Appearance
Add Layer Tool
Overview
Horizon provides two tools for bringing spatial data into the map:
| Tool | Icon | Purpose |
|---|---|---|
| Layer Catalog | Browse Catalog icon | Browse and add layers from Horizon's built-in data catalog, or connect to external ArcGIS REST, WMS, and WMTS services, or a GeoParquet file |
| Upload File to Map | Upload icon | Load local spatial files (KML, GPX, GeoJSON, Shapefile, ZIP, CSV, GeoPackage) directly from your computer |
Both tools are available as action buttons in the left toolbar.
Layer Catalog
Opening the Layer Catalog
- Click the Browse Catalog icon (tooltip Browse Layer Catalog) in the left toolbar
- The Layer Catalog dialog opens — a resizable, draggable 3-panel interface:
- Left — Filter Sidebar (categories and layer type filters)
- Centre — Layer List with search and toolbar
- Right — Preview Panel (opens when you preview a layer)
- Click the icon again, or click Close, to dismiss the dialog — opening other panels leaves it on screen (opening the catalog itself closes the Upload dialog and any open left-side panel)
INFO
The dialog title shows the count of matching layers, e.g. Layer Catalog (42 of 180 layers).
Searching Layers
- The Search box at the top of the layer list filters layers in real time (300 ms debounce) as you type
- Search matches layer name, category, or description
- Click the × inside the search box to clear the search term
Filtering Layers
Two types of filters work together to narrow down the list:
Geometry Type Quick Filters
Chips in the toolbar (Polygon, Point, Line, Raster) toggle geometry type filters on and off. Only the geometry types actually present in the catalog are shown, each with a count:
- Click a chip to activate it (highlighted in blue) — only layers with that geometry type are shown
- Click again to remove the filter
- Multiple geometry types can be active at the same time
Filter Sidebar
Click Show Filters / Hide Filters in the dialog footer to expand or collapse the sidebar.
The sidebar contains two filter sections:
Categories
- Each data category is listed with a checkbox and its layer count
- Tick a category to filter by it; untick it to remove the filter
- The sidebar has its own search box (Filter options...) to find categories by name or by layer name within a category
- Active categories appear as closable chips in the Active Filters Bar
Layer Type
Filter by the technical type of the layer. Only the types present in the catalog are listed, each with a count:
| Layer Type | Description |
|---|---|
| Feature Layer | Vector features (point, line, or polygon) with attribute data |
| Map Image | ArcGIS MapServer layers rendered as images |
| WMS | OGC Web Map Service (raster tiles) |
| WMTS | OGC Web Map Tile Service (cached tiles) |
| WFS | OGC Web Feature Service |
| Tile Layer | Cached tile layers |
| Imagery / Raster Layer | Image services and raster layers |
| Group Layer | Grouped sets of related layers |
| GeoParquet | GeoParquet files (see GeoParquet Files) |
Active Filters Bar
When one or more category or layer type filters are active, the Active Filters Bar appears below the toolbar:
- Collapsed view: Shows a summary chip count and filter preview; click the expand chevron to see all chips
- Expanded view: Shows each active filter as a closable chip — click the × on any chip to remove it
- Clear All: Removes all active category and layer type filters in one click
Layer List
Each item in the layer list shows:
- Checkbox — selects the layer for batch addition via the Selection Cart
- Geometry icon, layer name and category
- Visibility toggle (Show layer / Hide layer) and opacity button (Adjust opacity), which set how the layer arrives on the map
- Type badge
- View layer details (info) button — opens the Preview Panel on the right
- Add to map (+) button — adds the layer immediately to the map
While the preview panel is open, the visibility, opacity and badge columns are hidden. Click a layer's info button to inspect it before adding. The Refresh button in the toolbar reloads the catalog from the server.
INFO
For large catalogs (more than 50 layers), the list uses virtual scrolling for performance.
Layer Preview Panel
Clicking the info button (View layer details) on any layer opens the Layer Details panel on the right side of the dialog showing:
- Layer title and category
- Display Settings — a Visibility toggle and Opacity slider to pre-set the layer before adding
- Description (Show more / Show less for long text)
- Search keywords (if any)
- View Metadata button (if available)
- Add to Selection — adds the layer to the Selection Cart for batch addition (Remove from Selection once added)
- Add & Close — adds the layer and closes the dialog
- Add to Map — adds the layer with the current visibility/opacity settings
Close the preview panel with the × button to return to a two-column layout.
