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As-built Water and Sewer Workflow

Workflow

The work can be summarized in the following steps:

Procedure

  1. Create an application layer in Gemini Terrain with the template Gemini_VA.al_ or Gisline_VA.al_
  2. Export the object catalog (properties and codes in the application layer) to field PC/field book
  3. Import object catalog in field PC/field book
  4. Survey the water and sewer network and register at least the theme code on the objects
  5. Import survey data to a draft layer, or directly to the delivery layer
  6. Run visual inspection of survey data in plan and 3D
  7. Edit geometry as needed (split, merge, remove duplicates, etc.)
  8. Add missing properties and any attachments
  9. Copy data to delivery layer based on either the Gemini_VA or Gisline_VA template
  10. Export survey data with attachments to gmi or SOSI

Below we elaborate on the process in more detail for deliveries to municipalities that use Gemini VA.

Tip

We refer to Exercise 5.9 Water and Sewer Delivery to Municipality for a detailed description of the procedure in Gemini Terrain.

Content of a Water and Sewer Data Delivery

First, let's look at what is included in a water and sewer data delivery.

Figure: Overview of components in a water and sewer data delivery

From the figure, we see the following:

  • Various line objects (water pipe, sewage pipe, ...) with geometry and properties
  • Various point objects (manhole, manhole cover, drain, ...) with geometry and properties
  • Polygon objects, special manhole constructions where the outline is surveyed
  • Quality coding on coordinates
  • Various types of attachments such as documents and photos

How this data flows from the field to the utility manager can be seen in the figure below.

Figure: Data flow from field work to utility manager

Common Code System and Object Catalog

As mentioned above, we use the same code system in Gemini Terrain and Gemini VA. We solve this by including a template in Gemini Terrain called Gemini_VA.al_. The template contains a standard code system (object catalog) for the central as-built properties that executing parties typically register. If a municipality has created its own codes beyond the program standard, we currently need to add these manually in Gemini Terrain.

Export and Registration of Data

The Object Catalog (properties and associated codes) can be exported to a field PC/field book. Gemini Terrain supports the three instrument vendors, Leica, Topcon, and Trimble. This will give users access to the management system's properties and codes directly in the field.

Tip

How much is practical to register in the field must be determined by the individual surveyor. For example, we can register theme code in the field and add the rest in Gemini Terrain after the survey data has been imported. It has also become very common to take pictures of manholes when collecting data.

Many municipalities have their own survey instructions for as-built data. We are thinking of documentation of new facilities. For these jobs, the surveyor normally has access to the facilities before they are buried. Issues related to surveying "old facilities" will not be discussed here. For these facilities, there might be practical problems measuring the bottom inside a manhole, we don't hit the center of the manhole with the prism pole due to eccentricity, or the manhole is simply too deep for the pole.

Note

All objects (installations) must have a local project ID (S_OBJID in Gemini Terrain). The objects are numbered according to the project's drawing basis, for example K01 for manhole number, and retain their ID throughout the project. In projects without numbered installations, it is common to clarify the numbering with the utility manager before starting.

Presentation Rules and 3D Visualization

The Gemini_VA.al_ template also contains presentation rules for plan and 3D visualization. In 3D, we have the presentation rules Manhole/Manhole Cover for points, Pipe for lines, and Parallel/Surface for polygons. These presentation rules describe the volume using parameters.

We can choose to use fixed values for the parameters or have the rule retrieve values from the object. Fixed values for some parameters are included in the Gemini_VA.al_ template. If we enter values for the other parameters, we get the presentation rules to create volumes from the measurement points:

  • Manhole
  • Manhole width
  • Manhole shape
  • Cone
  • Manhole cover
  • Diameter
  • Pipes
  • Dimension

If we register values for these properties in the field, we will automatically get a 3D presentation after importing the survey data in Gemini Terrain. This will give us a good visual presentation of the completed facility.

Figure: 3D presentation of water and sewer facility in Gemini Terrain

Processing Survey Data

After importing survey data, some processing is typically required in Gemini Terrain before the delivery is ready for Gemini VA. Processing survey data typically involves:

  • Editing errors in geometry, such as joining pipes between installations
  • Supplementing/changing missing codes
  • Attaching other attachments such as manhole sketches, etc. to the installations

Figure: Editing surveyed water and sewer data in Gemini Terrain

Exporting Data

When we have finished this post-processing, we can export the data to gmi (for municipalities that have Gemini VA) or SOSI-GML for other utility managers.

Info

When exporting to SOSI-GML, Gemini properties and codes will be converted to corresponding SOSI properties and codes.