Con Dao’s Positional Resources: Potential and Orientation in Value Promotion

Con Dao is an archipelago off the coast of Ba Ria - Vung Tau province, in the southeast Vietnam, including 16 islands with a total area of 72.81 km2. Through surveys and various secondary sources, the article focuses on analyzing the geo-natural, geo-political and geo-economic resources of Con Dao, thereby proposing the solutions to promote the position resources of Con Dao for sustainable economic development. Results indicate that topography, geology, and ecological landscape have created a great value for Con Dao in terms of geo-natural resources and favorable habitat for living species and humans. Regarding the value of geo-political position, as a protruding archipelago located at the crossroads of international sea routes, the intersection point of two maritime routes from South to North Asia and the maritime route from West to East and vice versa, and the gateway of Vietnam with ASEAN countries, Con Dao plays an important role in the protection of Vietnam’s past and current national rights and interests in the sea. In terms of the value of geo-economic position, Con Dao belongs to a district-level administrative unit in Ba Ria - Vung Tau province as a prioritized position for the development of the sea-island economy of the country. With the rich and diverse natural resources, human resources, healthy environment, and location in an important position on international trade routes, Con Dao is a favorable area for the development of marine economic sectors such as fisheries, marine conservation and tourism along with other types of services. However, in reality, the enhancement of the position resources of Con Dao for economic development is still limited, inconsistent and unsustainable.


Introduction
Vietnam is a maritime country, which owns a sovereign sea area of about one million square kilometers, together with a coastline stretching over 3,260 kilometers and a system of coastal and offshore islands occupying an extraordinary position with regard to national security -anddefense, as well as economicy and society.Vietnam is considered as a country with considerable advantages and potential in marine and island resources because 28 over 63 provinces of Vietnam, which account for 42% of the land area and 45% of total population, are located along the coast [1].Vietnam's seas and islands are located in the tropical monsoon area, playing an extraordinary role with regard to environment and ecology in the East Sea, as a special transitional zone between the Indian Ocean and the Pacific Ocean both in terms of biogeography and navigation [2], [3].With the current industrialization and modernization of Vietnam, especially the development of a service-based market economy, the potential of sea and island resources is of key value.Also known as Con Son or Con Lon, Con Dao is an island district in Ba Ria -Vung Tau province, located in the East Sea in the southern sea of Vietnam.Among Vietnam's islands, it stands out due to its location, topography and spatial structure.As Vietnam's gateway and a sea connection with ASEAN countries, Con Dao is located in the East -West -South coastal economic belt: Con Dao -Nam Can -

Conceptualization
Natural resources are not only understood according in conventional terms (physical forms can be obtained and used for certain economic purposes), but also understood as all natural elements which can be used in different forms, or as those whose existence benefits people.The position or positional resource has been discussed recently and is considered essential.According to Article 3, the Law on Natural Resources and Sea and Islands Environment (No. 82/2015/QH13) stipulates: Sea and island resources consist of living and non-living resources in sea water and seabed, subsoil of seabed, coastal lands and archipelagos, islands, low-tide elevations, shoals in the possession of Vietnam's sovereignty, sovereign rights and jurisdiction [6].
In this legal document, positional resources are understood as the benefits derived from the spatial location of islands and island regions, as well as from their distribution and physical value.These benefits include many closely connected fields with regards to biodiversity, landscape diversity, population distribution, territorial sovereignty, defense, economy, and socio-cultural development.With reference to the content, positional resources can be divided into three different types of resources: geonatural resources, geo-economic resources, and geo-political resources.Each type of resource provides its own unique values and their combination creates an aggregate value for socio-economic development.

Geo-economic position
Key significance for economic development, especially services Local, regional and global A strong impact on the local areas and region

Geo-political position
A special significance with regard to economic benefits and national sovereignty, security and defense Local regional and global Domestic regional relations and regional and international relations Low stability Accordingly, geo-natural resources are the benefits with regard to natural environment stemming from geographical location and region's spatial structure as well as the stability of natural processes and low vulnerability to natural disasters; geo-economic resources are the benefits derived from location and geographical features governing economic development of an area, a country, or even a region, associated with the focal role in economic territorial organization, exchanges and economic relations; geo-political resources are the combined benefits of location advantages and natural and human geographical features of a region or a country which confer politic, military, or diplomatic influences or advantages in a certain politic and economic context [8].