Selection Cart
The Selection Cart at the bottom of the layer list lets you batch-select layers and add them all at once:
- Check the checkbox on one or more layer items to select them
- The cart expands to show the selected layers with their names
- Click Add X Layers to Map to add all selected layers simultaneously
- Remove (×) individual layers from the cart before adding
- Clear All clears all selections (with a confirmation prompt for more than 3 layers)
- Undo restores a recently removed selection for a short window
INFO
Up to 30 layers can be queued at one time. Exceeding this limit shows a warning and disables the batch add button.
Adding External Services
Click the Add External Service button in the Layer Catalog toolbar to connect to an external map service.
Supported Service Types
| Service Type | Description |
|---|---|
| ArcGIS MapServer | Standard ArcGIS map service with one or more layers |
| ArcGIS FeatureServer | Editable feature layers with query capabilities |
| ArcGIS ImageServer | Satellite imagery, aerial photos, or raster datasets |
| ArcGIS VectorTileServer | High-performance vector tile basemaps |
| WMS | OGC Web Map Service (cross-platform raster layers) |
| WMTS | OGC Web Map Tile Service (cached tile layers) |
| GeoParquet (file URL) | One .parquet file in WGS84: points, lines or polygons. For a private file, use its SAS URL. See GeoParquet Files |
Steps
Click Add External Service in the Layer Catalog toolbar
Select the Service Type from the dropdown, or leave it on its default, ArcGIS MapServer — the type is switched to match the URL when you validate it
Paste or type the Service URL into the URL field
Example URLs:
- MapServer:
https://example.com/arcgis/rest/services/MyService/MapServer - FeatureServer:
https://example.com/arcgis/rest/services/MyService/FeatureServer/0 - WMS:
https://example.com/wms?service=WMS - WMTS:
https://example.com/wmts?service=WMTS - GeoParquet:
https://example.com/data/file.parquet
- MapServer:
Click Validate & Load Layers (or press Enter)
The service is contacted and available layers are listed
Check the layers you want to add (use Select All / Deselect All as needed)
Use the search box to filter by layer name if the list is long
Click Add X Layer(s) to Map
For an ArcGIS MapServer entered by its base URL (ending in /MapServer):
- One layer ticked — it is added on its own and takes the service's default visibility for that layer, so it can arrive switched off; turn it on in the Layer Panel
- Two or more layers ticked — they are added as one visible group named after the service, and each layer can be switched on or off individually in the Layer Panel
A URL that names one layer (for example .../MapServer/1) lists just that layer, and it is added switched on. A cached (tiled) MapServer whose tiles match the map is added as a single tile layer instead.
Auto-Detection
The service type is automatically detected from the URL when you click Validate & Load Layers — for example, a URL containing /MapServer switches the type to ArcGIS MapServer, and a URL whose path ends in .parquet (or .geoparquet) switches it to GeoParquet. You do not need to set the service type manually.
GeoParquet Files
A GeoParquet file is a whole data file, not a service: Horizon downloads it and draws it from your browser.
Downloaded on Validate & Load Layers. The whole file is downloaded then, up to 100 MB, and listed as one layer. Its description reads, for example, GeoParquet: 51,496 point features, 1.2 MB.
WGS84 or Web Mercator only. The file must be in WGS84 (EPSG:4326) or Web Mercator. A file in a projected system (such as MGA zone 55), or in another datum (such as GDA94 longitude/latitude), is refused with the reason, so that nothing is drawn in the wrong place: re-export it in EPSG:4326.
A private file needs its SAS URL, for example one on Azure Blob storage: the file's address with its access token added.
A treetop file is drawn by height. A point file with a
height_mfield is a treetop file:- its treetops are coloured by height in the canopy height model's classes, and gathered into bins further out than 1:4,000;
- its layer panel has a Tree Height Filter and Tree Style: see Layer Panel: Treetop Layers.
To count and measure treetops inside an area, use the Treetops tool.
