Topographic Surveying 



Location: Port of Brownsville

Client: Port of Brownsville Engineering Department

Topographic surveying has been crucial to civil engineering and land management. However, as technology advances, so do the methods we use to map our world. PTC Aerial Mapping & Surveying Technology gives the advantage of collecting, analyzing, and visualizing topographic data more efficiently, accurately, and accessible than ever before.

Traditional Topographic Surveying Methods

Total Stations are electronic/optical instruments used for traditional topographic surveying for decades. They use electronic distance measurement (EDM) and angle measurements to calculate precise surveyed points, which are then processed and analyzed to create topographic maps. Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) technologies have also played a significant role in topographic surveying. Still, they can be affected by multipath errors and satellite signal obstruction in densely vegetated or urban areas.

Despite the advancements in traditional topographic surveying methods, there are still several limitations and challenges:

  • Time-consuming: Traditional topographic surveying methods require considerable time and effort, particularly for large-scale projects.
  • Labor-intensive: Total Stations and GPS/GNSS surveys often require multiple field operators, which can increase project costs.
  • Accessibility: Difficult terrain, dense vegetation, and other environmental factors can limit access to survey areas and affect data quality.

PTC- Aerial Fixed Wing Drone Topographic Surveying

PTC utilizes a drone with advanced technology that is different from the typical drones. The drone is connected to the Survey Grade Base Station VRS Network; the same method survey crews use to connect their GPS Rover. While flying, the drone takes pictures and collects ground laser data, which results in the collection of thousands of points. The accuracy of the data is measured in real-time utilizing an “RMSE” report. Ground control data is collected through a traditional GPS base station and compared with the drone data. Suppose the drone data is within 1-2 inches of the elevation ground control data. In that case, the accuracy of the topographic data has been proven, and confidence in the data is established.

The Benefits of Hiring PTC Aerial Mapping & Surveying

Suppose you need a drone pilot with extensive experience since 2014 for your topographic projects. In that case, PTC may be a reliable and professional option. PTC offers a range of deliverables to meet your specific needs, including:

  • High-resolution Orthomosaic Maps: Detailed aerial maps accurately represent the surveyed area; measurements on Horizontal XY are within 1-inch accuracy. Z elevation data 1-2 inches or tighter.
  • Digital Surface Models (DSM): 3-D terrain models, including buildings and other structures, allowing for accurate volume measurements and elevation data.
  • Digital Terrain Models (DTM): 3-D models of the bare earth, with all above-ground features removed, providing a clear view of the underlying topography.
  • Contour Maps: Topographic maps with elevation contour lines are helpful for planning and development. They are overlaid on Map Imagery as well.
  • 3-D Point Clouds: Dense 3-D representations of the surveyed area, suitable for detailed analysis and modeling.

PTC can collect planning data from surrounding areas without right-of-way access. This approach helps identify potential elevation issues of stormwater flowing from adjacent regions. For instance, PTC can scan a 100-acre area when your project area is 50 acres. The more data, the better.

The services provided can benefit civil engineers who lack the necessary manpower or large engineering firms seeking to save time. Land developers who hire PTC can save time and money; for example, PTC can quickly scan two parcels of land, 100 acres (200 acres total), and finish within a week, typically for what one parcel of traditional surveying would cost. Still, you get the data faster to hand over to your engineer. This survey data can be used for feasibility studies and engineering plans, allowing for a cost analysis of different plots of land. This service eliminates the need to wait months for a detailed topography survey to be completed by a standard man crew.

Another thing to remember is that PTC captures data every foot, which helps calculate earthworks for cut and fill more accurately. Traditional man crews take elevation points every 50 or 100 feet to get a general sense of the terrain. Civil engineers prefer to have detailed topographic maps in 1-foot grids and 50/100-foot grid files for an overall view and smooth contours.

PTC offers assistance with advanced technology and professional expertise, providing clients with high-quality data to make informed decisions. To learn more about PTC Aerial Mapping Services, visit

Joey Cepeda
PTC Aerial Mapping & Surveying


Joey Cepeda