Methods and materials
The materials used for this paper can be divided into three groups: (1) documents, directives, policies, decisions, statistical yearbooks, final reports etc. by Vietnamese government as well as agencies, departments and branches of Ba Ria -Vung Tau province/ Con Dao district relating to Con Dao's potential, position, natural conditions, economic situation, socio-cultural, planning, potential and development direction; (2) published research works (books, journals, theses, dissertations...) by Vietnamese and international scholars with regard to this issue; (3) field survey materials by the author team in Con Dao.
In order to implement this research, we use interdisciplinary/transdisciplinary research methods, such as: (i) Secondary data collection: analysed data are secondary data which have been collected mainly from summary reports, statistical yearbooks, official dispatches, directives and resolutions by Vietnamese government, agencies and departments of Ba Ria -Vung Tau province, Con Dao district, books, scientific articles, scientific journals, theses, dissertations on the websites and other relevant sources.(ii) Field investigation method: field studies were conducted to assess the potential of Con Dao to promote its socio-economic development, in order to provide reasonable and feasible solutions for the future.(iii) Synthetic analysis method: the collected and analysed statistical data is aggregated to generalize and develop a theoretical basis for Con Dao's position potential.The results of the secondary data analysis also serve as concrete proof for general assessments of Con Dao's position potential.This is also the basis for us to give recommendations to upgrade the value and potential of Con Dao's positional resources, with the purpose to serve sustainable socio-economic development in the future.(iv) SWOT analysis method: SWOT analysis was used to analyze and evaluate the strengths, weaknesses, opportunities and challenges in promoting Con Dao's position potential; thereby suggesting possible solutions for the future.

Geo-natural resources
Known as a district-level administrative unit in Ba Ria province -Vung Tau, Vietnam, Con Dao is an archipelago with 16 large and small islands which are off the coast of South Vietnam, with a total area of 76 km 2 , (Con Son is the largest island with total area up to 51.52 km 2 ).Con Dao is about 185 km from Vung Tau city, 230km from Ho Chi Minh City and 83km from the Hau River mouth (Figure 1) [4].Administratively, Con Dao is the only district of Ba Ria -Vung Tau province without a communelevel administrative unit.Under the district level, there are 9 residential areas with a population of more than 12,000 people (in 2022) [9].Con Dao is located at the outermost border adjacent to the territorial sea and exclusive economic zone, opposite Malaysian and Indonesian coasts and islands in the south, 60 km from the international maritime route (North -South axis).The location of Con Dao is a maritime interchange of Vietnam's southern waters.This is the crossroads of international sea routes.With the landmark as Con Dao, the ships can move to North Asia such as Russia, Japan, Korea, Taiwan, Hainan, Shenzhen, Hong Kong.To the south, ships can travel to Southeast Asian countries such as Singapore, Indonesia, Malaysia, Cambodia, Thailand.In the future, when Thailand's KRA canal is opened, connecting the Indian Ocean and the Pacific Ocean to create the East-West axis [11], Con Dao will be located at the crossroads of international maritime traffic.As it is located relatively far from the mainland (about 84 km from the nearest place, Soc Trang province), Con Dao has a potential for expansion in its internal waters, establishment of exclusive economic zones with advantages in defining anti-encroachment zones with neighboring countries on the opposite shore.
Most of Con Dao's land area has a steep mountain topography with a thin effective soil layer.Of the total land area, land with slope over 25% incline accounts for more than 63.6%; land with slope below 15% incline accounts for nearly 13.4%, the rest is land with slope from 15 to 20% incline containing soil layers below and over 50 cm [9].Con Dao's topography is divided into two distinct regions: plains and mountains & forests (mountains and forests account for two-thirds of total area) [4], composed mainly of Cretaceous (70 to 106±4 million years) granite, diorite and rhyolite rocks [8].The low coastal plains with elevation of 4-15 a.s.l occur mostly on main islands; hilly areas occur over all islands and islets with an altitude exceeding 20 m a.s.l.[9].The highest points are the peaks of Thanh Gia Mountain and Chua Mountain, with elevations of 577 m and 515 m, respectively; the highest point on the small islands is 200 m a.s.l.[9].Although there are quite a few islands situated over a fairly wide sea area, Con Dao is considered as being isolated with a unique position, consisting of many high peaks, rocky headlands, cliffs, pools, and beaches favorable for building defense bases and supporting each other in protecting the sea and the archipelago itself.
Located in the tropical monsoon climate, influenced by the sub-oceanic climate, Con Dao's climate is milder than mainland and has two distinct seasons: rainy season (from May to November) and dry season (from December to April).The average temperature is about 26 o C, the average rainfall is 2,575mm [12].Located at the intersection of warm ocean currents from the south and cold currents from the north, the sea water temperature ranges between 25.7 and 29.2 degrees Celsius, which is very suitable for swimming and tourism [8].Con Dao's geographical location and spatial structure reflect its location in the sub-equatorial tropical belt with more favourable climatic conditions in comparison with the north and the central regions both for production and tourism.

