Geomorphology of the Beqaa Valley, Lebanon and Anti-Lebanon Mountains

: Geomorphology of Lebanon presents a unique pattern of contrasting landforms. These include two notable mountain ranges, the Lebanon and Anti-Lebanon Mountains, the Beqaa Valley, the elongated coastal area and a significant amount of karst relief forms. This study focuses on the investigation of the topographic and geologic setting of Lebanon by visualizing datasets covering Lebanon and Anti-Lebanon mountains and the Beqaa Valley. Data were collected using the open source repositories of the high-resolution data (GEBCO, ETOPO1, DEM embedded in R). Three 3D models of the relief of the country are presented based on the ‘grdview’ package of GMT with azimuth rotations of the view point at 205°/30° and 165°/30°. The geologic map is based on the compiled datasets of the USGS. The R based modelling allowed division of the raster grid into several geomorphological zones according to the slope steepness and aspect orientation. The extreme elevations of the study area range from -2007 m and 2973 m. The key contribution of this work is the topographic and geologic data synthesis for 2D and 3D modelling of Lebanon. Another aspect concerns technical integration of GMT and R scripting approaches with QGIS mapping into the cartographic framework for visualizing of the Lebanese topography as a multi-tool approach. For the future similar studies on Lebanon this paper can serve as a guide for completing a project on the multi-source 2D and 3D data mapping as a conceptual foundation for research on Lebanese environment. an application of combined of using and QGIS for thematic mapping of Lebanon aimed at 2D and 3D visualization of its contrasting The demonstrated various 2D and 3D modeling methods by GMT, R and QGIS and Lebanese terrain analysis using and specific with varied and The results are as a series of The topographic features of the setting The

Corresponding author: polina.lemenkova@ulb.be Full Paper DOI: 10.2478/asn-2022-0002 ©2022 Konstantin Preslavsky University of Shumen. All rights reserved Despite the existing efforts to map geomorphology of Lebanon, some maps are outdated, while others are either printed in a monochrome palette and lower resolution or have special thematic focus. This raises a question of the cartographic update of the area using modern advanced technical tools. The combined visualization of Lebanon by means of GMT and R is still lacking. This paper aims to fill in the existing gap by using the modern tools of numerical cartography for visualization of the Lebanese terrain. Technical methods used in this study include scripting techniques and present a first attempt with a systematic approach of the 3D modelling of Lebanon using an integrated use of the GMT, QGIS and R.

Data
The data used in this study have high spatial resolution and compatibility with cartographic processing. Following types of data were downloaded from the open sources online repositories and used for the study: i) GEBCO topographic grid in 15 arc-second resolution (GEBCO Compilation Group (2020) used for plotting The study area in Fig. 1 has been masked and overlaid on the neighboring countries with 60% transparency using the DCW layer (Digital Chart of the World) in GMT. This study was conducted in the area of Lebanon using a square mask of the study area at 34.7°/36.7° longitude easting and 32.8°/34.8° latitude northing.

Scripting in Generic Mapping Tools
The 3D modelling of the topography of Lebanon has been performed using Generic Mapping Tools JM6.5i -I+a15+ne0.75 -t60 -Xc -P -K > $ps'. The 'psclip' modue was used for clipping the area and overlaying it over the 60% transparent grid of the remaining image showing neighboring countries (Fig. 1).
The elevations heights in the digital grid serve as variables visualized using the 'world' (Fig. 1 and 5) and 'turbo' (Fig. 3 and 4) color palettes. The difference in the resolution grids of GEBCO (15 arc-minute) and ETOPO1 (1 arc-minute) is remarkably well illustrated by comparing Fig. 3 and 4 where the mesh plots visualize the same spatial extent modeled using different raster grids. The modeling itself has been performed using the following code snippet: 'gmt grdview lb_relief.nc -JM10c -R34.7/36.7/32.8/34.8 -JZ3.5c -  Respectively, for the Fig. 5 the last flag has been changed to '-p165/30'. This explanation briefly illustrates the usage of GMT presented and explained technically in more details in the existing works (Lemenkova, 2019d, 2020d). The code written in GMT syntax uses a scheme equivalent to the programming languages and used as a tool for cartographic automatization (Lemenkova, 2019e; Schenke and Lemenkova, 2008). These lines of code were then combined in a script and re-used for plotting the 3D images in Fig. 3, 4 and 5 with changed rotation, raster grid and color palettes. The GMT includes a wide variety of types of modules, several of which were used to plot maps in Fig. 1, 3, 4 and 5. Hence, the codes were aggregated into a single script for each of the maps to visualize raster images that map viewers would presumably want to compare.

