**1. Introduction: from a classical naturalistic approach to a contemporary quantitative approach**

Research in coastal geomorphology aims at describing the shapes of coastal landforms (dunes, beaches, cliffs, estuaries, deltas, shorefaces, etc.) at different temporal scales (long to short term, several thousand years to a few hours) and spatial scales (over large to small areas) and understanding the processes of their evolution [1, 2]. This research is frequently applied to the study of risks, for example, in case of shoreline erosion, the evolution of the coastline is mapped, and sediment budgets are calculated to define the hazards threatening human infrastructures.

Many methods are used to detect shoreline changes. They can be classified into three categories depending on the date and duration of the study period and the type of tools used [3].

To map the medium-term coastline evolution from secular to multi-decadal scale and in two dimensions (in plan), diachronic analysis of historic maps, aerial photographs since the mid-twentieth century, and more recent high spatial resolution satellite images are often used. On historic maps that are often imprecise in their drawing, it usually results in approximate measurements. However, they represent valuable documents for a qualitative or naturalistic geo-historic analysis of landscape [3, 4]. On these maps published since the end of the nineteenth century and on vertical aerial photographs available since the 1930s, the successive positions of the coastline can be identified, digitized, and then compared in a Geographical Information Systems (e.g., [5–7]) in order to determine erosion or accretion zones.

Within the second category of methods, in the shorter term, over the last 30 years or so, measurements have been carried out in two ways with high-tech instruments. First, geodetic instruments (e.g., total electronic stations and GNSS) are used to carry out data collection in the field. These measurements are timeconsuming and difficult to carry out over large areas; only a fairly limited number of points can be acquired (a few hundred to a few thousand); therefore, only beach profiles (cross section of the range from a few tens to hundreds of meters long) or Digital Terrain Models (DTM) of limited size (a few thousand square meters) and low spatial resolution can be surveyed. Second, also in the short term, telemetry instruments (e.g., ground or airborne LiDAR) that enable the rapid collection of a large amount of elevation data that are transformed into DTM are used.

The third category encompasses the methods of photogrammetric processing that allow to extract elevation data from aerial photographs; this technique also allows to collect a very large amount of data that are transformed into Digital Surface Model (DSM).

The evolution of these techniques can also be conceptualized in a "measurement method paradigm" (**Figure 1**): with the methods of the first category, we start from the images to make measurements. Paper images (maps or aerial photographs) available in paper format are scanned or acquired directly in digital format; geometric deformations are corrected, and they are georeferenced; measurements are then carried out and statistically processed. It should be noted here that the analysis is in two dimensions (in plan). With the methods of the second category, measurements are performed and transformed into images (DTM and DSM), which are the result of calculations and not a direct capture of the reality of the terrain. One of the major interests of these methods is to be able to work in three dimensions: the measurements made are in plan and in altitude. The third category closes the paradigm: the work process starts with images (aerial photographs), continues with measurements, and returns to images (DSM). Here, the analysis is also in three dimensions.

This paradigm has undergone a twofold evolution over the last 25 years or so. First, the transition from 2D to 3D measurements has been a determining factor in coastal geomorphology. This has made it possible to objectify the position of the coastline, which is not always easy to detect in 2D aerial photographs [8]. This also made it possible to calculate volumetric and not just planimetric changes in beaches and dunes. In addition, with LiDAR technology and photogrammetry, there has been a progress toward higher density and accuracy of measurement and results.

The first part of this chapter is devoted to a technical and conceptual synthesis. A bibliometric analysis shows the recent, rapid, and phased success of the use of GNSS, LiDAR, and then airborne photogrammetry in the field of coastal geomorphology. We will briefly describe the techniques, emphasizing their complementarities and their spatial and temporal scales of application. The second part of this chapter is an illustration of the first by selected examples of results obtained on the coast of northern France. The conclusion proposes a synthesis of the advantages and disadvantages of these techniques and discusses some future prospects.

**93**

**Figure 1.**

*Recent Advances in Coastal Survey Techniques: From GNSS to LiDAR and Digital…*

**2. From GNSS to LiDAR and photogrammetry: three successful technologies aiming to a higher density of measurements**

further developed and progressively introduced.

**2.1 A rapid growth in the use of these techniques**

diverse and operate at different spatial scales.

*2.1.1 In environmental sciences*

*The measurement method paradigm.*

The use of these three techniques in Earth and environmental sciences began about 30 years ago. They have achieved rapid and phased success as they have been

In environmental sciences, the applications of these three techniques are very

*DOI: http://dx.doi.org/10.5772/intechopen.91964*

*Recent Advances in Coastal Survey Techniques: From GNSS to LiDAR and Digital… DOI: http://dx.doi.org/10.5772/intechopen.91964*
