Consider taking individual layers offline as offline data if you want to construct the map or scene yourself and provide users with up-to-date information from ArcGIS Online or ArcGIS Enterprise. This topic describes how to generate and download offline data to use the following layers offline:
- Feature and annotation layers — Download a specific geographical area from a sync-enabled feature service into a mobile geodatabase. Edits can be synchronized with other users when connectivity is restored. This synchronization process allows the app to maintain an up-to-date view of the feature data.
- Tiled layers
- Vector tiled data — ArcGIS vector tile services or vector basemaps in ArcGIS Online
- Image tiled data — Tiled ArcGIS map services, tiled ArcGIS image services, tiled basemaps or elevation sources in ArcGIS Online
You can export and download tiled layer caches locally and access them while your device is offline. It is important to note that you cannot edit tiled layer data (vector tiled data and image tiled data). If you require updates to the tiled layer data, you must export and download them again.
Feature and annotation layers
You can take features (including annotation, related records, and attachments) offline, from a feature service, by downloading them to geodatabase feature tables within a mobile geodatabase. To do this, the feature service must be hosted on ArcGIS Enterprise 10.2.2 or later for features or from a service hosted in ArcGIS Online, provided that the feature service has been sync enabled (allow disconnected editing with synchronization).
You can use an existing feature service or create feature services for your own data. To enable synchronization for a feature service, do the following:
- ArcGIS Online — Edit the feature service item and check the Sync check box.
- ArcGIS Enterprise — See Prepare data for offline use in the ArcGIS Server documentation.
To create the mobile geodatabase, you must do the following:
- Generate geodatabase parameters and define the area of interest, the layers, any expression filters, and so on, if required.
- Create the geodatabase, populate it with all the relevant features, and download it to the user's device.
Generate geodatabase parameters
When you create a mobile geodatabase, you must provide a set of parameters, described below, to define exactly which data is downloaded.
- The geographical area of interest. You typically supply the area of interest as an extent (in other words, an envelope) but point, line, and polygon (including multipart) geometries are also supported. This allows you to create more detailed areas of interest. Regardless of the geometry, any features that intersect with the supplied area of interest are extracted.
- The spatial reference of the mobile geodatabase.
- Individual layers can be managed using the
GenerateGeodatabaseParameters.layerOptionsproperty:- Determine which layers are included in the mobile geodatabase.
- Subset the features by providing an expression that filters features by attribute values, such as
ZONE = 'COM'. - The synchronization model controls how edits made to the mobile geodatabase are applied back to the feature service during synchronization. The model supported is defined by the data that was used to create the sync-enabled feature service. If the data is nonversioned, the synchronization model is per layer. This is the most flexible model, allowing you to synchronize on a layer-by-layer basis, based on the layers you specify. If the data is versioned, the synchronization model is per geodatabase. This synchronizes the entire geodatabase, including all layers and tables, at once.
- Specify whether to include feature attachments in the mobile geodatabase and whether they can be uploaded during synchronization.
- Identify whether tables related to the layer are also included in the geodatabase.
You can obtain a default set of parameters (GenerateGeodatabaseParameters) using the createDefaultGenerateGeodatabaseParameters() method on the GeodatabaseSyncTask. If you provide the area of interest, the default parameters will be generated taking into account the capabilities supported by the ArcGIS feature service. You can update these default parameter values before creating the geodatabase.
// Instantiate the geodatabase sync task.
val featureServiceUrl =
"https://sampleserver6.arcgisonline.com/arcgis/rest/services/Sync/SaveTheBaySync/FeatureServer"
val geodatabaseSyncTask = GeodatabaseSyncTask(featureServiceUrl)
coroutineScope.launch {
// Create generate geodatabase parameters for the selected extent.
val generateGeodatabaseParameters =
geodatabaseSyncTask.createDefaultGenerateGeodatabaseParameters(extent)
.getOrElse { error ->
return@launch logErr("Error creating geodatabase parameters: ${error.message}")
}
// Set the synchronization model per layer.
generateGeodatabaseParameters.syncModel = SyncModel.Layer
// Define the layers and features to use.
