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Introduction

Shapefiles are at the very heart of GDMS data processing and delivery, and they represent the start of the round-tripping process for the contractor.

Shapefiles are geometric data files that contain complex three-dimensional geometry of any type of objects and carry linked attributes that can be used to describe anything the user wishes about each object.  Shapefiles come in three different types to describe three different types of object:

• Point – describes point items in geographical (coordinate) locations and their attributes.  Drawn as dots on a piece of paper.

• Line – describes line items that can be any shape.  Drawn as a line that has two ends and does not enclose a space.

• Polygon – describes closed shapes of any size and shape.  These are shapes that can be filled in with a coloured pencil on a piece of paper.

A Shapefile of any type is not a single file.  To many people, it is a strange concept because they become used to a single file .xlsx representing a spreadsheet from Microsoft Excel, or a .jpg file being a photo on their mobile phone, but a ‘shapefile’ is a collection of files that combine to make the total product.

There are a number of files included in this bundle, with a minimum of three files with different extensions and an unknown maximum number of files that are used by different GIS data software applications.

In any one bundle of files in a shapefile, all of the files must have exactly the same file name and only the file extensions (the letters after the dot) change for each part.  It is because of this that the file renaming utility tool is recommended in the Software Requirements section, because it allows the user to make a selection of several files and rename them at the same time, thereby removing the chances of human error.

It is common for users to make comments like, “I have received these files and I don’t know how to open them.”  This is where WinCan Map VX comes in.  WinCan Map VX is a full GIS application that is built and design for working with shapefiles and also communicates at all times with your WinCan VX database project.

Because of the nature of shapefiles being a collection of individual files, it is common and normal to share and distribute shapefiles in a .zip format so that the entire package is bundled up into one easy-to-handled file.  Furthermore, the GDMS upload process requires the shapefiles to be zipped.

The mandatory files included in a shapefile bundle are:

• .shp – this file contains the actual geometry and coordinates of the objects in the file.  We never try to open or edit the .shp in any application that is not a GIS application.

• .dbf – this is a database file that can be opened and edited using the .dbf file viewer application mentioned earlier.  They can also be opened and viewed in Excel, but this is not recommended for two reasons – because it is not normally possible to save any edits in Excel, and GDMS detects .dbf files that have been opened in Excel as corrupt and rejects them.  This file contains all of the attribute data for the objects and care should be taken with reading this.  A common mistake is to assume that because the COVER_LEVE (i.e. the cover level field) is defined in the Point.dbf file, then this must mean that the point is plotted at the correct altitude, but this may not be the case, because the .shp file contains that actual Z value, and the .dbf file contains nothing more than a data attribute of that point, which can realistically say almost anything.  It is possible to open and edit the .dbf file on its own outside of a GIS application, but it is not recommended.

• .shx – is known as a cross table in database terms and creates the lookup links between the geometric shapes in the .shp file and the attribute data in the .dbf file.  We never try to open or edit the .shx in any application that is not a GIS application.

There are many non-mandatory (and quite common) files that can and often are bundled with shapefiles, and these include:

• .prj – this is the projection file that describes where on the surface of the planet these coordinates are located.  This is because we are working in metric metres in these shapefiles at all times, and there are simply too many metres around the globe to have a single projection, and for large countries (like USA), the curvature of the globe means that it is very difficult to plot points in a single Cartesian coordinate system.  It is possible to open and edit the .prj file on its own outside of a GIS application, but it is not recommended.

• .shp.ini – these are WinCan files that are used to define design themes for shapefiles loaded in WinCan Map VX.  It is possible to open and edit the .shp.ini file on its own outside of a GIS application, but it is not recommended.

• .shp.ttkstyle – the same as .shp.ini and work in the same way, but a more robust file format.  It is possible to open and edit the .shp.ttkstyle file on its own outside of a GIS application, but it is not recommended.

• All others – are either temporary files used by the GIS application or other types of controls, but in all cases, we never try to open them in any other software application.  We just leave them as they are inside the shapefile directory.

