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Topographic Surveys

Introduction 

A topography survey is usually the 1st step in any development or construction project. For that, it’s done before the stakes are positioned or any other survey is conducted. Also, this type of survey offers a multi-dimensional illustration of a piece of land on a 2-dimensional drawing. Yet the information it contains is essential to every process of the project that will follow. At the same time, a topographic survey will help save a lot of money in the long run. 

Unfortunately, most people don’t understand how this survey type is performed. Or why it’s so important to have it performed before you embark on a construction project. That’s why in this article, we’ll take you through the basics of topographic surveying in California! 

What’s a topographic survey? 

First, topography refers to the study of the features and shape of the land surface. While a topographic survey is a land map that shows the depth, contour lines, as well as relative elevation of the land. More importantly, it shows the physical features, both man-made and natural, on the property. 

The information contained in topographic maps is important for infrastructure construction, development, and land planning. Besides, the included permanent features accurately define the land area as well as its boundaries. Engineers, contractors, and architects use the information contained in these maps to accurately visualize the site. 

Another thing that differentiates the topographic survey from other surveys is that it measures and studies the land surface. And its measurements are usually carried out using both EDM (Electronic Distance Metering) and GPS (Global Positioning System).

In summary, a topography survey shows the following elements on a specific prope3rty; 

  • Utilities. This refers to any man-made utility that is displayed in the topographical survey. Utilities include things like; pipeline markers, utility lines, and electrical boxes. 
  • Physical attributes & vegetation. A topographical map also identifies wooded areas, large boulders, and streams. 
  • Contours. As you know, contour lines show each valley and peak of the land. Thus helping the surveyor and contractor to note where there is a considerable drop in vertical height. 

Types of topographic/ contour surveys 

Topographic surveys can fall into different categories, based on the desired output and purpose of the survey. Also, these types may depend on the site location and scale of the survey. For instance, the survey can be identified by accuracy level, depending on whether the site is in a rural or urban area. 

In essence, a topography survey is a kind of land survey that identifies the boundary lines of a property before development. However, there are other types of contour surveys as well. They include; 

  • Geodetic survey 

This type of topographic survey involves determining and measuring certain points on the surface by considering the earth’s shape, size, and curvature. They use monuments or marks on strategic points around the planet marked by low earth orbit satellites. In most cases, these surveys are used to provide imagery for specific applications like disaster mitigation. 

  • Hydrographic survey 

Hydrographic surveys are used to map out water bodies, especially the oceans. 

  • Wetlands delineation 

This involves an evaluation that is conducted to determine the location and presence of wetlands on a property. Although the definition of a wetland may vary across different states, it includes features like bogs, fens, and swamps. 

When do you need a topographical survey? 

A topographic/ contour survey is needed when you’re planning to undertake a construction project, real estate transaction of civil engineering design on a piece of land. This applies to projects like; grading/ drainage projects, utility design, bridge/ road design, new construction, and remodeling projects. 

Moreover, most local government bodies require topographic surveys for the approval process to determine the elevations and existing conditions of a site. Lastly, engineers and architects use topographic surveys in conjunction with boundary surveys in the planning and design phase. This helps them to create accurate and ideal designs depending on the existing conditions of the site. 

How are topographic maps conducted? 

Conducting a topographic survey involves the use of a TST (Total Station Theodolite), EDM (Electronic Distance Measurement), and a surveying-quality GPS (Global Positioning System). These tools help to determine the location of each feature displayed on the map. 

In general, producing a topographic survey can be done using 3 different methods. That is; 

  • Total Stations

With this approach, the field crew directly maps out every feature within the site. For that reason, it’s a very effective technique especially when the vegetation cover blocks other surveying tools. The same case applies when the area has varying elevations or unique geological features. 

  • GPS

The use of GPS mapping technology is an alternative site survey technique for sites that aren’t large enough for the aerial approach.

  • Aerial 

The aerial approach involves the use of UAV and LIDAR photogrammetry technology to identify the contours of the site.  

Afterward, the results of the survey are presented on a site map as contour lines. Interestingly, you can manipulate these maps in CAD (Computer-Aided Design) programs to provide interactive views. 

How much does it cost to get a topographical survey? 

Typically, the average cost of a topographical survey depends on the time the surveyor spends on the project. This duration can be calculated based on the extent of your site area, visibility, and terrain. Moreover, the calculation will also consider the features that will be included in the survey map. 

How can InnoDez help with topographic surveys?

Topographic surveys have a wide range of applications in the construction industry. At InnoDez Design & Engineering, our experienced team will help you obtain a professional topographic survey for your land in California. Our expertise offers various land surveying services including new home surveys, land surveys, and other services needed in commercial and residential property developers. So, if you want to learn more about topographic surveys, contact us today! 

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