val marineLayerId = 0
val birdsLayerId = 1
val dolphinsOnlyWhereClause = "type = 11"
// Clear any existing layer options, and then populate the marine layer options.
generateGeodatabaseParameters.layerOptions.clear()
generateGeodatabaseParameters.layerOptions.add(
GenerateLayerOption(
layerId = marineLayerId.toLong(),
whereClause = dolphinsOnlyWhereClause
)
)
// Populate the bird layer options.
generateGeodatabaseParameters.layerOptions.add(
GenerateLayerOption(
layerId = birdsLayerId.toLong()
)
)
// Do not return attachments.
generateGeodatabaseParameters.returnAttachments = false
// Continues in next example...
Create the geodatabase
Obtain a job to generate and download the geodatabase by passing the GenerateGeodatabaseParameters to the GeodatabaseSyncTask.createGenerateGeodatabaseJob() method on the GeodatabaseSyncTask class. Run the job to generate and download the geodatabase to the device.
// ... continues from previous example.
// Create the generate geodatabase job, pass in the parameters and an output path for the local geodatabase.
val generateGeodatabaseJob = geodatabaseSyncTask.createGenerateGeodatabaseJob(
parameters = generateGeodatabaseParameters,
pathToGeodatabaseFile = destinationPath + File.separator + "localGeodatabase.geodatabase"
)
// Collect the job status when it changes: NotStarted, Started, Succeeded, Failed, etc.
coroutineScope.launch {
generateGeodatabaseJob.status.collect { jobStatus ->
when (jobStatus) {
JobStatus.Succeeded -> {
// If job succeeded, call a function to add local data to the map.
}
JobStatus.Failed -> {
// If job failed, report failure.
logErr("Failed to create local geodatabase.")
}
else -> {
// Other JobStatus cases include: Canceling, NotStarted, Paused, Started.
}
}
}
}
val jobStarted = generateGeodatabaseJob.start()
// Continues in the next example...
If you generate the geodatabase using these methods, it will automatically register the geodatabase with its original service. This allows the data in the geodatabase to be synchronized with the original service. If you want to load this geodatabase onto a number of devices and allow those users to synchronize changes with the original service, you must register these individual geodatabases with the original service.
Create layers from geodatabase feature tables
// ... continues from the previous example.
// Get the geodatabase from the generate geodatabase job.
val geodatabase = generateGeodatabaseJob.result().getOrElse { error ->
return@launch logErr("Error fetching the geodatabase: ${error.message}, ${error.cause}")
}
// Load the geodatabase.
geodatabase.load().onFailure { error ->
return@launch logErr("Error loading geodatabase: ${error.message}")
}
// Create a new feature layer for each feature table in the local geodatabase.
geodatabase.featureTables.forEach { geodatabaseFeatureTable ->
val featureLayer = FeatureLayer.createWithFeatureTable(geodatabaseFeatureTable)
map.operationalLayers.add(featureLayer)
}
// Make an annotation layer from each feature table that contains annotation data.
// Note: Annotation data is stored in an ArcGISFeatureTable, rather than the more generic FeatureTable.
geodatabase.annotationTables.forEach { annotationFeatureTable ->
val annotationLayer = AnnotationLayer(annotationFeatureTable)
map.operationalLayers.add(annotationLayer)
}
Now that you have a geodatabase on your local machine or device, you'll create the relevant layer from the geodatabase feature tables.
- Get the geodatabase from the generate geodatabase job.
- Load the geodatabase.
- Create feature layers from the geodatabase feature tables.
- Create annotation layers from the geodatabase annotation tables.
Tiled layers
Tiled layers typically provide geographical context to your map or scene as basemaps that display beneath your data layers. Tiled layers may also provide offline elevation data for visualizing 3D terrain in a scene. You can export and download tile caches directly to your device from any tiled data source that is export enabled. Esri provides a number of vector and raster basemaps for you to export and download:
- Download vector tiled data — ArcGIS vector tile services or vector basemaps in ArcGIS Online
- Download image tiled data — Tiled ArcGIS map services, tiled ArcGIS image services, or tiled basemaps and elevation sources in ArcGIS Online
Download vector tiled data
You can take vector tiled data offline by exporting it from an ArcGIS vector tile service and downloading it as a vector tile package (.vtpk) using the ExportVectorTilesTask class. The vector tile service used for this operation must support the creation of an offline vector tile cache; specifically, it must enable the export operation. Vector tiles contain vector representations of data that can be restyled for different purposes, such as day and night viewing. You can download default styling resources along with the vector tiles and custom style resources from ArcGIS Portal items that host vector tile layers.