Geo-economic resources Con Dao's exceptional position for the development of Vietnam's sea and island economy
Con Dao has always been considered as a key "trade gateway", a suitable area to build trade centers or transshipment warehouses connecting the East and the West.As an archipelago consisting of many small islands in the East Sea and located on the route from the Indian Ocean to the Pacific Ocean, Con Dao has monopolized the intersection position on the maritime route to the world as well within the region: if the ships from China, Tonkin, Macao, Manille, Cochinchina etc, wish to trade with India, it is required for them to come very close to this island; if the British and Dutch ships want to go to the China Sea, they also have to drop off here both waysx.This route is as convenient as the Sonde and Malacca straits.Moreover, Poulo Condoro (ie Con Dao) has the same latitude as Southern Bantam -where the Dutch used to build their trade center [13].Not only dominating international maritime trade, Con Dao's location also connects and shortens the route to Asian countries, specifically: with this island as a landmark, the merchant ships will reach Northeast Asian countries (Japan, Korea, China, and Taiwan) to the north; the and Southeast Asian countries (Singapore, Indonesia, Malaysia,Thailand) tot he south.In the past, Con Dao was both convenient for Westerners to establish trade relations with neighboring countries in Tokin and ideal for them to build military outposts with the purpose of protecting their trading facilities, warehouses and piers [14].
Thanks to the diversity of natural resources, especially forest flora, Con Dao could supply a numerous amount of large-sized woody plants for repair needs of foreign merchant ships in the past.According to "Gia Định thành thông chí" (Gazetteer of Gia Dinh Citadel) by Trinh Hoai Duc, the abundance of Con Dao products is mentioned as follows: "In the middle of the East Sea, from Can Gio port, sailing to the sea in the direction of the east, we will reach the sea after two days.The 100-mile large island has mountain fields growing-rice, corns, potatoes, and beans, but the quantity is not much, so people have to buy rice in Gia Dinh.The local products are horses and buffaloes, the mountains have no tigers.The soldiers often find bird's nest, tortoiseshell, snails, cinnamon incense, fish sauce, cochlea statue, and then offer them according to the season, they also catch seafoods such as fish, shrimp to make a living.The areca nuts are big, the skin is pink, the taste is very sweet and fragrant.When the spring comes, the areca nuts in Gia Dinh are not born fruits, but the areca nuts here have been used and people sell them at a very high price" [15].
Due to the convergence of many available natural advantages (geographical location, climate, water resources, tropical forests, seafood and precious stones), Con Dao has very early become a goods trading address between the traders in the region to China, Dai Viet, Philippines, Malaysia, Thailand; it also provided maritime services for Western merchants.Between late 1600s and early 1800s, the British East India Company and the French East India Company repeatedly sent people to explore Con Dao with the intention of building their own trading system [16].
Due to its position of special importance to national rights and sea benefits, not only in history, but in the present, Con Dao has always been given special attention and priority for development.In September 2011, the Government of Vietnam issued a Decision approving the adjustment of the general construction planning of Con Dao until 2030 (No. 1518/QD-TTg), which clearly stated that the goal is to build Con Dao to ensure a harmonious relationship between development and conservation of historical and cultural relics as well as protection of forest-sea ecosystems consistent with modern and sustainable development.Con Dao will be a modern tourist economic zone of regional and international stature, a conservation area for historical relics, an area for conservation of forest and marine ecosystems of the country, with an extraordinary position in national security and defense [17].On June 17, 2015, the Prime Minister also signed Decision No. 870/QD-TTg approving the "Master plan on development of Con Dao national tourist area, Ba Ria -Vung Tau province to 2030", which clearly defined the objective of "Constructing Con Dao to ensure a harmonious relationship between economic development and conservation of historical and cultural relics, protection of forest-sea ecosystems, ensuring national security and defense towards modern and sustainable development" [18].Thanks to the guidelines and policies of the Government and agencies, a substantial investment has been made in Con Dao in recent years; its infrastructure has been upgraded with regard to road traffic, wharf, airport, power and water supply.

