LTRData Library

A collection of reusable .NET libraries used by tools and applications by Olof Lagerkvist, LTR Data. The repository contains independently versioned library projects covering general utilities, data and networking, geographical calculations, mathematical expressions, plotting, and platform integration.

Packages and components

Each library project below uses its project name as its NuGet package ID. Choose the packages needed by your application; dependencies between them are declared in the project files. Namespaces can differ from package names.

Package / source	Purpose
LTRData.Extensions	General-purpose extensions for buffers and spans, streams, collections, formatting, reflection, numeric operations, and command-line parsing.
LTRData.Extensions.Native	Native memory helpers, memory comparison, and native library/symbol access; individual APIs have OS and runtime dependencies.
LTRData.Data	Collection and query helpers, caching, CSV reading/writing, reflection-based data mapping, and Entity Framework integration.
LTRData.Xml	XML serialization and extensions, configuration, and time-zone-aware date/time helpers.
LTRData.Net	HTTP and download helpers, IP address ranges, network extensions, and pipeline helpers.
LTRData.Web	RSS models/downloads and linked XML resources. Server-specific helpers live in WebServerUtils.
LTRData.WebServerUtils	HTTP server utilities for classic ASP.NET and ASP.NET Core, including response/file handling and HTTPS-related helpers.
LTRData.Geodesy	WGS84, RT90 and SWEREF99 coordinates and conversions, grid squares, solar events, and moon-phase calculations.
LTRData.PolyGeometry	Point, line, path, polygon and bounding-rectangle types, with WKT parsing.
LTRData.Placemarks	Simplified KML models, region lookup and geographical geometry helpers; modern targets use NetTopologySuite.
LTRData.Graphics	Color conversion/matching and 3D vector extensions.
LTRData.MathExpression	Math parsing, diagnostics, binding and interpreted evaluation, plus portable expression-tree diagram content/layout. Legacy parser APIs remain available.
LTRData.FunctionPlotting	Parser-independent function sampling, clipped plot geometry, and numerical differentiation/integration of samples.
LTRData.Graphics.SkiaSharp	SkiaSharp renderers for function plots and expression diagrams, plus PNG encoding.
LTRData.Compat.System.Management	A System.Management-style API over Microsoft.Management.Infrastructure (CIM), including asynchronous operations; not a complete System.Management replacement.
LTRData.PerformanceCounters	Thermal-zone temperature enumeration through Windows performance counters and, on applicable targets, Linux sysfs.

For example, add the general extensions package to an application:

dotnet add package LTRData.Extensions

See LTRData packages on NuGet for published versions and their framework assets. Source on the default branch may be newer than a published package.

Target frameworks and platform dependencies

Most library projects inherit these build targets from Directory.Build.props:

• .NET Framework 3.5, 4.0, 4.6 and 4.8.
• .NET Standard 2.0 and 2.1.
• .NET 8, 9, 10 and 11.

The exceptions are:

Package	Targets
LTRData.Compat.System.Management	.NET Framework 4.6/4.8, .NET Standard 2.0/2.1, .NET 8/9/10/11
LTRData.WebServerUtils	.NET Framework 4.0/4.6/4.8, .NET Standard 2.0/2.1, .NET 8/9/10/11
LTRData.Graphics.SkiaSharp	.NET 8/9/10/11

These are compilation targets, not a guarantee that every API is available on every framework or operating system. Conditional compilation and dependencies vary by target; consult the linked project files and the API you intend to use.

• The modern expression and plotting code is independent of a graphics backend. Rendering through SkiaSharp requires compatible native assets and fonts. Linux applications need the matching Linux native package; FreeBSD native deployment remains deferred. See the rendering and deployment notes.
• WebServerUtils uses System.Web on .NET Framework and ASP.NET Core dependencies on modern targets, including the Microsoft.AspNetCore.App shared framework for .NET 8/9/10/11. LTRData.Web is kept separate from these server runtime references.
• Native helpers, CIM operations and temperature readings depend on the relevant operating-system libraries, services or hardware interfaces. A .NET Standard target alone does not establish platform availability.

