Overlay Layers
The Data Layers tab lists all of the data layers that will appear under the 'Overlay Layers' tab in the user view.
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The Data Layers tab lists all of the data layers that will appear under the 'Overlay Layers' tab in the user view.
Last updated
Note that this section will evolve over the coming months. Currently, you can add Overlay Layers to your SeaSketch by directly uploading files in the form of shapefiles, geojson, flatgeobuffs, and geoTIFFs. You may also add Esri dynamic map services, feature services and image services, and hosted GeoJSON and vector tiles. In the near future, you will also be able to add WMS layers from GeoServer, MapServer or other map servers.
Notice that you can add Overlay Layers and Maps. Think of 'Maps' as base maps and 'Overlay Layers' as those which appear on top of base maps.
Data layers do not need to be in any particular datum or projection. SeaSketch will project your data for you into WGS 84 Web Mercator Auxiliary Sphere. If you are using a shapefile, make sure that all of the necessary files are zipped up together and that no spaces occur in the file name. Here, I have zipped up the following files
FSM_12nm_Territorial_Sea.cpg
FSM_12nm_Territorial_Sea.dbf
FSM_12nm_Territorial_Sea.prj
FSM_12nm_Territorial_Sea.sbn
FSM_12nm_Territorial_Sea.sbx
FSM_12nm_Territorial_Sea.shp
FSM_12nm_Territorial_Sea.shp.xml
FSM_12nm_Territorial_Sea.shx
into one zip archive: FSM_12nm_Territorial_Sea.zip. If you wish to practice using this file, you may download it here.
To add your layer (a zipped shapefile, flat geobuff, geojson or GeoTIFF), simply drag and drop the layer onto the map. (You may also choose "Edit > Add Data > Upload spatial data files" and navigate to your file.) Depending on the size of your file, it may take a few seconds for it to upload, queue and tile. When complete, it will be turned on.
You can upload multiple files at once by simply dragging and dropping them all at once. If you are uploading shapefiles, each shapefile will need to be contained within its own zip archive.
At the moment, you add Esri map services (dynamic map services, feature services and image services). In future releases, we will add the ability to add WMS services from GeoServer and other map servers. To add an Esri map service, choose Edit > Add Data > Esri ArcGIS service.
Map services can be added as base maps and, in some cases, Overlay Layers. Esri has a number of great map services that can be added as base maps including one for World Imagery. The URL for this is (at the time of this writing):
Copy this URL and paste it into the service dialog box.
When you browse for a specific service, you're likely to see other services that are available on the same service. This is quite handy! Esri has a number of great map services you might find useful. Choose the one you want and click ‘Add service to project’.
Tile services like this one can be added as a basemap or an overlay layer.
To edit a layer, right click on the layer name and choose Edit. This will bring up a dialog box that lets you edit basic settings, interactivity and the layer's style.
Enter the name of the layer under Title. It's good practice to have a simple name, without underscores or unecessary characters, that is easy to read and understand by anyone without technical knowledge.
Enter a simple attribution that will show up at the bottom of the namep when the layer is turned on. This layer came from MarineRegions.org.
These settings are used to control which users can see the layer. Here, I've set it so that anyone in the public can view the 12 nm Territorial Sea layer. When building and testing your site, you may find it useful for only Administrators to see it, then publish it layer for public viewing. If you're dealing with highly sensitive layers, you may want to limit its viewing to a selected group, defined under the Users & Groups tab.
To allow users to download this layer for use in a desktop GIS, toggle “enable data download” on. It is very important to keep in mind the data sharing agreements that you have signed or any limitations to sharing that the data provider has stipulated.
At the bottom of the Settings tab, you'll find a lot of useful information about the layer you've uploaded. Of particular interest here are the list of attribute names in the Columns list at the bottom. You can make use of this in the Interactivity section below. Hover your cursor over the elipse (...) next to an attribute name to see a list of potential values.
The settings under the Interactivity tab give you some control over values that may appear when you click on a layer or hover over a layer feature. A Banner is short text that can be displayed toward the bottom of the map when the user hovers over features. Tootips are short text displayed next to the mouse cursor when you hover over a feature. Popups appear when you click feature.
Note that Tooltips and Popups can be enhanced with simple HTML tags. We will provide more information on this feature in future updates to our documentation.
Vector layers can be syled using MapBox GL Style Layers. When you initially upload your vector data, SeaSketch determines the geometry type (point, line, polygon) and applies generic styling. Click on the color boxes to change colors and edit the text for more sophisticated styling.
In future releases, we may include templates for you to use with common layer types.
The order that layers appear in the list may be altered by simply dragging and dropping any given layer up or down the layer tree (i.e., list).
Click the "Add Folder", give your folder a name, and then drag and drop layers into the folder to add some thematic organization to your layer tree.
Access controls for folders work the same as layers. Right click on a folder and choose "edit" to see your options. Folders may be accessible to the Public, Admins Only or by a Group that you have created in Users and Groups.
Note that folders can be configured such that layers may be checked-off only (i.e., so users cannot turn all layers on at once), or where the folder cannot be expanded to see individual layers (all layers are turned on at once), or such that only one layer within the folder may be turned on at once. Experiment with the various folder types to see how they work.
Folders, just like layers, may be ordered by simply dragging and dropping them to different locations within the layer tree.
The Z-Order refers to how layers appear on top or beneath one another. Click the dropdown list next to "View" to see the default ordering of your layers. To move a layer so that it appears on top of another one, simply drag and drop the desired layer toward the top of the list.
Before end users can see the layers that you have added to your project, you need to "publish" the layers. Clicking the "Publish" button, you'll see this warning:
When ready, click "publish" and then return to the project view by clicking the "Back to Project" button to ensure everything looks good from the end-user perspective.
Note, you will need to refresh your browser after returning to the project view in order to see your changes!
In SeaSketch, "maps" refer to base maps that are authored in MapBox and then imported into SeaSketch. You will need to create a MapBox account, create Mapbox style, publish it and then add the URL to your SeaSketch project.
In Data Layers, choose Maps > Add New Map > By URL > and past the link below into the field that says Style Location.
mapbox://styles/seasketch/clhao1xum01w901qm2wkd06tc
Select an area of the map to create a thumbnail.
After capturing and saving the thumbnail, the new map will be viewable by all users. They do not require "publishing" as do data layers shown above.