When people see shapefile data of a drainage network in WinCan Map VX for the first time, there is a common misconception that when it is a version of a CAD application, but this is not the case.  Shapefiles and CAD files are very different things, although there is a certain amount of interchangeability between them.

A crude a simple comparison is that CAD files are all about nice looking drawings, and shapefiles are all about the data, but both are usually dimensionally correct.

GDMS Shapefile Data

In the section Shapefiles, we described generic types of shapefiles, and these are used specifically in GDMS:

• Point – In GDMS data, this is called Point.shp and contains all the geometry and attributes of point the specified point items on the job including things like gullies and catchpits.

• Line – Known as the Continuous.shp shapefile in GDMS and carries all the data regarding line items like pipes and kerbs.

• Polygon – The Region.shp shapefile in GDMS, used to plot things like ponds.

There are two other files in standard GDMS download dataset that require some consideration:

• Component.dbf – this is a new file introduced with GDMS that did not exist in DDMS data. It is tied to the Continuous.shp file and contains all of the asset physical attribute data for the linear item and allows changes of attributes at points along the line.

• Observation.dbf – this is a .dbf file that stands on its own 2 feet with no other supporting files.  It is a database file that contains all of the observation data for all assets; point, continuous and region.

Finally, there are two more files in a standard GDMS download dataset that do not require any attention at all unless it interests you.  WinCan VX extracts some information from them at the initial import stage of the round-tripping process, but after that they have no more use to the project.  The best advice is to just leave these where they are and do not delete them:

• Linkdata.dbf – this is a .dbf file that contains information about the Priority Register field values and the numbers of attached documents per asset in the data, and the objects that they relate to.

• Metadata.dbf – contains some information about this set of shapefiles that can be read in a .dbf file viewer and can be used to enhance the Job data in your project.

Reviewing the Shapefile Data

So, you’ve received some shapefiles maybe for the first time and they are GDMS files.  The first thing to do is to unzip the folder and copy all of the file contents to a regular folder on your PC, and the contents will look something like this:

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Inside the folder above, you will see that there are 3 point files (Point.shp, Point.shx and Point.dbf), 3 continuous files (Continuous.shp, Continuous.shx and Continuous.dbf) and 3 region files (Region.shp, Region.shx and Region.dbf).

These are the geometric shapefiles with their mandatory parts for the nodes, linear items and ponds etc.  Do not be surprised if there is no region shapefile in the data, it just means that there are no ponds in this catchment.

Then, there are 3 additional .dbf files; Observations.dbf, Component.dbf and Linkdata.dbf

 All files will always have the same consistent names.  This is how they are delivered by GDMS on download, in a zipped format, by any name required by the downloader.

The concept of catchments from DDMS has largely gone in GDMS. They still exist, but they are handled by the GDMS system and there is no longer any requirement to download and work on entire catchments at one time.

Schemes are also a thing of the past with GDMS data. There is no longer any concept of a Scheme in the database.

Loading Data in WinCan Map VX

WinCan Map can be used in two ways:

• Connected to a WinCan VX project database where there is a constant communication channel open between what is happening in VX and what is happening in Map.

• As a standalone software application that does not need a connection to VX.  After all, Map is a GIS application.

To simply load and review the shapefiles without any connection to a WinCan project (see the section WinCan VX Project Setup), you can add a shortcut icon to your desktop, start menu or task bar in Windows by navigating to C Drive -> Program Files (x86) -> CDLAB -> WinCanMapVX and then finding the file WincanMapVX.exe which will have a green W icon.  Now right click on this file and select any of the following options that you prefer:

• Pin to Start

• Pin to Taskbar

• Send To -> Desktop (create shortcut)

Now, you will have a ‘direct’ launcher for WinCan Map which does not need WinCan VX to be running in order to work.

For this shapefile data review, now click this button and launch WinCan Map.

