Surveying - preparation of drawings

​Preparation of drawings for work surveying.

Connection to title boundaries 7.9

The alignment of all 'as constructed' works must be related to title boundaries and road alignments by means of offsets and ties.

Where Works are a significant distance from title boundaries or road alignments and have been co-ordinated, the 'as constructed' MGA94(z55) co-ordinates should be recorded for both the start and finish of Works. If Works haven't been co-ordinated and it's impracticable to relate to road/title boundaries by offsets and ties, bearings and distances to nearest intersecting title boundaries should be recorded for the purpose of locating the start and finish of the Works. All appropriate information must be annotated on the original design plans and be clearly distinguished from design offsets and ties, by prefixing the characters "A/C" (i.e. A/C 2.4).

Offset distances and tie distances must be quoted to one decimal place of a metre, with an accuracy tolerance being set at +/- 0.10 metres in respect to the adopted title boundary and be shown at all critical points, such as manholes, changes in alignments, tangent points and road intersections. Where the associated subdivision has been co-ordinated then MGA94(z55) co-ordinates must be supplied for all manholes, outlet/inlet structures, tangent points, changes in alignment and appropriate title corners to verify the relationship between asset and title.

Dimensions relating the asset to a title boundary must be certified by a licensed surveyor on the annotated original design plan (e.g. pipelines within an easement would require relationship to title and therefore a licensed surveyor's signature, whereas a wetland within a reserve doesn't necessarily require a licensed surveyor's signature).

Note: The 'as constructed' asset is positioned within our Geographical Information System (GIS) relative to VicMap Property using offsets and ties. The actual MGA94(z55) co-ordinates are stored as attributes to ensure there's no loss of data integrity, especially where VicMap Property is only captured to an accuracy of 1:2500.

‘As constructed’ requirements for digital format 7.20

We request any digital information created or captured during the preparation of 'as constructed' information and which conforms to the criteria stated below, be submitted as part of the 'as constructed' information. Provision of digital survey data isn't an alternative for the mandatory submission of annotated 'digital design plans' - it's in addition.

Our criteria for accepting digital survey data 7.20.2

  1. Digital survey data representing the geographical location of the 'as constructed' Works in respect to title boundaries

  2. The 'as constructed' information for both design plans and digital survey data should be in the same projection.

  3. The minimum requirements for digital survey data, is the 'as constructed' location of all assets, including relationship to title boundaries with surrounding mapbase, by offsets and MGA94(z55) coordinates. Any other information recorded by the Consultant/Surveyor for their purposes will also be accepted.

General rules for structuring the digital survey data 7.20.3

  1. to enable us to easily consolidate the provided digital survey data into our GIS, all relevant points of interest (i.e. tangent points, changes of grade, centre point of manholes, changes in horizontal direction) should have a vertex placed or be one of the end points of a line string

  2. spot levels must show the point at which the level was taken

  3. the centreline of all linear constructed works should be shown (i.e. pipe centreline, channel centreline and levee bank centreline)

  4. for channels, the toes, top of cuts and any ramps or beams are to be shown

  5. for levee banks, both tops and toes are to be shown

  6. for retarding basins and wetlands, features such as lakes and earthen mounds are to be shown as well as spot levels and generated contours where appropriate (i.e. spot levels may be more appropriate than cross sections).

  7. for assets such as lakes, wetlands and retarding basins, the Normal Top Water Level (NTWL) must be shown.

  8. a limited amount of text is required to assist with interpretation, such as manhole numbers, descriptions of unusual features, or road names

  9. line strings may be used to identify the location of 'as constructed' cross sections

  10. we don't require information linkages to be attached to graphical objects/elements nor wish to specify specific symbology (i.e. levels/layer names, colours, weights, styles, fonts, text size, etc.) to be used. The intent of not imposing these requirements is to ensure no software development is required within the Development Industry and to allow consultants to continue to maintain their own internal standards. Consultants also don't need to contend with obtaining our font libraries, cell libraries, code lists or colour tables.

Our preferred formats and projection 7.20.4

The following details don't constrain the consultant on how they prepare or capture the digital information, but provides our preferred formats to assist us in consolidating the 'as constructed' information into our GIS. 

Any digital data can be forwarded by email, CD or DVD. The naming convention to be used for the digital files supplied is as follows:

  • first four characters is the drain number (i.e. 0306)

  • fifth and sixth characters is our stage number for the works (i.e. stage 5 for drain number 0306 is 030605**.***)

  • seventh and eight characters are user definable (i.e. consultant to use as appropriate)

Preference one - MapInfo format (Version 8)

Our files are on the MGA94(z55) projection with its bounds/working area set with an easting range of zero to one million metres and a northing range of 5.5 million to 6.5 million metres. Setting the bounds as stated allows for data to be stored within MapInfo tables to a precision of one millimetre.

Example of format information to be used:

  • MAPINFO - ******.TAB ******.DAT ******.MAP ******.ID

Preference two - MID/MIF format

This is an ASCII format which can be imported directly into MapInfo format with associated attributes. The format is published and available on request from us. Bounds/working area as above. 

Example of format information to be used:

  • MID/MIF - ******.MID ******.MIF

Preference three - Microstation format (Version 8)

Although we'll accept the digital data in Microstation format in either 2D or 3D, our preference is the files are structured as follows:

  • global origin set at 214748.3648, 214748.3648.

  • working area set at:

    • master units = m (metres)

    • sub units = mm (millimetres)

    • resolution = 1000 sub units to a master unit

    • one position unit = 1 mm

  • these working units allow for one millimetre precision

A Microstation seed file providing this structure with relevant colour palette is available on request from us.

Example of format information to be used:

  • Microstation - ******.DGN

Preference four - AutoCad (2006 or earlier)

Co-ordinates provided in AutoCad format must be in accordance with a known published projection or for arbitrary co-ordinates, our preference is as per preference one.

Example of format information to be used:

  • AutoCad - ******.DWG

Preference five - DXF format

DXF format is a common interface for most geographical software packages and as such provides a format that can be readily created by the consultant/surveyor and received by us. Co-ordinates provided in DXF must be in accordance with a known published projection or for arbitrary co-ordinates as per preference one.

Example of format information to be used:

  • DXF - ******.DXF
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