Added CRS indexing based on an sqlite database

ProjNet4GeoAPI.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.0.29020.237
+# Visual Studio Version 17
+VisualStudioVersion = 17.4.33103.184
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ProjNET", "src\ProjNet\ProjNET.csproj", "{E028BDD2-55E1-4E5F-BE31-35FAEC8D6428}"
 EndProject
@@ -15,6 +15,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ProjNET.Tests", "test\ProjN
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ProjNet.Benchmark", "src\ProjNet.Benchmark\ProjNet.Benchmark.csproj", "{1E5D1CC5-8CFE-4C9D-9553-900469C57D6C}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ProjNet.Sqlite", "src\ProjNet.Sqlite\ProjNet.Sqlite.csproj", "{3D364E7E-7D2D-42FB-A62B-137BBA2F8F1E}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -33,6 +35,10 @@ Global
 		{1E5D1CC5-8CFE-4C9D-9553-900469C57D6C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{1E5D1CC5-8CFE-4C9D-9553-900469C57D6C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{1E5D1CC5-8CFE-4C9D-9553-900469C57D6C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3D364E7E-7D2D-42FB-A62B-137BBA2F8F1E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3D364E7E-7D2D-42FB-A62B-137BBA2F8F1E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3D364E7E-7D2D-42FB-A62B-137BBA2F8F1E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3D364E7E-7D2D-42FB-A62B-137BBA2F8F1E}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/ProjNet.Sqlite/CoordinateSystemInfo.cs

@@ -0,0 +1,66 @@
+using SQLite;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ProjNet.IO
+{
+    /// <summary>
+    /// Model for coordinate system in the database
+    /// </summary>
+    [Table("srs_data")]
+    public class CoordinateSystemInfo
+    {
+        /// <summary>
+        /// 
+        /// </summary>
+        public string Authority { get; set; }
+        /// <summary>
+        /// 
+        /// </summary>
+        [PrimaryKey]
+        public int Code { get; set; }
+        /// <summary>
+        /// 
+        /// </summary>
+        public string Name { get; set; }
+        /// <summary>
+        /// 
+        /// </summary>
+        public string Alias { get; set; }
+        /// <summary>
+        /// 
+        /// </summary>
+        public bool IsDeprecated { get; set; }
+        /// <summary>
+        /// 
+        /// </summary>
+        [Column("type")]
+        public string SystemType { get; set; }
+        /// <summary>
+        /// 
+        /// </summary>
+        public string WKT { get; set; }
+
+        /// <summary>
+        /// Parameterless construction for initialization
+        /// </summary>
+        public CoordinateSystemInfo()
+        {
+        }
+
+        /// <summary>
+        /// Holds info about the coordinate system
+        /// </summary>
+        public CoordinateSystemInfo(string name, string alias, string authority, int code, string systemType, bool isDeprecated, string wkt)
+        {
+            Authority = authority;
+            Code = code;
+            Name = name;
+            Alias = alias;
+            SystemType = systemType;
+            IsDeprecated = isDeprecated;
+            WKT = wkt;
+        }
+    }
+}

