Data¶

Formats¶

Every format, with how to add it and its limits, is listed on Supported Data Formats.

Add data with Map › Add Data, by dropping files on the window, or by passing them on the command line (rustgis places.geojson). A CSV without coordinate columns, or a layer without geometry, opens as a standalone table, listed under the map in Contents. Map › Add Data › Graphics Layer adds a layer for drawn graphics, and Insert › Layer Templates adds empty layers with ready-made schemas to draw into.

Vector coordinates are WGS 84 longitude/latitude and are displayed in Web Mercator. GeoPackage, GeoParquet and FlatGeobuf files in another coordinate system (any EPSG code) are converted as they are read. Rasters keep their own coordinate system (any EPSG code, such as UTM zones or national grids) and are reprojected on the fly as they draw.

Formats through GDAL¶

When GDAL is installed (its ogr2ogr and ogrinfo programs on the PATH, or the folder holding them in RUSTGIS_GDAL_BIN; GDAL 3.7 or later), the desktop app also opens the vector formats GDAL reads: KML and KMZ, GPX, GML, DXF, File Geodatabases, MapInfo, OpenStreetMap and more. RustGIS doesn't link to GDAL: each layer is converted once, by ogr2ogr, into a FlatGeobuf with a spatial index in WGS 84 (GDAL reprojects it), kept in the cache folder (~/.cache/rustgis/gdal on Linux, ~/Library/Caches/RustGIS/gdal on macOS, %LOCALAPPDATA%\RustGIS\cache\gdal on Windows, or RUSTGIS_GDAL_CACHE). Adding the file again reuses the conversion until the file changes, and large layers stream like any large FlatGeobuf (below). Every layer of the file is added; a layer mixing geometry types, as KML often does, is added as one layer per type. Projects remember the original file and convert it again if the cached copy is gone.

Large files¶

GeoPackage, GeoParquet and FlatGeobuf files with more than 100,000 features are read in place rather than loaded whole, so files far larger than memory open in a moment. The layer reads the features in view, using the file's own spatial index (the GeoPackage R-tree, the FlatGeobuf packed R-tree, GeoParquet row-group bounding boxes), in the background as the map moves. When a view holds more than 250,000 features (100,000 in the web app), the layer draws an evenly spread sample of them and its tooltip in Contents says so: zoom in to see them all. Smaller files load whole; layer.addData with "stream": true or false overrides the choice.

A streamed layer works like any other for symbology, labels, pop-ups, selection and the attribute table (which lists the features read for the view). Geoprocessing tools read the whole file. Edits are refused, since the features are read again as the view moves: right-click the layer in Contents and choose Load All Features (layer.loadAll) to load it into memory and edit it. Projects save the layer's file path, not its features, and read the file again when they open; a browser upload is kept in the project.

Rasters¶

Add a GeoTIFF or an ASCII grid with Add Data, by dropping it on the window, or in the web app by picking it. An ASCII grid takes its coordinate system from a .prj file next to it that names an EPSG code; otherwise, and always in the web app, which only sees the one file, it must be in longitude/latitude degrees. Exporting a raster opened from an overview writes that overview. GeoTIFFs may be regular or cloud-optimised: grey, RGB(A), palette (coloured by the file's colour table, as land cover such as the NLCD is) or multiband, of any pixel type, tiled or striped, and compressed with Deflate, LZW, PackBits or JPEG. The coordinate system is an EPSG code, or the file's own projection described in its GeoKeys (Albers, Lambert conformal conic, transverse Mercator, Mercator, Lambert azimuthal, stereographic, equirectangular and others), which an exported GeoTIFF keeps. A raster too large to hold in memory (more than 120 million samples, 32 million in the web app) opens from its largest overview that fits; one without overviews opens as an overview made as it is read, a strip or tile at a time (every second, fourth… pixel each way), so reading it takes as long as decoding the whole file once.

Selecting a raster layer in Contents shows the Raster Layer tab group:

Clicking a raster with the Explore tool shows its pixel values. Projects remember a raster's file path and reopen it; rasters added in the browser are stored inside the project.

Project items¶

RustGIS saves pieces of a project as files you can share and reuse:

Packages are zip files. A mobile map package keeps only the visible layers and simplifies their geometry, for phones and tablets. Styles can also be imported from the layers of a layer file, map file or project. Insert › Layer Templates adds empty layers with ready-made schemas (places, routes, areas, observations…) to draw into. Add Folder connects a folder to the Catalog, which also lists the project's layouts, styles and tasks. A task's steps each run a command; New Task From History turns the geoprocessing history into a task you can replay.