Tile Map Service for .NET 5 / .NET 8

Simple and lightweight implementation of tile server basic features for .NET 5 / .NET 8 platforms. Provides access to tiles stored in several source types and serving them using various protocols.

Demo page

Features

• Supported tile sources:

Source type	EPSG:3857	EPSG:4326	Notes
Local file system	✓	✓	Each tile in separate file in Z/X/Y.ext folder structure
MBTiles (SQLite)	✓	—	MBTiles 1.3 Specification
GeoTIFF local file	✓	✓	GeoTIFF basic support with EPSG:3857 or EPSG:4326 source image SRS only
XYZ tile service	✓	✓	XYZ with local cache for EPSG:3857 SRS
TMS tile service	✓	✓	TMS with local cache for EPSG:3857 SRS
WMTS tile service	✓	✓	WMTS with local cache for EPSG:3857 SRS
WMS service	✓	—	WMS, versions 1.1.1 and 1.3.0, cache for EPSG:3857 SRS
PostGIS database	✓	—	Mapbox Vector Tiles from geometry column with EPSG:3857 SRS only

• Supported protocols (service endpoints) for serving tiles:

Endpoint	EPSG:3857	EPSG:4326	Endpoint Url	Formats	Notes
XYZ (Tiled web map)	✓	✓	/xyz	png, jpeg, webp, mvt	Can be REST style url (/{z}/{x}/{y}.ext) or url with parameters (&x={x}&y={y}&z={z})
TMS (Tile Map Service)	✓	✓	/tms	png, jpeg, webp, mvt
WMTS (Web Map Tile Service)	✓	—	/wmts	png, jpeg, webp, mvt	Support both RESTful and KVP GetTile url syntax
WMS (Web Map Service)	✓	—	/wms	png, jpeg, tiff (geotiff)	WMS versions 1.1.1 and 1.3.0

• Coordinate system / tile grid support: Web Mercator / Spherical Mercator / EPSG:3857, basic support for geodetic EPSG:4326.
• Tile image formats: raster (PNG, JPEG, WEBP) 256×256 pixels tiles, basic support of TIFF output and PBF / MVT (vector tiles).
• Local cache for tiles from external tile services sources (modified mbtiles format database file, EPSG:3857 only), with blank tiles detection support.
• Configuration in JSON file.
• Reading sources configuration using /api endpoint (local requests only).

Technologies

There are two separate solutions and corresponding projects, sharing the same source code files:

Property	.NET 5	.NET 8
SDK	.NET 5.0	.NET 8.0
MS Visual Studio	2019	2022
Status	Legacy	Active

Using

• Microsoft.Data.Sqlite for working with SQLite database.
• SkiaSharp for raster images processing.
• BitMiracle.LibTiff.NET for reading source GeoTIFF files and creating output TIFF images.
• Npgsql .NET data provider for PostgreSQL.
• OpenLayers with OpenLayers LayerSwitcher for displaying layers.
• NUnit for tests.

Configuration file

Tile sources are defined in appsettings.json configuration file.

Running framework-dependent deployment

Check if .NET 5 or .NET 8 runtime is installed on target system:

dotnet --info

The Microsoft.AspNetCore.App 5.0.3 / 8.0.0 (or later versions) should present in list.

There is known issue for .NET 5 and libssl 3.x compatibility on Linux systems, use .NET 8 in this case.

Run the application using command:

dotnet tms.dll

After start, it will listen on default TCP port 5000 (using in-process Kestrel web server) and tile service with demo page will be available on http://localhost:5000/ address; to enable remote calls allow connections to this port in firewall settings.

Further improvements on Linux

Some improvements can be made for better using this application in real environment:

• Install nginx and configure it as reverse proxy server for Kestrel server.
• Configure application to run as a service, using systemd service manager.

TODOs

• Support for more formats (image formats, vector tiles) and coordinate systems (tile grids).
• Flexible settings of tile sources.
• Configuration Web API / Web UI with authentication.
• WMS client in Web UI.
• Compare with reference implementations (servers and clients).
• Using metatiles for better tiles quality.
• Include test dataset(s) created from free data.
• Extended diagnostics, error handling and logging.
• Performance tests.
• Live demo.

Some MBTiles sample datasets

• World Countries MBTiles by ArcGIS / EsriAndroidTeam
• Satellite Lowres raster tiles Planet by MapTiler
• Custom vector tiles from Georaphy Class example MVT

All external tile sources (services) in the provided appsettings.json file are only for development / testing, not for production use.

References

• MBTiles Specification
• Tile Map Service Specification
• OpenGIS Web Map Tile Service Implementation Standard
• Serving Dynamic Vector Tiles from PostGIS
• GeoTIFF Format Specification
• Using WMS and TMS in Leaflet
• QGIS User Guide: Working with OGC / ISO protocols
• Deploy ASP.NET Core on Linux with Nginx