Tiled Imagery

Uploading Tiled Imagery (Slippy Maps)

A Slippy Map is an architecture for building mapping applications on the web. It was popularized by the Open Street Map (OSM). While this technology was designed for geospatial industry, it works effectively for any use case involving large image such as whole slide scans in pathology.

A core component of Slippy Maps is that the images should be served as tiles on a grid. Tiling images is an efficient way to browse large amounts of raster and vector map data that would be much too large to render as a single map image. Tiles can be loaded on the fly as a user browses around a map to give the impression of a large seemless image.

To work with tiled imagery, you must have a tile URL like the one below:{z}/{x}/{y}.png

To import your tile URL data, you can generate a JSON file with the following structure.

tileLayerUrl (required)

Tile URL


Top left and bottom right coordinates (x,y) or (lat, lon). Use bounds to shard a large map into smaller sections to make labeling tasks smaller.

minZoom (optional)

Sets minimum zoom level

maxZoom (optional)

Sets maximum zoom level

epsg (optional)

EPSG code for specifying the geospatial coordinate system.

You can create a file with .json extension that has data as shown in the example below.

  "tileLayerUrl": "{z}/{x}/{y}.png?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cHM6Ly9wdWJsaWMtdGlsZXMuZHJvbmVkZXBsb3kuY29tLzE0OTk5OTQxNTVfREFOSUVMT1BFTlBJUEVMSU5FX29ydGhvX3Fmcy8qIiwiQ29uZGl0aW9uIjp7IkRhdGVMZXNzVGhhbiI6eyJBV1M6RXBvY2hUaW1lIjoyMTQ1OTE0MTE4fX19XX0_&Signature=O~50rrGXdEC6Hi8jPJ3dbT~UtBd7Cw6iQPTxdJ8LU2IaoxeP22R3JpKPkLN3T3~Lcw3CyX7uft2Baj0MH93qUoCYyN~~jNX3OMkYV2jbrHDezf6zQRHAabXX-L2bL-JEGfFL6z3DWccOFeCH56CuhgC29k5CJx7I34P-LQJdnAUsA-KaqKH1IyYsHStRIfmMzdXNAWU58FTfqVljq9SbKXxfgdr2SZ~7VgLaZ8IhA0WnlKUo-JgqTd~jYa5mGCpR8351IMK0aMuY4Mld4SOXssQ-rOtlZtypvo8FDp474TlGIEGz5PHxGOPsqLPF19hEYTgoPqsUj8QEuiTfg-cmsg__&Key-Pair-Id=APKAJXGC45PGQXCMCXSA",
  "bounds": [
  "minZoom": 10,
  "maxZoom": 23,
  "epsg": "EPSG4326"

Download this example JSON file here.

Upload the JSON file by clicking Add Data in Labelbox.

Attach the uploaded dataset to the project. Make sure to select the Image Labeling interface.

Tiled maps in action!

Tiled maps in action!

Maximum number of annotations per tile map

It is highly recommended to limit the extent of the map by specifying bounds such that each task has no more than 100 bounding boxes or 50 polygon annotations. Labeler will be alerted with a message that they have exceeded the maximum limit of annotation in that map.

Tiled Imagery

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