src/ProjNet.Sqlite/DatabaseCoordinateService.cs

@@ -0,0 +1,148 @@
+using ProjNet.CoordinateSystems;
+using ProjNet.IO;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ProjNet.Services
+{
+    /// <summary>
+    /// Coordinate System Service tied to a database
+    /// </summary>
+    public class DatabaseCoordinateService : CoordinateSystemService, ICoordinateSystemService
+    {
+        private readonly DatabaseProvider _dbProvider;
+
+        /// <summary>
+        /// Initializes a DatabaseCoordinateService to retreive 
+        /// Coordinate Systems from an internal database
+        /// </summary>
+        public DatabaseCoordinateService(CoordinateSystemFactory csFactory)
+            : base(csFactory)
+        {
+            _dbProvider = new DatabaseProvider();
+        }
+
+        /// <summary>
+        /// Initializes a DatabaseCoordinateService to retreive 
+        /// Coordinate Systems from an internal database
+        /// </summary>
+        public DatabaseCoordinateService()
+            : this(new CoordinateSystemFactory())
+        {
+            _dbProvider = new DatabaseProvider();
+        }
+
+        #region Interface Methods
+        /// <summary>
+        /// Returns the coordinate system by <paramref name="srid" /> identifier
+        /// </summary>
+        /// <param name="srid">The initialization for the coordinate system</param>
+        /// <returns>The coordinate system.</returns>
+        public CoordinateSystem GetCoordinateSystem(int srid)
+        {
+            var sysInfo = _dbProvider.GetCoordinateSystemInfo(srid).Result;
+            if (sysInfo != null)
+                return CsFactory.CreateFromWkt(sysInfo.WKT);
+
+            return null;
+        }
+
+        /// <summary>
+        /// Returns the coordinate system by <paramref name="srid" /> identifier
+        /// </summary>
+        /// <param name="srid">The initialization for the coordinate system</param>
+        /// <returns>The coordinate system.</returns>
+        public async Task<CoordinateSystem> GetCoordinateSystemAsync(int srid)
+        {
+            var sysInfo = await _dbProvider.GetCoordinateSystemInfo(srid);
+            if (sysInfo != null)
+                return CsFactory.CreateFromWkt(sysInfo.WKT);
+
+            return null;
+        }
+
+        /// <summary>
+        /// Returns the coordinate system by <paramref name="authority" /> and <paramref name="code" />.
+        /// </summary>
+        /// <param name="authority">The authority for the coordinate system</param>
+        /// <param name="code">The code assigned to the coordinate system by <paramref name="authority" />.</param>
+        /// <returns>The coordinate system.</returns>
+        public CoordinateSystem GetCoordinateSystem(string authority, long code)
+        {
+
+            int? srid = GetSRID(authority, code);
+            if (srid.HasValue)
+                return GetCoordinateSystem(srid.Value);
+            return null;
+        }
+
+        /// <summary>
+        /// Searches the table names based on an expression
+        /// </summary>
+        /// <param name="name"></param>
+        public Task<IEnumerable<CoordinateSystemInfo>> SearchCoordinateSystemAsync(string name)
+        {
+            return _dbProvider.SearchCoordinateSystemAsync(name);
+
+        }
+
+        /// <summary>
+        /// Method to get the identifier, by which this coordinate system can be accessed.
+        /// </summary>
+        /// <param name="authority">The authority name</param>
+        /// <param name="authorityCode">The code assigned by <paramref name="authority" /></param>
+        /// <returns>The identifier or <value>null</value></returns>
+        public int? GetSRID(string authority, long authorityCode)
+        {
+            return (int)authorityCode;
+        }
+
+        /// <summary>
+        /// Returns number of coordinate systems registered by the service
+        /// </summary>
+        public int Count => _dbProvider.GetCount().Result;
+
+        /// <summary>
+        /// Adds a coordinate system to the dictionary based on srid
+        /// </summary>
+        /// <param name="srid"></param>
+        /// <param name="coordinateSystem"></param>
+        public void AddCoordinateSystem(int srid, CoordinateSystem coordinateSystem)
+        {
+            if (coordinateSystem.Name == null)
+                throw new ArgumentNullException("Name is null.");
+            if (coordinateSystem.AuthorityCode <= 0)
+                coordinateSystem.AuthorityCode = srid;
+            if (string.IsNullOrEmpty(coordinateSystem.Authority))
+                coordinateSystem.Authority = "EPSG";
+            if (string.IsNullOrEmpty(coordinateSystem.Alias))
+                coordinateSystem.Alias = coordinateSystem.Name;
+
+            AddCoordinateSystem(coordinateSystem);
+        }
+
+        /// <summary>
+        /// Adds a coordinate system to the dictionary.
+        /// The authority code is defaulted as the srid.
+        /// </summary>
+        /// <param name="coordinateSystem"></param>
+        /// <returns></returns>
+        public int AddCoordinateSystem(CoordinateSystem coordinateSystem)
+        {
+            return _dbProvider.AddCoordinateSystem(coordinateSystem).Result;
+        }
+
+        /// <summary>
+        /// Removes a coordinate system from the database
+        /// </summary>
+        public bool RemoveCoordinateSystem(int srid)
+        {
+            return _dbProvider.RemoveCoordinateSystem(srid).Result;
+        }
+        #endregion
+    }
+}