You have a number of workflows available to you depending on whether your vector tiled data has custom style resources, whether you want to download many custom styles that you can apply to a number of tile caches, or whether you just want to obtain the default tile cache.
To create a vector tile package (.vtpk file) and vector tile style resources, do the following:
- Instantiate the export vector tiles task and check whether the vector tiles have custom style resources.
- Specify the export vector tiles task parameters for a specific maximum scale and area of interest.
- Export the vector tiles. The vector tile package is populated with vector tiles and the default style resources from the ArcGIS vector tile service.
Instantiate the export vector tiles task
Instantiate the ExportVectorTilesTask using a URL to the portal item that represents an ArcGIS vector tiled layer. Load the task, and upon completion, check whether the vector tiles have custom style resources by checking the hasStyleResources Boolean value.
// Connect to a portal (ArcGIS Online) to access a portal item ("Colored pencil" vector tile layer).
val vectorTiledLayerItem = PortalItem(
portal = Portal("https://www.arcgis.com"),
itemId = "4cf7e1fb9f254dcda9c8fbadb15cf0f8"
)
// Create a new export vector tiles task, using the portal item for the vector tile layer.
val exportVectorTilesTask = ExportVectorTilesTask(vectorTiledLayerItem)
// Check if the vector tile layer has style resources.
val hasStyleResources = exportVectorTilesTask.hasStyleResources
// Choose whether to download both the custom style resources and tiles or just the tiles.
if (hasStyleResources) {
logInfo("The vector tile package has style resources.")
// Download the style resources and tiles. Or download just the tiles.
//...
} else {
logInfo("The vector tile package does not have style resources.")
// Download just the tiles.
//...
}
Specify the export vector tiles task parameters
To obtain a default set of parameters, call the createDefaultExportVectorTilesParameters method and provide an area of interest (polygon or envelope) and a maximum scale. When you provide the maximum scale, you must be aware that there won't be any tiles when the map is zoomed in beyond this scale. If you set the maximum scale to 0, the export will include all levels of detail in the service.
This method returns the set of default parameters, ExportVectorTilesParameters, required to export the vector tiles to a vector tile package. The LODs have been calculated to support the maximum scale that you specified.
// Set the parameters of the export vector tiles task using the geometry of the area to export and its max scale.
val exportVectorTilesParameters =
exportVectorTilesTask.createDefaultExportVectorTilesParameters(
areaOfInterest = envelope,
maxScale = 5000.0
).getOrElse { error -> return@launch logErr(error.message.toString()) }
Export the vector tiles
Obtain a job to generate and download a vector tile package and its default style resources by passing the ExportVectorTilesParameters to the createExportVectorTilesJob() method on the ExportVectorTilesTask class. You must also provide a download path to store the vector tile package and its default style resources.
Run the ExportVectorTilesJob to export and download the vector tile package (.vtpk).
var destinationFolderPath = context.externalCacheDir?.path.toString()
// The destination path (including the file name) for the .vtpk on the device file system.
val destinationPath = destinationFolderPath + File.separator + "myVectorTiles.vtpk"
// Create an export vector tile job with the parameters and the pat
val exportVectorTilesJob = exportVectorTilesTask.createExportVectorTilesJob(
parameters = exportVectorTilesParameters,
downloadFilePath = destinationPath
)
// Start the export vector tile cache job.
exportVectorTilesJob.start()
// If job succeeds, display the map.
coroutineScope.launch {
val vectorTilesResult: ExportVectorTilesResult =
exportVectorTilesJob.result().getOrElse { error ->
return@launch logErr("The job failed to return an export vector tiles result: ${error.message}.")