Con Dao's resources attracting investmentment and developmentof marine economic sectors
Forest resources: Con Dao forest stretches from the sea edge to the mountain peaks, mainly in Con Dao National Park.According to land inventory data (as of the end of 2020), total forest area of Con Dao is 6,526.05ha, accounting for 86.1% of Con Dao's natural area; special-use forest covers 5,901.03ha and production forest land covers 625.02 ha [9].Con Dao forest has many ecosystems with very rich flora and fauna, including tropical moist broadleaf forest ecosystem, and forest ecosystem on sand dunes and coastal sandbanks [19].
With regard to the number of species, Con Dao has about 1,077 species of plants, belonging to 640 genera, 160 families of high-level vascular plants in 6 plant branches (table 2).Among the animal species discovered in Con Dao, there are 31 rare species (accounting for 19.38% of total number of discovered animal species), including: 11 species of mammals, 8 species of birds and 12 species of reptiles.There are especially rare species such as: Callosciurus, Ratufa bicolor condorensis, Nicobar (Caloenas nicobarica), Ducula bicolor or Sula leucogaster which are endemic to Con Dao in the territory of Vietnam [20].
Marine biological resources: Con Dao waters are tropical marine ecosystems; therefore, they are very diverse and rich in quantity and reserve of marine species [21].According to Nha Trang Institute of Oceanography, Con Dao waters are the richest in density and own the most abundant marine species in Vietnam.There are 1,725 marine species, of which there are 46 species of mangroves, 133 species of seaweed, 11 species of seagrasses, 226 species of phytoplankton, 143 species of zooplankton, 360 species of coral, 130 species of polychaetes, 116 species of crustaceans, 187 species of mollusks, 115 species of echinoderms, 205 species of coral reef fish, 9 species of marine reptiles, 37 species of seabirds and 7 species of marine mammals [22].Furthermore, Con Dao waters are also a habitat for marine mammals and reptiles such as: Stenella longirostris, Balaenoptera musculus, Dugong dugon (also known as Seacow), Microthele nobilis and many rare mammals occure near the shore such as: Callosciunis finlaysoni, Ratufa bicolor condorensis, Rattus niviventer condorensis or Cyrstodactylus condorensis [23].In addition, there are marine reptiles, including sea turtles and sea snakes; Con Dao is the major location for sea turtles nesting in Vietnam, with 90% of species nesting here.There are 16 sandy beaches where sea turtles lay their eggs every year [23].Thanks to the success of sea turtle conservation in recent years, Con Dao has become an area of international significance in global sea turtle conservation efforts.Con Dao National Park is the first unit in Vietnam to become a member of the network the Indian Ocean -South -East Asian (IOSEA) Marine Turtle, as the 11th organization of this network on October 22, 2019 [22].
Con Dao marine ecosystem is a habitat for 7 critically endangered species, 67 endangered and threatened species (according to the Vietnam Red Book, 2007) and over 300 species of hard corals on the CITES list.The critically endangered species (CR) are: Tectusniloticus, Charonia and Charonia tritonis, Cypraea argus, Nautilus pompilius, Bostrichthys sinensis, Dugong dugon [22].The structure of marine ecosystem in many areas such as the Northeast Bay and the Northwest of Con Son Island (from Tre Lon island to Viet Minh cape) is still relatively intact with a relatively high value for economy, tourism and science [24].According to statistics, the ecological system in Con Dao with three main ecological forms of mangrove, seagrass and coral reef ecosystems has a high biological value it is attractive and less affected by humans [23].
The mangrove ecosystem in Con Dao has a small area (over 32 hectares); however, it is still primitive, unaffected by humans and typical for the type of mangroves occuring on dead coral, sand and gravel sediment [25].Forty-six mangrove plant species have been discovered in Con Dao, the dominant species are Rhizophora apiculata, Bruguiera gymnorrhiza, Rhizophora mucronata.Among 46 discovered species, three are listed in Vietnam Red Book (Rhizophora apiculata Blume, Lumnitzera littorea (Jack) and Dolichandrone spathacea).Mangrove forests are also nurseries of marine fish species and a unique landscape for visitors [24].The seagrass ecosystem in Con Dao is very rich.Survey and research in Con Dao waters revealed the occurrence of 11 species of seagrass -out of 13 currently known seagrass species in Vietnam.The existence and development of the seagrass ecosystem plays an extraordinary role as the main food source of Dugong dugon, a rare marine mammal [22].Coral ecosystem in Con Dao is established in the area surrounding the islands;, many coral reefs are still highly primitive.There are 360 species, 61 varieties, 17 families of coral here [22].Coral reefs in Con Dao occur mostly in the shallow water around the islands to a depth of approx 20m and cover a total area estimated at 1,000ha [8].The reef is a residence of 1,323 species of marine flora and fauna and 153 species of krill which are classified under the first and second level of Vietnam's list of endangered species [26].Species composition of Con Dao coral system is rich and diverse so Con Dao is a primary location for breeding, egg-laying, larval rearing and feeding for many marine species of the southeast Vietnam marine area and the entire Southeast Asia region; furthermore, it is also extraordinary in regulating and balancing the amount of oxygen in sea water and protecting the coast of Con Dao [26].Natural Tourism Resources: Being the archipelago with an extraordinary role and position of Ba Ria-Vung Tau province in particular as well as of Vietnam in general, Con Dao is a famous tourist destination, which is identified as one of 49 potential areas to develop into a national tourist area of Vietnam [27].Con Dao is voted by many prestigious magazines as one of the islands with the most pristine, mysterious and beautiful scenery in the world: "the place with steep cliffs next to pristine beaches and clear blue water; a natural paradise with dense forests, turquoise waters, white sands and a home of Dugong dugon, dolphins, sea turtles and spectacular coral reefs…" [28].Lonely Planet magazine ranked Con Dao in the list of the world's best and mysterious islands -a natural paradise with dense forests, jade-colored waters, white sands and a home of Dugong dugon, dolphins, sea turtles and reefs [29].
