Add Known limitations section to README (#23)

* Add Known limitations section to README

* Validity
* Fullglobe
* Measures

* Fix typo

* Fix gh version suffix in Directory.Build.props

NetTopologySuite.IO.SqlServerBytes.sln

@@ -1,20 +1,24 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 15
-VisualStudioVersion = 15.0.26124.0
+# Visual Studio Version 17
+VisualStudioVersion = 17.0.32112.339
 MinimumVisualStudioVersion = 15.0.26124.0
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NetTopologySuite.IO.SqlServerBytes", "src\NetTopologySuite.IO.SqlServerBytes\NetTopologySuite.IO.SqlServerBytes.csproj", "{0402AAFA-DC37-4844-97E2-6205C5BE8882}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "NetTopologySuite.IO.SqlServerBytes", "src\NetTopologySuite.IO.SqlServerBytes\NetTopologySuite.IO.SqlServerBytes.csproj", "{0402AAFA-DC37-4844-97E2-6205C5BE8882}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NetTopologySuite.IO.SqlServerBytes.Test", "test\NetTopologySuite.IO.SqlServerBytes.Test\NetTopologySuite.IO.SqlServerBytes.Test.csproj", "{D793B2F0-9612-4511-8932-D0D2028691AA}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "NetTopologySuite.IO.SqlServerBytes.Test", "test\NetTopologySuite.IO.SqlServerBytes.Test\NetTopologySuite.IO.SqlServerBytes.Test.csproj", "{D793B2F0-9612-4511-8932-D0D2028691AA}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Items", "Items", "{6A5A94FB-AA3A-4EE4-ADBC-F9DF7D9829E5}"
+	ProjectSection(SolutionItems) = preProject
+		src\Directory.Build.props = src\Directory.Build.props
+		.github\workflows\dotnet.yml = .github\workflows\dotnet.yml
+		README.md = README.md
+	EndProjectSection
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
 		Release|Any CPU = Release|Any CPU
 	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
-		HideSolutionNode = FALSE
-	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
 		{0402AAFA-DC37-4844-97E2-6205C5BE8882}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{0402AAFA-DC37-4844-97E2-6205C5BE8882}.Debug|Any CPU.Build.0 = Debug|Any CPU
@@ -25,4 +29,10 @@ Global
 		{D793B2F0-9612-4511-8932-D0D2028691AA}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{D793B2F0-9612-4511-8932-D0D2028691AA}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {00C34697-7D1D-4794-B3A0-7DE54D6654C5}
+	EndGlobalSection
 EndGlobal

README.md

@@ -30,3 +30,28 @@ var parameter = command.Parameters
 //parameter.SqlDbType = SqlDbType.Udt;
 //parameter.UdtTypeName = "geography";
 ```
+
+## Known limitations
+### Validity
+SqlServer and NetTopologySuite have a slightly different notion of a geometry's validity. SqlServer stores this
+information along with the geometry data and the `SqlServerBytesWriter` uses NetTopologySuite's `Geometry.IsValid` value.
+You might get SqlServer geometries that return `STIsValid() = true` but `STIsValidReason() = false`.
+
+### Fullglobe 
+SqlServer geography types include `FULLGLOBE`, basically a polygon where the globe is the outer ring (shell)
+and the interior rings (holes) define areas that are excluded. To achive this, SqlServer is rigid about
+ring orientations for geographies.
+Kind | requested Orientation
+--- | ---
+outer rings | **counter clockwise**
+inner rings | **clockwise**
+
+**This is _currently_ not representable using NetTopologySuite geometries** and the `SqlServerBytesWriter`
+throws an `ArgumentException` if writing a geometry is requested that has an exterior ring oriented **clockwise**.
+
+#### Measures
+SqlServer geography types use the metric system for measures like length, distance and area.
+For NetTopologySuite geometries everything is planar and thus all return values are in the unit of the input 
+coordinates. In case the coordinates are geographic these values are mostly useless.    
+Furthermore you can easily create buffers of geometries that exceed the extent of a hemisphere. SqlServer rejects these.
+

src/Directory.Build.props

@@ -33,7 +33,7 @@
   <PropertyGroup Condition=" '$(GITHUB_ACTIONS)' == 'True' ">
     <Deterministic>true</Deterministic>
     <ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
-    <NtsBuildMetadata Condition=" '$(NtsBuildMetadata)' == '' ">ci.github.$(GITHUB_ACTION)</NtsBuildMetadata>
+    <NtsBuildMetadata Condition=" '$(NtsBuildMetadata)' == '' ">ci.github.$(GITHUB_RUN_ID)</NtsBuildMetadata>
 
     <NtsOfficialRelease Condition=" '$(GITHUB_REF)' == 'refs/heads/master' And '$(GITHUB_EVENT_NAME)' == 'push' ">true</NtsOfficialRelease>
   </PropertyGroup>