Whenever we want to change the place that we live we first need to know what our current place looks like. We need to take accurate measurements and be able to communicate these easily to other people. People who will have different skills to help change the place that we live.
When we are wanting to change larger areas of the places we live we will need to employ some sophisticated methods of measuring the places that we live. This may include wanting to build new homes, large shopping outlets, warehouses, airports or road and rail connections throughout the country.
With an increase of the size of the project that will change the place that we live, so will the challenges of measuring the land that we will be building on.
Measuring and mapping the desired area land is called Land Surveying.
This is the Purpose and Importance of Land Surveying.
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What is the Purpose of Land Surveying?
The purpose of land surveying is to accurately measure the existing land. This is not only in a three-dimensional manner but also measuring features that can be either on the land or below it. The Land Survey should identify whether the land is suitable for the planned project.
Without proper knowledge of the existing land, planning and design will be poor and ineffective.
Land Surveying is the start of any project that will be undertaken when trying to change the use of a particular area of land. The land survey will enable designers to create wonderful new designs quickly and easily if they know what the existing land looks like. A good quality land survey will ultimately save money for the client.
To be able to accurately record the topography of the land in question and then to portray it in a manner that can be understood by many other people is the purpose of a Land Survey. This is where the skill of the Land Surveyor is critical.
Why is Land Surveying Important?
Before we can start building anything new to improve the area that we live in we need to know what the land looks like. This will help the design of what we want to create be efficient and sympathetic to the current environment.
A Land Survey should also identify any potential issues with the place we want to build on or change. The land that we may want to build on may not be suitable for what was envisaged for the area. This may not be evident at first, but with a good Land Survey costly mistakes can be avoided. It is mightily embarrassing to find that the planned project is too big for the land designated for it when construction is about to start.
Knowing the topography of the land is vitally important to any planned project.
Taking measurements of the existing land will be the base of any new design of buildings, warehouses, roads, or rail construction that we might do. Whenever we want to change an area of land, we will need to measure it. We will need to record what it looks like. We also need to communicate this effectively to other people. We might also want to change the land into park land, recreational parks or woodland areas.
What is the Role of the Land Surveyor?
The Land Surveyor is the person (or team of people) who measures, records and creates a drawing of the land in question. A land surveyor will use many different types of measuring instruments during the land survey. Instruments like the automatic level, a total station, gps surveying equipment.
Modern surveying equipment has revolutionised the accuracy that the Land Surveyor can measure too. Along with drawings being processed with specialist survey software and AutoCAD there is no longer an issue with scaling from drawings. This means that the survey detail accuracy no longer has to be relative to the plot scale of the drawings produced.
The surveying equipment that is chosen by the Land Surveyor will depend on the size and nature of the land to be surveyed. Whatever the type of land to be surveyed it will need to be done accurately. Most land surveys will require an accuracy to within a few centimetres or less. It will most likely take several days out on site. One of the first jobs for a Land Surveyor on site would be to establish control points around the site. These control points will most likely need to be set to a national or local grid.
Once the land surveyor has taken measurements in the field, he/she will need to create scaled drawings showing all the information they have collected. These scaled drawings should clearly communicate how the surveyed land looks. Several drawings maybe required to do this. Even though these drawings will be done on a computer, there is still a need for several drawings. These drawings should be able to clearly communicate what the land looks like. Quite often the AutoCAD drawings have too much detail to be understood clearly.
What do Surveyors Use to Measure Land?
Land Surveyors will use many different instruments to take measurements during a Land Survey. What instruments the Land Surveyor will use will depend on the size and nature of the land being surveyed. I think that the most useful instrument for most land surveys carried out is the Total Station. The Total Station will take measurements and give three dimensional points to millimetre accuracy.
Land Surveyors will ultimately use a wide range of measuring instruments. Too many to be able to cover in this article. A full article on the equipment that a land surveyor can use can be found on this website. The article is called The Surveyor and Surveying Equipment.