In the Home ribbon, you will see some options in the Layer panel.  Click on ‘Add Layer’ and then navigate to the folder (must be the unzipped one) where your shapefiles are saved and select the Point.shp, Continuous.shp and Region.shp files to load.  This is another reason why it is recommended to have the file extensions activated on your PC, so that you can select the correct file here.

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The shapefiles will load, and depending on the layout of the catchment that you are working with and whether or not there are any region items in the data, you will see something like this:

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See the layers listed on the left-hand side (each one of these is a shapefile), the point items will load as small red squares, the continuous items will load as thin black lines and the region items will load as grey shapes.

However, it is very easy to apply some nice themes and colours to help you with identifying on screen what is what, and you can save these themes for future use once they have been created so that you don’t have to keep building them each time you want them.

We have created some built in themes for you in the application that can easily be applied to the layers by right click on each layer in the layers panel and then selecting ‘Load Theme’ → select the most appropriate theme and click the ‘Load’ button:

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Adding a pre-defined theme.

These themes will display the most relevant information for the items in each object group.

One of the most useful tools in WinCan Map VX is the Info Tool, which shows you all of the attribute data that is attached to an object.  In this example, we will select a point item and display the data attached to it:

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1. Select the point layer in the Layers panel.

2. Activate the Info Tool by clicking on the large button.

3. Click on the Object tool from the Select panel (more commonly referred to as ‘Select Object').  The fact that it is orange shows you that this tool is now active.

4. Click on a object of your choice and the information for that item will be displayed in the Info Tool.

Try this again with a continuous item for practice, and then try again using a Select Rectangle over several objects at once and see the list of items on the left-hand side of the Info Tool.

You will see in the Name column of the Info Tool of the shapefile field names that are listed in the .dbf file for the layer.  Those who have worked with GDMS data for a long time commonly refer to field IDs by these names, so it is not uncommon to hear people talking about the ‘Supp Ref’ of an object.  They are of course referring to the ‘Supplier’s Reference’ which is saved in the SUPP_REF field in the shapefile.

With the conversion of DDMS to GDMS, we now have to also consider the Component.dbf file which contains the physical attribute data for the Continuous assets. What this means is that there are no longer fields like material, size, shape and others in the Continuous.shp file because they are in the Component.dbf so how do we display and/or edit this data in WinCan Map?

We have developed a new feature for this:

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Link Data Tool.

First highlight the Continuous layer because this is the layer that we are linking external data to, and then hit the ‘Link Data’ button in the DMS ribbon. You will now navigate to the same directory as where your shapefiles are stored where you can select the Component.dbf and then you will see this pop up.

These settings are pre-defined for GDMS and do not any changes. Just click the green tick to continue. After you have done this, select one or more continuous objects and then see in the Info Tool that there is a new tab called ‘Linked data’. In here you will see the data that is contained within the Component.dbf for all the components that are linked to this continuous object.

Data can be reviewed and edited if needed here, and saved to both the Continuous.shp file and the Component.dbf file.

If you wish to theme the layers yourself to suit your own needs, the theming options in Map are extremely powerful and not for documentation here in full. The simplest theme is to simply change the colour of the small squares on one of the layers:

1. Right click on the layer of your choice and select ‘Show Properties’

2. Select the ‘Marker’ in the properties panel.

3. Change the colour to one of your choice.

4. Apply the changes and see that now this layer has changed colour.

5. If you wish, you can save this theme using the save icon button at the bottom-left corner of the properties panel.

The result is now clear to see and easy to work with.  With some experimenting and training, you will be able to create some user-friendly themes that really help you to navigate the data:

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In this example, we have extended the red and green colours to the continuous items, turned the small red squares into circles with a dark outline, activated the line direction arrows (right click on the layer in the Layers panel to do this) and added the SUPP_REF field of the point items as a label so that we can see which point is which.

Finally, try a right-click on a layer in the Layers panel and select the option ‘Show Data’.  This will display a table of the attribute data for the selected layer.  This is exactly the same data that you see in the Info Tool, but it is presented in a different way.

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