Bookmarks keep it, with its filter and style. Opening the bookmark downloads the file again, so a SAS that has expired since must be renewed.
It prints the part inside the print area, at the print's scale.
In the Layer Catalog, entries that are GeoParquet files show a Parquet badge, and are listed under the GeoParquet type filter.
| Message | What to do |
|---|---|
| File not found. Check the URL: a private Azure container also answers this way when the URL has no valid SAS token. | Check the address, and add a valid SAS token for a private file |
| Access denied. The SAS token may have expired, or it may not allow reading this file. | Get a new SAS URL |
| This file is … MB, over the 100 MB limit for GeoParquet layers. | Use a smaller file, or split the data into several files |
| This file is in a projected coordinate system… re-export it in EPSG:4326. | Re-export the file in WGS84 (EPSG:4326) |
| This file's longitude/latitude are in another datum… re-export it in EPSG:4326. | Re-export the file in WGS84 (EPSG:4326); a GDA94 file would be drawn about 1.5 m off |
| The download stopped: the file server sent nothing for 60 seconds. Try again later. | The connection stalled; try again |
Error Messages
| Error | Cause |
|---|---|
| Network error: Unable to reach the service | The server is down or the URL is unreachable |
| Access blocked (CORS restriction) | The service does not allow browser-based access |
| Authentication required | The service requires login credentials |
| Access denied | You do not have permission to access this service |
| Service not found | The URL does not point to a valid service endpoint |
Upload File to Map
This section covers the essentials. For the full reference — including GeoJSON handling, coordinate-system detection and the messages shown when features are skipped — see the Upload Tool guide.
Opening the Upload Dialog
- Click the Upload icon in the left toolbar
- The Upload File to Map dialog opens as a standalone draggable dialog
INFO
The Layer Catalog floats independently — it stays open while you open and close the Upload dialog, other tool panels, or the System settings dialog. Dismiss it with its own toolbar icon or its Close button.
Supported File Types
| Format | Extension | Notes |
|---|---|---|
| Shapefile | .shp | Single shapefile component; coordinate system must be selected manually |
| Shapefile ZIP | .zip | Recommended — includes .prj file for automatic coordinate detection |
| GeoJSON | .geojson, .json | Coordinate system worked out automatically — no dropdown appears |
| KML | .kml | Keyhole Markup Language (Google Earth format) |
| GPX | .gpx | GPS Exchange Format for tracks, routes, and waypoints |
| CSV | .csv | Comma-separated values with coordinates; displayed with clustering |
| GeoPackage | .gpkg | Each feature table becomes its own layer; read on the server |
File size limit: 100 MB maximum per upload (55 MB for a GeoPackage).
TIP
Use a ZIP bundle for shapefiles whenever possible. The .prj file inside the ZIP is automatically read to determine the correct coordinate system — no manual selection required.
Uploading a File
- Select a file — drag and drop a file onto the drop zone, or click the drop zone to browse for a file
- The file name, type, and size are displayed in the drop zone once selected
- For SHP or ZIP files: set the coordinate system if not auto-detected (see below)
- Click Upload to Map in the dialog footer
- A progress indicator shows the processing stage: Reading → Parsing → Creating → Complete
- On success:
- The layer is added to the map automatically
- The map zooms to fit the uploaded features
- If the file contains polygons, the total area is displayed in hectares
- Click × next to the file name to clear the selection and start again
Coordinate System Selection
For .shp files and ZIP bundles without a .prj file, a coordinate system dropdown is shown:
- Default: GDA94 / MGA Zone 55 (EPSG:28355) — suitable for most Tasmanian data
- Select the appropriate projection to ensure the data is placed correctly on the map
When a ZIP is uploaded that contains a .prj file, the coordinate system is detected automatically: the dropdown is hidden and a Coordinate system detected from ZIP notice names the system — no selection is needed.
Projection notice for .shp-only uploads
A standalone .shp file contains no coordinate-system information — that data lives in the .prj file, which is only present in a ZIP bundle. Because of this, Horizon cannot read the exact coordinate system, but it tries to auto-detect it: it reinterprets the file's raw coordinates under each candidate system and picks the one that places your data inside Tasmania. After a .shp-only upload you'll see one of these notices:
- Coordinate system auto-corrected (success) — the system you selected didn't fit, so Horizon detected a better one and used it instead (your data now falls within Tasmania). The dropdown updates to show the corrected system. If it still looks wrong, pick another and upload again.