Mapping in QGIS
Mapping in QGIS ( Fig. 2) has been performed using QGIS approach that includes the Graphical User Interface and menu and is compatible with the ArcGIS based format of the shape files (QGIS.org, 2021). This part of the study presents a qualitative visualization of the geologic vector layer made using import of the ArcGIS native format (.shp file) to the QGIS environment, and overlaid on the OpenStreetMap by the QGIS plugin. The map attempts to accumulate the existing geologic information on units, provinces and volcanics within the Lebanon using data captured from the USGS.

Modelling in RStudio
The geomorphometric modelling ( Fig. 6 and 7) has been performed using R programming language were done using 'raster' package of R based on DEM by RStudio using embedded algorithms of data processing in R. The geomorphometric analysis of terrain parameters of each site has been adopted after Doe  The 'raster' package provided an access to the SRTM 90 m resolution elevation data with the getData() function using this code: 'alt = getData("alt", country = "Lebanon", path = tempdir())'. Following that, the data were processed and modeled using special functionality of package: 'slope = terrain(alt, opt = "slope")' and 'plot(slope)'. The hillshade was calculated using parameters of angle at 40° and direction at 270° using the following code: 'hill = hillShade(slope, aspect, angle = 40, direction = 270)'. Pairwise plotting of maps (slopeaspect, hillshade-elevation) using identical spatial extent and map projection enabled to illustrate the relationship between the geomorphometric parameters in the Lebanon and Anti-Lebanon Mountains.  Fig. 3 and 4 at the view of 205/30° is sculpturally visible on the 3D model highlighting the influence of tectonic structure on regional geomorphology, which is also pointed in a variety of relevant publications throughout the last several decades (see Veyret and Vaumas, 1955;Khair, 2001). Two grids (ETOPO1 and GEBCO) are remapped for the same territory and rotation azimuth ( Fig. 3 and 4) using the two raster grids so that each demonstrates a difference between the topographic grids based on the GEBCO and ETOPO1 ( Fig. 3 and 4), respectively.

Results and Discussion
The    be by GEBCO (Fig. 1, 4 and 5), while the middle resolution is presented by ETOPO1 (Fig. 3) and coarse resolution was used in R modelling: Fig. 6 a) and b) and 7, a) and b). This paper has presented work that has attempted to demonstrate the possibilities for practical visualization of several topographic maps demonstrating the relief of Lebanon in 2D and 3D using design approaches by the GMT and R scripting tools.
The methodology has been based on cartographic theoretical principles of data generalization and practical solutions by GMT scripting toolset and R language. Apart from the spatial data processing there has also been demonstrated cartographic art and design creativity in the presented map series. All the three resolutions can be applied for various tasks in spatial visualization of the Lebanese topography: the finest GEBCO-based data can be used for detailed geomorphological modelling and interpretations of the landforms at the local scale, the middle ETOPO1-based resolution can be utilized for mapping selected regional parts of The presented paper demonstrated that Lebanon has a specific contrasting topography including coastal areas, mountain ranges with varied slope steepness and spatial orientation and inter-mountainous Lebanon presented an excellent data for cartographic modelling, terrain analysis and visual interpretation. The paper presents new 7 maps and contributes to the regional studies of the topography of Lebanon and development of the cartographic methods of integrated 2D and 3D data processing.