard that could be read by many application programs, and to which many applications could write, without relying on individual vendors' terminology or data standards.

LandXML Will Not Convert All Design Data

While LandXML offers great benefits to users who need to exchange design data between software applications, it won't magically convert a complex design in another application, leaving it ready to go. Different applications work in completely different ways. The LandXML is a neutral file format, and each application does the best it can to create data in this format, from its own data format.

Things to Know Before Using LandXML

When you generate LandXML files:

Provide meaningful names
Provide features in XML files
Provide plan drawings to show spot elevations, breaklines, important features and alignments
Provide a description of the file contents

When you are given a LandXML file to process:

Know what the data roughly looks like - get drawings with the data.
Identify what features were exported so you can map them to the appropriate features in your application.
Use the data for what it is: design data. If you need drawings, reference in original drawings from the originating application.
Determine the software version of the originating application and the version of your software. Try to make sure that both are the current versions. LandXML data generated by a current software version may not read in correctly with an older software version.
A LandXML file can contain triangulation data, coordinate geometry data and alignment data. Identify what type of data you will need to transfer.

Exporting LandXML Data From MX

Exporting is a simple process. In short, you simply tell the software application what to export, and it does it:

Select File > Export > LandXML...

Importing LandXML Data into MX

You can import all data into a single MX feature, but that won't give you much information in MX about the data.

The preferred method is to map each element in the LandXML data to features in MX. This allows you to distinguish between centerlines, road edges and other features that may be contained in the LandXML data.

The more effort you make in mapping the features, the better your end results will be.

Select File > Import > LandXML...
You must tell MX how to map the LandXML elements to MX models and strings, otherwise, no data can be imported.

You can import COGO data, surface data and alignment data into MX. In all data types, you will need to identify the model name to put the data into, and the feature and style sets associated with the data.

You should always define a default mapping, and preferably, the individual feature mapping to get good data.

Mapping COGO Data

LandXML COGO data becomes MX feature strings.

Mapping Surface Data

LandXML Surface data consists of triangulations, breaklines, and boundaries.
In MX, if there are breaklines and/or boundaries, then you can create a string model from them.

Mapping Alignment Data

LandXML Alignment data becomes MX master strings. Corresponding MX geometry strings are also automatically created.
To import an alignment that has tangent to tangent connections, you must use a project that allows non tangential alignments. This type of project is only available in MX 2004 Edition and is defined when the project is created via the MX Startup Panel. It is strongly recommended that use MX projects that allow for non tangential alignments.

Importing and Exporting LandXML Data from InRoads

By default, the export and import of LandXML is not available in the menus. You have to turn this feature on:

On the main InRoads menu, select Tools > Application Add-ins
Scroll down to the bottom of the list. Make sure that XML Report Add-In is checked on
Select OK

Exporting LandXML Data from InRoads
LandXML data is exported in two separate stages: surface and alignment. Designs can be exported both as a surface and as alignments.

The surface contains the features. To export a design surface you have to model the road before exporting.

Existing terrains would only be exported as a surface, as they usually don't have alignments.

How to Export Alignment Data

Make sure that you have the road project(s) open. In the InRoads main menu select File > Open, and select the project(s)
Select File > Translators > LandXML
Identify the Geometry Project and the Alignments to be exported
How to Export Surface Data

On the InRoads main menu, select File > Translators > LandXML
Identify the items such as triangles and features you wish to export.
Importing LandXML Into InRoads
LandXML data is imported in one process and assigned to either surface or geometry depending upon the data found:

Importing Alignment Data

Make sure that you have the road project open with the correct geometry. In the InRoads main menu select File > Open, and select the project(s)
Select File > Translators > LandXML
All geometry found in the XML file will be imported as alignments. With surface data, by default, InRoads will automatically assign a single feature type to imported data, however, if you have features defined in the LandXML file, and in the Feature Style Manager, additional mapping will take place.

Exporting LandXML Data from GEOPAK

LandXML data is exported in two separate stages: geometry and DTM.

How to Export Geometry Data
The export LandXML geometry functionality is accessed from within the COGO dialog:

Select File > Export > LandXML 1.0 Geometry
Specify your project name and description, and also the element type and whether to export both Points and Chains. If you choose to export chains, you can also export your profiles.

How to Export DTM Data

DTM data is only exported in the form of a TIN: the actual DTM (the GEOPAK DAT file) is not exported. Hence you have to create the TIN from the DTM data before exporting.

In the DTM Toolbar, select Utilities > Export LandXML

Importing Geometry LandXML Data into GEOPAK

From the COGO dialog select File > Import > LandXML 1.0 Geometry
How to Import DTM Data
The DTM export LandXML functionality can be accessed from either the DTM Toolbar or from the DTM Tool Palette

In the DTM Toolbar, select Utilities > Import LandXML

Notes on Importing into GEOPAK

Only alignment geometry (including profiles) and DTMs can be imported. Survey chains cannot be imported, at present.
If a LandXML file contains both geometry and DTM (as is possible with MX), you have to import the data twice: once into COGO and the other into DTM. When imported into COGO the DTM data may cause errors. However, the geometry data will be imported as expected. When imported into DTM, the geometry data is ignored.
Due to the differences in the way different applications work, the names of geometric alignments may be incompatible with GEOPAK. When this happens you get a message box asking you for a new name. An alternative is to modify the name of the chain by editing the LandXML file in a text editor.

Comments or Corrections?

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Using LandXML To Transfer Design Data Between MXROAD InRoads And GEOPAK [CS]