What should a Land Survey Include?
The client should specify what is of interest for specific Land Surveys. Every survey that is requested will have special areas of interest. But there should be certain features that are included in every land survey carried out.
When doing a Land Survey, the minimum level of detail I would provide is:
- Control Stations around the extent of the land to be surveyed. There should be enough primary control to allow the accurate measurement of the whole site. Unless otherwise requested this should be to national grid co-ordinate system.
- Ground Levels, ideally in a grid format. This will depend on the current nature of the land being surveyed. A Land Survey will need to show contours of the land. This would include the top and bottom of any batters that might be evident.
- The outline of any buildings that might be present. Permanent or temporary.
- Any drainage features that might be evident. Gullies, Manholes, Downpipes and Rodding Eyes for example.
- Any road features that may be present. Channel Lines, Kerb Lines, Centrelines, Back of Footway, Pedestrian Crossings and street furniture. If no roads are present on site then I would pay attention the entrance of the land to be surveyed. If live roads do need to be surveyed then usually the closure would be the responsibility of the client.
- Any visible boundary features like walls or hedges or fences.
- Any visible utility services. Fire Hydrants, Water Stop Valves, Telecom Chambers, Electricity Poles and any Cabinets that are evident.
- Any vegetation areas that are present. The edge of any woodland, or shrubs and individual trees.
- Any water features. The edge of ponds and lakes, fountains, canals, and rivers.
- Any Railway features that might be present. Rails, Overhead Lines, Structures, Signals, Gantries, Telephones and Ducts. Any survey of the railway would need access to be organised and granted by the client.
The detail for any land survey will differ. The requirements will be different for every country too. In the UK the Royal Institute of Chartered Surveyors has guidelines for the accuracy and what should be included in a land survey. This link will take you to the current guidelines for Land Surveys. https://www.rics.org/uk/upholding-professional-standards/sector-standards/land/measured-surveys-of-land-buildings-and-utilities/
One of the first tasks that I carry out when doing any survey is to take lots of photos of the area. These prove invaluable when drawing up the survey. This is especially helpful if someone else is doing the drawing and has not visited the site.
What is the Accuracy of a Land Survey?
The accuracy of the Land Survey should be within plus or minus 20mm. For Land Surveys accuracy is now considered to be the distance between the recorded survey measurements and the true (real world) measurements. Project specification may require an accuracy greater than this. This accuracy is for hard fixtures. Soft fixtures like loose soil and plants and shrubs can have a lesser accuracy. This is due to fact that these fixtures can be altered easily by natural occurrences.
The accuracy of the land survey is achieved by the eradication of systematic errors, gross errors and random errors. These errors can be present whenever a measurement is taken. Only by identifying and removing these errors from the land survey can the desired accuracy be achieved.
Identifying these errors is one of the skills of the Land Surveyor. There is more information on measurement errors and how to avoid them on this website.
As a rule, the greater the accuracy required the longer the land survey will take. This is due to the extra time required to find and remove the systematic, gross and random errors that are present. The greater the accuracy of the required land survey will also increase the cost of the survey.
Modern survey equipment and CAD software have increased the accuracy achievable for Land Surveying. Over the last 20 years the Land Surveyor has had to ensure that all the measurements taken are as accurate as possible.
These advances in equipment and software have eradicated the scaling errors that would be present on scaled drawings. Scaling errors will occur whenever we create a scaled drawing from our real-world measurement. And then we will have a compound error from scaling the drawing back to the real-world dimensions or taking measurements from the drawing.
Conclusion.
Land Surveys are the foundations to any successful project. We have learnt why we need a land survey is important to understand the land that we currently have. We have also learnt the purpose of the land survey and how we can use it for our intended future function of the land.
Getting the right Land Surveyor for the survey that is required is essential. Getting quotes from several land surveyors is essential for getting the right price. Remember that the cheapest price is not always the best price. If you have not used a particular land surveyor then it is always good to get some references or to look at previous work that they have produced.