}
val vectorTileCache = vectorTilesResult.vectorTileCache
?: return@launch logErr("Cannot retrieve the tile cache from the job result.")
// Create a vector tiled layer from the vector tile cache.
val localVectorTiledLayer = ArcGISVectorTiledLayer(
vectorTileCache = vectorTileCache,
)
// Create a basemap with the vector tile layer.
val basemap = Basemap(localVectorTiledLayer)
// Create a new map with the basemap.
// Display the map by assigning it to the mutable map property used by the MapView composable.
map = ArcGISMap(basemap)
}
}
Export the vector tiles with custom style resources
Obtain a job to generate and download a vector tile package containing tiles and associated style resources by passing the ExportVectorTilesParameters to the createExportVectorTilesJob() method on the ExportVectorTilesTask class. The portal item's associated style resources will be downloaded and saved separately. You must also provide a download path to store the vector tile package and a separate download path for the style resources.
Run the job to export and download the vector tile package (.vtpk) and the style resources to the device.
// Create a directory in the app's cache to hold the exported tiles (in a .vtpk) and the custom style resources.
var destinationFolderPath = context.externalCacheDir?.path.toString()
// Create a job with the export vector tile parameters, the path to the .vtpk file, and the path
// to the folder holding the style item resources.
val exportVectorTilesJob = exportVectorTilesTask.createExportVectorTilesJob(
parameters = exportVectorTilesParameters,
vectorTileCachePath = destinationFolderPath + File.separator + "myVectorTiles.vtpk",
itemResourceCachePath = destinationFolderPath
)
// Display map if job succeeds.
coroutineScope.launch {
val vectorTilesResult: ExportVectorTilesResult =
exportVectorTilesJob.result().getOrElse { error ->
return@launch logErr("The job failed to return an export vector tiles result: ${error.message.toString()}.")
}
val vectorTileCacheFile = vectorTilesResult.vectorTileCache
?: return@launch logErr("Cannot retrieve the vector tile cache.")
val itemResourceCacheDir = vectorTilesResult.itemResourceCache
?: return@launch logErr("Cannot retrieve the item resource cache.")
// Create a vector tiled layer from the vector tile cache file and item resource cache directory.
vectorTiledLayer = ArcGISVectorTiledLayer(
vectorTileCache = vectorTileCacheFile,
itemResourceCache = vectorTilesResult.itemResourceCache
)
// Create a basemap with the layer.
val basemap = Basemap(vectorTiledLayer)
// Create a new map with the basemap.
// Display the map by assigning it to the mutable map property used by the MapView composable.
map = ArcGISMap(basemap)
}
// start the export vector tile cache job
exportVectorTilesJob.start()
Export custom style resources
Obtain a job to download any custom style resources associated with the tasks vector tiles by passing a download path to the createExportStyleResourceCacheJob() method on the ExportVectorTilesTask class.
Run the job to export the style resources. Obtain the itemResourceCache property from the ExportVectorTilesResult class.
// Create a directory in the app's cache to hold the exported custom style resources.
var destinationFolderPath = context.externalCacheDir?.path.toString()
// Create a job with the export vector tile parameters and the path to the style item resources directory.
val exportStyleJob: ExportVectorTilesJob =
exportVectorTilesTask.createExportStyleResourceCacheJob(
itemResourceCachePath = destinationFolderPath
)
// Display map if job succeeds.
coroutineScope.launch {
val jobResult: ExportVectorTilesResult =
exportStyleJob.result().getOrElse { error ->
return@launch logErr("The export style job did not return an item resource: ${error.message.toString()}.")
}
val itemResourceCache = jobResult.itemResourceCache
?: return@launch logErr("Cannot find item resource cache.")
}
exportStyleJob.start()
Download image tiled data
You can take image tiled data offline by exporting and downloading the image tiled data as a tile package (.tpk or .tpkx) using the ExportTileCacheTask class. This task requires that the tiled map or image service support the creation of an offline tile cache; specifically, it must enable the export operation. This can be found at the bottom of the service's HTML page. Esri provided basemaps and elevation sources will be swapped for their export-enabled services. To create the tile cache, do the following:
- Generate the default export image tile cache parameters and set any of the properties.