Mathematical expressions and plotting

The modern API separates parsing and binding in LTRData.MathExpression, numerical sampling and geometry in LTRData.FunctionPlotting, and native rendering in LTRData.Graphics.SkiaSharp. FunctionPlotting also accepts ordinary numerical delegates without requiring an expression parser.

Start with the expression language specification, rendering examples, and consumer migration and sample calculus notes. Fixed-count sampling does not guarantee detection of every discontinuity or finite asymptote; adaptive sampling and previous-value recurrence remain deferred.

The design documentation preserves the investigation and implementation history. Some sections describe earlier experimental checkpoints; the modern APIs are now part of this repository.

Building and testing

Use the .NET 11 SDK, as in the CI workflow. Building all targets also requires the corresponding reference assemblies; running tests requires the runtime for the selected target.

From the repository root:

dotnet restore Library.slnx
dotnet build Library.slnx -c Release --no-restore
dotnet test Library.slnx -c Release --no-build --no-restore -f net10.0
dotnet test Library.slnx -c Release --no-build --no-restore -f net11.0

CI is configured to build on Windows, Ubuntu and macOS. It runs the configured test targets on Windows and .NET 10 and 11 tests on Ubuntu/macOS. The main test project targets .NET Framework 4.8 and .NET 8/9/10/11; Rendering.Tests targets .NET 8/9/10/11 and exercises native SkiaSharp rendering.

Release builds generate NuGet packages. Set LocalNuGetPath to a local feed directory when building packages for other repositories, and build the required dependency packages as well. The local package workflow explains output configuration, consumer restore, and package-origin verification.

Publishing packages to NuGet.org

Publishing is an explicit, tag-triggered operation, separate from regular CI. On the master branch, create and push an annotated publication tag:

git checkout master
git pull --ff-only
git tag -a publish/2026.11.12.1 -m "NuGet publication 2026.11.12.1"
git push origin publish/2026.11.12.1

The publishing workflow accepts publish/* tags pointing to a commit reachable from master. It restores, builds, runs Windows tests, collects both .nupkg and .snupkg files, and only then publishes using NuGet.org Trusted Publishing. The nuget-publish GitHub environment may require approval before the publishing job starts. Ordinary pushes and pull requests never publish packages.

Publication tags identify batches, not package versions. Each project keeps its own Version/FileVersion/PackageVersion from MSBuild; the workflow never overrides those values. Existing package versions are skipped by dotnet nuget push --skip-duplicate. Bump the individual project versions when their contents need to change, since published NuGet package versions cannot be replaced.

Required one-time setup:

• A NuGet.org Trusted Publishing policy for LTRData/Library and workflow filename publish-nuget.yml, with GitHub environment nuget-publish if the policy is environment-restricted.
• A GitHub Actions repository variable NUGET_USER containing the NuGet.org account username that owns the trusted publishing policy (not an email, API key, or GitHub username).
• A GitHub Actions nuget-publish environment; restrict allowed deployments to the intended publish/* tags and optionally require approval.

The workflow requests a short-lived NuGet credential only after build and test completion, and publishes the exact generated packages rather than rebuilding with a different version or SDK.

Related code and provenance

Consumers include the netexpr command-line tool and Windows GraphViewer. The separate LTRLib repository retains legacy libraries, including Windows drawing compatibility used by older consumers. The migration notes explain how netexpr and GraphViewer use the newer APIs here.

Geodesy includes work derived from Björn Sållarp's MightyLittleGeodesy, extended by Olof Lagerkvist. Existing source headers retain authorship and license notices.

License and third-party notices

LTRData Library is distributed under the MIT License. See THIRD-PARTY-NOTICES.md for embedded third-party source, attribution requirements, and additional context for dependency-license findings reported by automated scanners such as FOSSA.