Con Dao consists of 16 islands, of which 14 are clustered closely together with 200 km of coastline, including beautiful beaches with wild features such as: Dam Trau, Vong beach, Nhat beach, An Hai beach which are ranked as the best quality beaches of the country [25].Con Dao waters are included in the list of "Zones with the highest priority for protection" in the system of marine protected areas of the World Bank, having the highest density and abundance of species in Vietnam; many coral reefs are still highly primitive [30].In recent marine surveys, the experts have found new species for the world and Vietnam [31].Con Dao also has a national park with a system of special-use forests with a total natural area of more than 19,883 hectares.Currently, Con Dao National Park has 4 ecosystems: forest ecosystem on low hills, forest ecosystem on sand dunes and coastal sandy beaches, mangrove ecosystem and alum flooded forest ecosystem [32].Particularly, Con Dao Sea has three main ecosystems, which are mangrove, seagrass and coral ecosystems [31].The endemic, precious and rare flora and fauna typical for these ecosystems, as well as the hot and humid sub-equatorial-oceanic climate conditions are very favorable for the development of resort tourism [12], which has become the potential for investment and development of ecotourism products at national and international levels, attracting domestic and foreign tourists.
Con Dao, a blue archipelago in the middle of the East Sea, is a green tourist paradise with white sand beaches, clear blue sea, primeval forests, golden sand beaches surrounded by many small islands; in addition to the oceanic climate, it creates a fresh, airy environment and beautiful beaches with many unique landscape values [33].In particular, Con Dao's natural heritage also includes many unique values.Con Dao is one of the few places in Vietnam with both forests and the sea; therefore, the biodiversity of Con Dao's nature is also the biodiversity of flora and fauna in forest (precious wood, animals, rare forests), and marine biodiversity (mangroves, coral reefs, seagrass beds, diverse marine species, including those listed in the Red List) [34].Two main landscape types of Con Dao are: (i) mainland landscape on the island with hills, steep cliffs and large primeval forest areas (ii) rich and diverse marine landscape typically in shallow water areas around islands where coral reefs, seagrass beds and mangroves are found [35].
Cultural and historical tourism resources: Con Dao has been a "sacred strip of land" for a long time, a place to mark and remember Vietnamese prisoners -revolutionary soldiers [36].During the two resistance wars against the French and against the US, Con Dao was known as "hell on Earth", where the French and the Americans established a prison system for Vietnam's revolution soldiers.At present, there is Con Dao special National Historic Site with many typical cultural and historical relics such as: Con Dao Prison System, Hang Duong Cemetery, Hang Keo Cemetery, Pier; and other cultural relics such as Cong Quan House, Ba Phi Yen Temple, Cau Temple, Nui Mot Pagoda which have many cultural and historical values for tourism development.In particular, Con Dao revolutionary historical relic (including the Con Dao prison system and the cemeteries of the prison system) has been recognized as a special national relic site, attracting many Vietnamese and international tourists to come here to visit and study.
Tourism development infrastructure: in addition to natural landscape and historical and cultural resources, considerable investments have been made in Con Dao district's infrastructure in recent years to serve tourism development so that it becomes a key economic sector.According to 2022 statistic data, there are 142 business establishments in Con Dao, with a total of 2,689 rooms, accommodating 6,976 people/day; there are 98 restaurants and eateries in operation as well as 41 gift and souvenir establishments.Currently, Con Dao has about 17 companies operating in the fields of travel, diving and water sports.The road traffic system in Con Dao is also well developed with total road length of 78.32km [35].The island can be reached by air and water.Con Dao airport is 3C airport (according to ICAO), the infrastructure of the airport is adequate to accommodate ATR-72 aircraft and equivalent.Currently, there are three passenger airlines operating between the mainland and Con Dao, including Vietnam Airlines, Bamboo Airways and helicopters.Currently three companies are transporting passengers to Con Dao by water [35].Telecommunications infrastructure in Con Dao is also increasingly developed with efficient internet, television, communication, express delivery and phone networks [37].With the aim of turning Con Dao into a high-quality tourist-service area, the Government of Vietnam approved a number of preferential mechanisms and policies for Con Dao that have been in effect since 2013; These aimed to facilitate quick procedures for investment and business; introduce corporate income tax incentives (the tax rate is reduced to 10% and the incentive period can be up to 30 years); reduce 50% of personal income tax; exempt from import tax and apply value added tax of 0% for capital construction investment expenses [38].In the master plan for the development of Con Dao National Tourism Area to 2020 with a vision to 2030, Con Dao prioritizes the development of various types of eco-tourism, high-class resort, culture-history-spirituality tourism, and it requires connection with the international market and improvement in competitiveness with tourism on other islands in the country and abroad.

