Survey Notes / Survey Draft
Survey notes are made directly on to a copy of the base map or on to one, two or three separate polyester sheets overlaying the base map. With two or three sheets, survey information is split between:
At the end of the survey session the information is transferred on to either a master survey draft or directly into the computer.
The survey draft
This is the up to date drawing of survey results from all sources from which the final map will be produced. The survey draft is both a record of survey and a clear presentation of the information for the final map. The way it is presented depends on the intended method of drawing: using a computer, pen and ink or scribing.
All line thicknesses on the draft should be scaled proportionally to the line thicknesses on the final map. This shows up any problems of displacement made necessary by drawing with thicknesses greater than the space taken up by the feature on the ground. Such problems should be resolved at this stage rather than at the final drawing. Where there is considerable density of detail, care should be taken to maintain legibility. It should be remembered that legibility increases when several colours are used rather than just a single colour.
One or more sheets - the survey draft is drawn on to one or more sheets depending on the complexity of the line work and method of cartography. When using more than one sheet, the line and point detail are drawn on seperate sheets to that containing the screen areas.
Lines and Areas - Ink pens (0.25 / 0.35 / 0.50 and 0.70 in black, red and blue) and black lead pencil are used for drawing lines and point features while coloured pencils are used for screen areas on the survey draft. Which are used and for what is dependent on the complexity of the map and method of cartography.
Colours - the colours used depends on the type of terrain, the most important detail being drawn in black. Thus maps with complex contours the following should be used:
The colours of the vegetation / open land / stony ground should be chosen to be as different as possible and it should be possible to show different shades in combination.
If the survey draft is drawn very clearly and in the correct dimensions, it can be used afterwards for corrections. A reduced colour copy may also be useful for initial course planning.
Survey draft for scanning
The complexity of the line work, whether auto tracing software is being used and the quality of the scanner (monochrome or colour and resolution) will determine whether the survey draft is drawn with one or more sheets. For simple areas or when using a high quality colour scanner without auto tracing a single sheet is sufficient. When using monochrome or low resolution scanners a multi sheet draft would be made. When not auto tracing two sheets would be sufficient, one containing the line and point detail, the other sheet containing the screen areas.
When using auto tracing software it is advantagous to draw the line and point detail for each colour on a separate sheets (since the tracing software does not distinguish different colours) and the screen areas on another sheet. To maximize the efficiency of the auto tracing software try to:
Survey draft for digitising or pen and ink
A survey draft to be used for digitising or pen and ink drawing can be drawn on a single sheet using colour to differentiate between the classifications of lines and areas. The map is either digitized or traced directly from the survey draft. The computer output can be produced at final scale while pen and ink drawings are photographically reduced to map scale prior to printing.
Is a survey draft required?
When drawing a map using a computer is it really necessary to produce a survey draft first or can it be drawn directly from the survey sheets? Both methods have advantages and disadvantages , the most important of which are described below:
Preparing a survey draft
This may increase time in the field *