- Export and download the image tile cache using the methods on the
ExportTileCacheTask.
Generate default export image tile cache parameters
Construct a default set of parameters (ExportTileCacheParameters) by passing an area of interest (polygon or envelope) along with the minimum and maximum scale thresholds to the createDefaultExportTileCacheParameters method on the ExportTileCacheTask class.
This method will return a set of parameters for the area of interest and will calculate the levels of detail (LODs) required to support the minimum and maximum scale for the service's tiling scheme. You can adjust these LOD levels or remove some before you download the cache.
val tilesMapServiceURL = "https://tiledbasemaps.arcgis.com/arcgis/rest/services/World_Imagery/MapServer"
// Instantiate an export tiles task with the URL to the tiled service.
val exportTileCacheTask = ExportTileCacheTask(tilesMapServiceURL)
val envelope = Envelope(
xMin = -117.205,
yMin = 34.035,
xMax = -117.148,
yMax = 34.064,
spatialReference = SpatialReference.wgs84()
)
val exportTileCacheParameters = exportTileCacheTask.createDefaultExportTileCacheParameters(
areaOfInterest = envelope,
minScale =20000.0,
maxScale = 5000.0
).getOrElse { error ->
return@launch logErr("Unable to create the default export tile cache parameters: ${error.message}")
}
Export and download the image tile cache
Obtain an export and download job by passing the ExportTileCacheParameters to the createExportTileCacheJob() method on the ExportTileCacheTask class. Run the job to download the tile cache into a tile package that is placed in the download path on the device.
val tileCachePath =
destinationPath + File.separator + "exportAndDownloadTheImageTileCache.tpk"
// Create the job.
val exportTileCacheJob = exportTileCacheTask.createExportTileCacheJob(
parameters = exportTileCacheParameters,
downloadFilePath = tileCachePath
)
// Run the job.
exportTileCacheJob.start()
The tile cache from an exported basemap tile layer can be used in your map or scene.
val tileCache = exportTileCacheJob.result().getOrElse { error ->
return@launch logErr("The export tile cache job did not return a tile cache: ${error.message}")
}
// Create a tiled layer from the local cache.
val tiledLayer = ArcGISTiledLayer(tileCache)
// Create a basemap with the tiled layer, and then create a map with that basemap.
val tileCacheMap = ArcGISMap(Basemap(tiledLayer))
// Display the map by assigning it to the mutable map property used by the MapView composable.
map = tileCacheMap
The tile cache from exported elevation data can be used as an elevation source in your scene.
// Create a tiled elevation source using the tile cache.
val localElevationSource = ArcGISTiledElevationSource(tileCache)
// Create a surface and add the elevation source.
val elevationSurface = Surface().apply {
elevationSources.add(localElevationSource)
}
// Add the surface to a new scene.
val newScene = ArcGISScene(BasemapStyle.ArcGISImageryStandard).apply {
baseSurface = elevationSurface
}
// Use the new scene to update the mutable scene property of the SceneView composable.
scene = newScene
When creating an offline tile cache from a tiled service, consider the following:
- The export tiles operation used to generate tile caches is only available with services hosted on ArcGIS Server 10.2.1 or later.
- Estimation of tile cache size is not available on ArcGIS Online hosted tiled services.
- The time required to create a tile cache varies depending on the extent requested, the number of levels requested, the network connection speed, and so on. Use the
createEstimateTileCacheSizeJob()method on theExportTileCacheTaskclass, which returns anEstimateTileCacheSizeJobto get the approximate size of a tile cache for a specific set of parameters. Try generating a smaller tile cache to get an idea of how long caching will take when planning a large offline data capture event. - There is a limit to the number of tiles you can generate in a single request. When generating a tile cache from an ArcGIS Online basemap, there is a limit of 100,000 tiles per request. Read more on this in the ArcGIS REST API documentation. Organizations that use their own ArcGIS Server to host an offline tile cache can configure the server's
maxvia the administrator account to change the default limit of 100,000 tiles.Export Tiles Count