Geo-politic resources
Con Dao posesses an extraordinary strategic position with regard to national defense and security, as it is located in the East Sea at the crossroads of international sea routes, the intersection point of two maritime routes from the South to the North of Asia and the maritime route from West to East and vice versa; it is also Vietnam's gateway to ASEAN countries.Therefore, Con Dao has always had an extraordinary geopolitical position, not only for Vietnam but also for many countries in the region and the world .
Due to its location in the Eurasian maritime route, connecting the Pacific Ocean with the Indian Ocean, Con Dao had very early become of interest and known to Western expeditions.In 1292, an Italian explorer Marco Polo, on his way back from China to Europe, set foot in this area and reported the existence of Con Dao as a "stop on the route from the North to the South, from the East to the West" [39].In 1516, a Portuguese navigator -Fernão Perès de Andrade came to Con Dao and reported that European sailors were frequently present here to get fresh water, look for sea turtles and pick wild grapes [16].In the mid 1560s., the geo-politic position of Con Dao was recorded by poet Luís Vaz de Camões in the manuscript of his history book "Os Lusiadas" when his Portuguese expedition visited this area [40].All records and assessments of Westerners showed the natural features and extraordinary geopolitical position of Con Dao at that time.
As described by many researchers, Con Dao has not only held the role of a trade gateway since the medieval period, but was also known as an extraordinary military outpost.The unique geo-political factor of this archipelago was evident: with the interwoven and completely closed system of mountains and forests it played a strategic role for building citadels, ramparts and setting up military obstacles to actively attack or proactively defend by surprise.In addition, the diversity of terrain also creates favorable conditions for the construction of fortresses, guard posts, and observation posts, as a consequence forming a multi-layered military fence both onshore and underwater.Furthermore, with the advantage of being an archipelago with many small islands, Con Dao is quite similar to military bases floating above the water, creating a continuous position in the arrangement of firepower [41].In discussion of the favorable political and military terrain of Con Dao, in 1687, the British explorer, William Dampier, commented that the island's location is very convenient for travels to and from Japan and China, Manila, Tonkin, Cochinchina as well as all areas on the easternmost coast of the Indian mainland, whether passing through Malacca Bay or Sunda Bay between Sumatra and Java [42].Meanwhile, within Asia, the voyages from India to China at that time had to go through Con Dao as the gateway to Chenla, Champa, Dai Viet [43].The above advantages show that once a military base is established in Con Dao, the navies of countries can both control the arterial sea route and master the gateway to Southeast Asia.
IOP Publishing doi:10.1088/1755-1315/1247/1/01201411 Due to this particular advantage, between the late 1600s and 1800s, Western countries identified Con Dao as the most ideal location to act as a springboard to invade Asian countries.In the archipelago, it is possible to monitor and control the activities of ships on a large scale, and Con Dao can completely be built to become a large and strong military base for sea control and direct protection of Tu Chinh, Huyen Tran and Vung May beaches in the Southeast sea of Vietnam [44].Therefore, between the 17th and 19th centuries, both Britain and France competed to monopolize Con Dao in order to gain economic and political advantages in the strategy of expanding the sphere of influence outside of Europe.In 1702, East India Company landed on Con Dao, deployed to build a flagpole and fortress to assert its sovereignty [16], but then Lord Nguyen recaptured this archipelago.However, in 1771, the Nguyen Dynasty faced difficulties in the country due to the uprising of Tay Son farmers, so they had to flee to Con Dao and ask for French help.In 1787, the Treaty of Versailles was signed by the Nguyen Dynasty with the Count De Mantmarin (representing King Louis XVI of France).According to the content of the Treaty, the Nguyen Dynasty ceded to France the sovereignty of the seaport of Da Nang and Con Lon Islands (ie Con Dao) [45].After capturing Con Dao, with an extraordinary geopolitical position, in 1862, France signed a decision to establish Con Dao prison.From that time until 1954, Con Dao officially became the "hell on Earth" to Vietnamese patriots and a model prison in the French colonial prison system in Vietnam and abroad.In 1954, when the US replaced France in Vietnam, the strategic geographical position of Con Dao was still requisitioned by this superpower for the purpose of detaining Vietnamese Revolutionary soldiers.Accordingly, Con Dao continued to become a typical prison in the American imperial prison system in South Vietnam until the twentieth century.Obviously, the fact that Con Dao was peeped and invaded by Western countries very early on has shown the stupendous military and economic value of the geo-politic positional resources of this archipelago in the strategy of "colonial" regime in the whole Indochinese peninsula.
With regard to national security and territorial benefits, Con Dao is located at the outermost border adjacent to the territorial sea and exclusive economic zone, opposite to the coasts and islands of Malaysia and Indonesia to the South.In the guard position of the archipelago, its first function is to protect the South East's sovereign waters, adjacent to Tu Chinh -Huyen Tran waters of Vietnam, so as to protect the southern mainland and create conditions for developing international maritime trade and services [8].In addition, Con Dao has a great potential in Vietnam's maritime territory.This archipelago has three islands (Tai Lon, Bong Lang, Bay Canh) which have been selected as the benchmarks to establish a straight baseline to calculate the breadth of territorial sea; it has created a large internal water area, including the entire Cuu Long oil and gas basin, and the territory of Vietnam is extended hundreds of kilometers to the sea [46].Con Dao is increasingly appreciated for its extraordinary position for construction and national defense of Vietnam, because it is possible to establish bases to control the sea and airspace from Con Dao, contributing to ensure security in Vietnam's waters.Furthermore, it is "to check the operation of ships and boats, ensuring security and defense, building the economy, protecting sovereignty and integrity of Vietnam" [47].

Future directions for the development of Con Dao based on positional resources
Positional resources are the values and benefits obtained by using the location and space of a place for socio-economic development, defense and other national benefits.Therefore, the assessment of this resource requires a different approach from that of the analysis of other resources.Each area or object with positional resource value is a system or a part of a natural -economic -social system with associated values.The use of positional resources of sea and islands in sustainable development will ensure three benefits in terms of economy (service is the focus), society (sovereignty and national benefits are the focus) and environment (natural conservation is the focus).
As an offshore archipelago, Con Dao is located at the crossroads of international sea routes, the intersection point of two maritime routes from the South to the North of Asia and the maritime route from the West to the East and vice versa, as a gateway of Vietnam with ASEAN countries; an area with an extraordinary strategic position with regard to national defense and security, located in the Southeast sea of Vietnam.Con Dao has a great potential and strengths for nature conservation and tourism development, seafood exploitation and processing, seaport development, petroleum and maritime services.It also plays an extraordinary role in providing marine breeding resources for the South Central Coast, the Southeast and the Gulf of Thailand [48].In addition, Con Dao environmental conditions are optimal for the development of sea swimming and resort tourism, eco-tourism (diving, fishing, climbing, visiting marine forests and sea animals), geological tourism with many geological formations of heritage value, and historical tourism; moreover, it is the center of fishing grounds for seafood exploitation in the South.In the future, Con Dao will be located at the crossroads of international maritime traffic when Thailand's KRA canal opens to the Indian Ocean and the Pacific Ocean [49].With its geographical location and rich and diverse natural resources, the Government of Vietnam in general and Ba Ria Vung Tau province in particular have issued many guidelines and policies for the integrated management of the island cluster's resources in order to develop sustainably Con Dao economy while ensuring sovereignty over the sea and islands.In practice, a lot has been achieved but there are also many difficulties and challenges.In order to facilitate development and progress based on the resources and position of Con Dao in the near future, in our opinion, it is necessary to take a number of following measures.
First, promoting Con Dao's positional resource potential is required to meet the long-term needs for sustainable socio-economic development; contribute to ensuring security, national defense, sovereignty and sea benefits; integrate rational use of marine space with economic services as the focus, with environmental protection, nature conservation and promotion of cultural, scientific and educational values [50].Therefore, it is necessary to soon develop a long-term oriented strategy and an immediate plan to rationally use the resources and position of Con Dao in the direction of sustainable development and create the possibility of socio-economic breakthroughs with service economy being the focus.Furthermore, it is necessary to continuously build and complete the institutional and policy basis and supplement the legal documents relating to the development of marine and island space in general and Con Dao in particular.In addition to creating an equal competitive environment, the state retains the rights to operate and manage in a number of key fields of resource exploitation and marine economic development [51].
Second, socio-political stability plays a fundamental role in exploiting status resources.Therefore, it is necessary to strengthen security -defense, combat piracy and illegal resource exploitation to protect and sustainably develop marine resources by both marine and remote sensing means [52].Concentrating resources to build and strengthen national defense -people's security, closely combine national defense with economy and vice versa, maintain sovereignty and security of sea and island borders.As a consequence, proposing and developing specific regulations on limiting the scope of fishing to protect coastal and island aquatic resources.Speeding up the promotion, implementation and preparation of sectoral plans on socio-economic development related to the sea such as: Ben Dam industrial cluster planning, fisheries sector planning, etc [50].
Third, it is necessary to step up investigation and assessment to understand the nature, value and potential of the resources and position of Con Dao, including the sea, coastal areas and islands.It is also of importance to prioritize construction of works on the sea, forecast and exploration of minerals and fishery resources, high-productivity aquaculture, freshwater for coastal areas and offshore islands, development of clean energy sources with origin from the sea (wind, waves, tides, ocean currents...) [53].However, strengthening capacity development of scientific staff and experts for marine space research and management is needed for optimal organization of the implementation of policies and regimes of the Central Government and of Ba Ria -Vung Tau province, especially with regard to attracting and training sea-related professionals in the fields of tourism services, fishing and aquaculture, marine resource protection, marine and island fisheries protection, oil and gas services, port services, sea transportation.This can be achieved on the basis of cooperation with training institutions inside and outside the province; at the same time, there is a policy to encourage students to register for the above- Fourth, it is required to have a flexible view of geo-politic and geo-economic values, because the geo-politic and geo-economic characteristics of each locality, region or country will change according to the level of development and general national, regional and global contexts [55].Moreover, the influence sphere of geo-politics and geo-economy tends to embrace growing exchanges, cooperation and globalization.While local and regional benefits are associated with national benefits, national benefits are increasingly intertwined with regional and international benefits.It is thus key to strenghten international integration to create opportunities for understanding and learning from the world's experiences in rational use of resources and the position of sea and islands.It is also necessary to advocate international cooperation in the context of globalization to integrate and implement the marinespace related conventions signed by Vietnam.Forms of international cooperation should be expanded in information materials, training, seminars, exchange visits, participation in regional or bilaterally or multilaterally coordinated global programs and projects.Participation in international organizations and network activities on maritime position and space is also recommended [50].

Conclusion
Positional resources are the values and benefits obtained by using the location and space of a place for the purposes of socio-economic development, defense and other national benefits.Currently, Vietnam is accelerating the process of industrialization and modernization of the country and especially the development of a market economy based on a service economy, therefore, it requires an advance in using the position potential of sea and islands.
Con Dao has been known to the world from the earliest times of geographic explorations.Both in the past and at present, Con Dao holds special advantages for the development and tenhancement of the international reputation of the archipelago itself as well as Vietnam in general.Con Dao has an impressive potential, in which geo-political positional resources play an extraordinary role with the values of expanding sovereignty, ensuring national sea benefits and a solid defense and effective surveillance of a vast sea.The extraordinary geo-politic value stems from the the geo-natural position of this archipelago.Currently, Con Dao focuses on tourism development as the only key economic sector with a system of national historical relics (especially Con Dao Prison) internationally recognized Ramsar area, ; rich ecosystems thanks to conservation and protection, and well-developed infrastructure basically meeting the needs of tourists.Main products of Con Dao tourism are historical and spiritual relics combined with eco-tourism including sightseeing, culinary tourism, exploration of local products and traditions (such as pearl culture village, or making acacia nut jam).However, supporting Con Dao's position potential and its sustainable development is still one of the major challenges that requires the attention, investment and enthusiasm of the State management agencies, departments and local authorities.It also requires strategies to protect the natural landscape, biodiversity, maintain the historical -cultural values of the nation, further economic development and improve the lives of island people.

Figure 2 .
Figure 2. Map of Con Dao Islands was drawn by two engineers Deidier and Verrier in 1721 and published by Souciet in 1729 domestic and foreign institutions with policies on post-training use and tuition support [54].

Table 1 :
Components of positional resources and their importance[7]

Table 2 :
Flora of Con Dao [20]With regard to animals, terrestrial vertebrate fauna of Con Dao National Park includes 155 species of animals belonging to 64 families, 26 sets consisting of 25 species of mammals, 85 species of birds, 32 species of reptiles and 13 species of amphibians (table 3) [9].