src/ProjNet.Sqlite/DatabaseProvider.cs

@@ -0,0 +1,151 @@
+using ProjNet.CoordinateSystems;
+using ProjNet.IO.CoordinateSystems;
+using ProjNet.Sqlite.Extensions;
+using SQLite;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace ProjNet.IO
+{
+    /// <summary>
+    /// Handles calls to the database
+    /// </summary>
+    public class DatabaseProvider
+    {
+        private string _connectionString;
+        SQLiteAsyncConnection Database;
+
+        /// <summary>
+        /// Creates an instance of the DatabaseProvider
+        /// </summary>
+        public DatabaseProvider()
+        {
+            string currentDir = AppContext.BaseDirectory;
+            _connectionString = Path.Combine(currentDir, "proj.db");
+        }
+
+        /// <summary>
+        /// Creates an instance of the DatabaseProvider
+        /// </summary>
+        public DatabaseProvider(string database)
+        {
+            _connectionString = database;
+        }
+
+        /// <summary>
+        /// Initializes the Database 
+        /// </summary>
+        /// <returns></returns>
+        async Task Init()
+        {
+            if (Database is not null)
+                return;
+
+            Database = new SQLiteAsyncConnection(_connectionString, SQLiteOpenFlags.ReadWrite | SQLiteOpenFlags.SharedCache);
+            var result = await Database.CreateTableAsync<CoordinateSystemInfo>();
+        }
+
+        /// <summary>
+        /// Returns the coordinate info base on the code
+        /// </summary>
+        /// <param name="srid">the code to retrieve</param>
+        public async Task<CoordinateSystemInfo> GetCoordinateSystemInfo(int srid)
+        {
+            await Init();
+            return await Database.Table<CoordinateSystemInfo>().Where(i => i.Code == srid).FirstOrDefaultAsync();
+        }
+
+        /// <summary>
+        /// Searches the table names based on an expression
+        /// </summary>
+        /// <param name="searchKey"></param>
+        public async Task<IEnumerable<CoordinateSystemInfo>> SearchCoordinateSystemAsync(string searchKey)
+        {
+            await Init();
+            var filters = searchKey.ToLower().Split(' ').ToList();
+
+            return await Like(filters);
+       }
+
+        private async Task<IEnumerable<CoordinateSystemInfo>> Like(List<string> filters)
+        {
+            var data =await Database.Table<CoordinateSystemInfo>().ToArrayAsync();
+            foreach (string filter in filters)
+                data = data.Where(x => x.Name.ToLower().Contains(filter)).ToArray();
+
+            return data;
+        }
+
+            /// <summary>
+            /// Returns the number of entries in the database
+            /// </summary>
+            internal async Task<int> GetCount()
+        {
+            await Init();
+            return await Database.Table<CoordinateSystemInfo>().CountAsync();
+        }
+
+        /// <summary>
+        /// Adds a coordinate system to the database
+        /// </summary>
+        internal async Task<int> AddCoordinateSystem(CoordinateSystem coordinateSystem)
+        {
+            var coordType = GetSystemType(coordinateSystem.WKT);
+            var coordInfo = new CoordinateSystemInfo(coordinateSystem.Name, coordinateSystem.Alias,
+                coordinateSystem.Authority, (int)coordinateSystem.AuthorityCode,
+                coordType.ToString(), false, coordinateSystem.WKT);
+
+            return await AddCoordinateSystem(coordInfo);
+        }
+
+        internal async Task<int> AddCoordinateSystem(CoordinateSystemInfo coordinateInfo)
+        {
+            await Init();
+            return await Database.InsertAsync(coordinateInfo);
+        }
+
+        /// <summary>
+        /// Removes a coordninate system from the database
+        /// </summary>
+
+        internal async Task<bool> RemoveCoordinateSystem(int srid)
+        {
+            await Init();
+            var csInfo = await GetCoordinateSystemInfo(srid);
+            if (csInfo != null)
+                return await Database.DeleteAsync(csInfo) > 0;
+
+            return false;
+        }
+
+        /// <summary>
+        /// Parses the wkt to get the appropriate CoordinateSystemType
+        /// </summary>
+        private CoordinateSystemType GetSystemType(string wkt)
+        {
+            int bracket = wkt.IndexOf("[");
+            if (bracket >= 0)
+            {
+                string coordType = wkt.Substring(0, bracket);
+                switch (coordType)
+                {
+                    case "PROJCS":
+                        return CoordinateSystemType.projected;
+                    case "GEOGCS":
+                        return CoordinateSystemType.geographic2D;
+                    case "COMPD_CS":
+                        return CoordinateSystemType.compound;
+                    case "VERT_CS":
+                        return CoordinateSystemType.vertical;
+                }
+            }
+
+            return CoordinateSystemType.unknown;
+        }
+
+
+    }
+}