- Selected coordinate system looks wrong (warning) — the coordinate values in the file don't match the kind of system you selected (degrees vs metres) and no better one could be auto-detected. For example the file holds latitude/longitude degrees but you chose a projected MGA zone, or vice versa. Pick the matching system, or re-upload as a ZIP.
- Shapes appear outside Tasmania (warning) — the shapes fell outside the expected Tasmania area and no fitting system was found. Try a different coordinate system, or re-upload as a ZIP.
- Coordinate system taken from your selection (info) — your selection fit, but this is a reminder that the shapes were placed using the projection you chose. Check they landed in the right spot.
Limitation
These checks catch a system of the wrong kind (degrees vs metres) or the wrong MGA zone. They cannot tell apart two systems of the same zone that differ only by datum — for example GDA94 / MGA Zone 55 vs GDA2020 / MGA Zone 55 (only ~1.8 m apart). The only reliable way to get the exact coordinate system is to upload a ZIP that includes the .prj file.
TIP
These checks only apply to .shp-only uploads. A ZIP with a .prj file is detected automatically and needs none of them.
GeoJSON Uploads
GeoJSON files are accepted as either .geojson or .json, and may be a FeatureCollection, a single Feature, or a bare geometry object. No coordinate system dropdown appears — Horizon reads the system the file declares, or works it out from the coordinates themselves, and shows a notice only when the result was ambiguous.
If some records in the file have no geometry, they are skipped rather than failing the upload:
- Some features were skipped — the upload succeeded, but the new layer holds fewer features than the file does.
- Nothing to add to the map — no feature could be drawn, so nothing was added and the map was left where it was.
In both cases, re-export the file from the source system and check for records with empty geometry.
See GeoJSON Files and When Features Are Skipped for the full detail.
Managing Added Layers
After adding layers using either tool, manage them through the Layer Panel:
- Visibility — toggle layers on or off
- Transparency — adjust layer opacity
- Ordering — drag layers to reorder them
- Properties — access layer-specific actions via the three-dots menu
See the Layer Panel documentation for full details.
Troubleshooting
| Issue | Solution |
|---|---|
| Layer not appearing after addition | Check layer visibility in the Layer Panel; the layer may be hidden |
| Search returns no results | Try shorter or different keywords; check if category/type filters are active |
| Filter sidebar not visible | Click Show Filters in the dialog footer |
| External service fails to load | Verify the URL is correct and the service is publicly accessible |
| CORS error on external service | The service does not permit browser access; use a different service or proxy |
| Upload fails with "Invalid File Type" | Only .shp, .csv, .kml, .gpx, .zip, .geojson, .json, .gpkg are supported |
| Upload fails with "File Too Large" | File must be under 100 MB (55 MB for a GeoPackage) |
| External MapServer layer added but not showing | A single layer from a base MapServer URL keeps the service's default visibility; switch it on in the Layer Panel |
| Shapefile appears in wrong location | Select the correct coordinate system before uploading, or use a ZIP with a .prj file |
| "Shapes appear outside Tasmania" warning | The .shp's coordinate system likely differs from your dropdown choice; pick another system or re-upload as a ZIP |
| "Selected coordinate system looks wrong" warning | The file's coordinates are degrees but you picked a projected system (or vice versa); choose the matching system or re-upload as a ZIP |
| ZIP upload has no auto-detected projection | The ZIP does not contain a .prj file; select the coordinate system manually |
| "Some features were skipped" after upload | Records with no geometry were left out; the rest were added. Re-export and check for empty geometry |
| "Nothing to add to the map" | No feature in the file could be drawn; re-export and confirm the records carry geometry |
| GeoJSON upload rejected as not GeoJSON | The file is valid JSON but not GeoJSON; re-export it as a FeatureCollection |
| CSV layer not displaying points | Ensure the CSV file has valid coordinate columns |
| Performance issues with many layers | Remove unused layers via the Layer Panel; avoid adding very large datasets simultaneously |
Video Tutorial
Watch this guide on using the Add Layer Tool: