Maps

The main purpose of this application is to allow people to identify suitable environmental site locations. In order to do that, a hydrological model for the area of interest can be generated by creating a map in an area of interest.

Important

A minimum of two datasets is needed to create a map:

  1. A digital elevation model

  2. A population raster

In the application, default datasets are available such that a map can be created at almost any place in the world. However, if available, individual datasets can be uploaded to improve the quality of the map, as described below.

Furthermore, the following layers can be added to improve the quality of the map:

  1. Streams and rivers

  2. Lakes

  3. Barriers and exclusion areas

  4. Sewage lines

To aid site selection, a set of tools will be available in a later version of the application. For the time being, sites can be manually added to a map, however, no watershed is delineated for those sites.

Map creation

Maps can only be created where a user has permission to create maps.

New map

To create a map, you need to be logged in. Click on ‘New map’.

../../_images/new_map_button.png

  1. You can search for a location here.

  2. Select the DEM here and population rasters here. The default rasters are ALOS30m for the elevation raster and WorldPop unconstrained for the population raster. FABDEM and SRTM30m as well as WorldPop constrained rasters are available as well. If you upload your own DEM or population raster, they will appear in the list here.

  3. If you want more information about the source that is selected, click the ‘i’ icon.

  4. To upload your own DEM or population rasters, click on the ‘+’ icon.

Important

The DEM and population rasters need to intersect, otherwise you will get an error. Upload limits apply: 2GB for population and DEM rasters. Additionally, they need to be in the EPSG:4326 projection.

../../_images/new_map_creation_window.png

Different error messages will let the user know if an area cannot be selected. For instance, there are minimal and maximal extent warnings:

../../_images/area_too_large.png

Set map extent

Once the correct extent has been identified click on ‘Set Map Extent’.

../../_images/set_map_extent.png

  1. Select a location from the list - this is needed such that the map obtains automatically a location attribute. Note, you can search this list if you have multiple names.

  2. Set a name for the map - this can be how you refer to this map and it will show up with this name in your workspace.

  3. If needed, provide a description.

  4. Click ‘Save Map’.

../../_images/map_creation.png

  1. On the popup, click ‘Confirm’.

../../_images/map_creation_confirm.png

Important

Once you have confirmed, map processing will start. As population and DEM data needs to be fetched, this process might take a while. A status is indicated.

../../_images/map_processing_dialog.png

Important

The most basic version of a map has now been created. To refine the map, more layers should be added if possible, such as sewage lines, rivers, exclusion areas etc.

Map viewer

The map viewer is the part of the application where site selection happens.

  1. The left panel allows to show and hide information (can be collapsed via the cross)

  2. Main information such as map name, processing date, editor and description can be consulted here

  3. Show / hide population and elevation input

  4. Show / hide layers and sub-layers (note, the ‘Hydrology’ section contains calculated layers, meaning those are the resulting layers from the map processing - these layers never show in the map editor)

  5. Show the individual sites - the 3-dot menu can be used to zoom to a site

  6. Show / hide the site creation helper tools - see Site creation helper for details on this

../../_images/map_viewer_1.png

Site creation helper

This tool is to aid selection of sites.

Draft site generator

  1. Open the tool via the button

  2. Delineate a watershed (i.e. select a potential site) via the pin drop or entering coordinates

  3. This adds a new ‘Draft Site’ to the menu below

../../_images/site_creation_helper.png

Coverage parameters

To aid the selection of sites, the coverage parameters can be utilized. A population or area criteria can be set to filter the possible locations.

For instance, if a site should sample between 10k and 50k people, enter these values in min and max and click on ‘Find’. This will highlight the areas to sample from. This works analogous for area.

../../_images/site_coverage_parameters.png

Important

Note, this works currently only for open sewage delineation.

Manage draft sites

All draft sites created will be added to this menu. From here you can:

  1. Remove a draft site

  2. Bring a watershed to the front (if hidden by an overlapping watershed for instance)

  3. Highlight it on the map

  4. Turn one or multiple draft sites into sites via the map editor (note, all site metadata can be added in the map editor later)

  5. Export the draft site as a GeoJSON or CSV

../../_images/manage_draft_sites.png

Hydrology layers

  1. The ‘Drainage Lines’ show the predicted flow of the water.

  2. If a site has been created, the ‘Site catchments’ shows the areas that contribute to a site.

  3. Drainage basins are the individual areas that are used to calculate site catchments.

../../_images/hydrology_layers.png

See Premise for explanations of the drainage lines, catchment and drainage basins calculations. See also Map processing parameters to understand the parameters for map processing.

Map edition

Map edition allows to add more details to a map. Sewage lines, exclusion zones, rivers, etc can be added via map edition.

Important

It is recommended to add as much detail as possible to a map to make it as accurate as possible. The first thing to improve a map will be to add OSM data. This data is automatically fetched for the sources where OSM data is available (such as rivers and lakes).

Start map editing

There are two ways to start editing a map:

  1. Via the workspace:

../../_images/edit_map_workspace.png

  1. When already on the map:

../../_images/edit_map_mapview.png

Change the map extent

Important

Works only in edit mode

The extent of a map can be changed within limits:

../../_images/modify_extent.png

Reordering layers

It is possible to reorder how the layers appear (ie which layer should be on top of another layer etc). To reorder the layers, click the corresponding toggle button and drag the layers into the order you would like.

Important

Reordering requires map processing afterwards to be effective. Additionally, the hydrology layers can be adjusted here, even though these layers are only visible in the map viewer (see Map viewer)!

../../_images/reorder_layers.png

Add or remove a source to a map

Important

Works only in edit mode

Using the ‘+’ icon, a new source can be added to the map.

../../_images/add_layer.png

Once a source has been added, it can be edited or removed. Some sources allow import of data.

Important

Import of data is always a drop and replace, meaning that when you load a shp file into a layer, all existing data of this layer will be replaced by the data you import!

../../_images/remove_edit_layer.png

Sites

Important

Works only in edit mode

Sites are point features.

  • Adding manual sites source

  • Adding ODK sites source - the ODK import will need a separate setup

  • Adding WebIFA site source as read only

Adding a manual site source allows to:

  • Add sites manually (see Editing)

  • Upload an existing layer in either shp file or geojson format

../../_images/add_sites.png

Hint

When uploading a file, please make sure you respect the data model.

Rivers

Important

Works only in edit mode

Rivers are line features.

  • Adding manual river source

  • Adding OSM river source

  • OSM data can be refreshed, in case new data is available on OSM

Sewage lines

Important

Works only in edit mode

Sewage lines are line features.

Important

Sewage lines can have two main attributes that are important for map processing: Type (open or closed) and Trunk (true or false). For further explanation see Sewage line metadata

  • Adding manual sewage line source

  • Adding ONA sweage line source - the ONA import is currently setup to pulling ONA data from AFRO.

  • Adding ODK sewage line source - the ODK import is currently setup to pull data from a Novel-T ODK server.

  • Adding OSM underground sewage channels

Adding a manual sewage line source allows to:

  • Adding sewage lines manually (see Editing)

  • Upload an existing layer in either shp file or geojson format

Hint

When uploading a file, please make sure you respect the data model.

Barriers

Important

Works only in edit mode

Barriers are line features.

Adding a manual barrier source allows to:

  • Adding barriers manually (see Editing)

Exclusion zones

Important

Works only in edit mode

Exclusion zones are polygon features.

Adding a manual exclusion source allows to:

  • Adding exclusion zones manually (see Editing)

  • Upload an existing layer in either shp file or geojson format

Lakes

Important

Works only in edit mode

Lakes are polygon features.

  • Adding manual lake source

  • Adding OSM lake source

  • OSM data can be refreshed, in case new data is available on OSM

Adding a manual lake source allows to:

  • Adding lakes manually (see Editing)

  • Upload an existing layer in either shp file or geojson format

Editing

All layers can be edited. Some editing features are universal:

  1. Selection tool - this is active per default and can be used to select individual features

  2. Consider / ignore for processing - this tool can be used to mark / unmark features for map processing (for instance, if there are some features on map that you think should not be considered for map processing but you still want to keep them, you can use this tool)

  3. Delete - this tool allows to delete features from a layer

  4. When drawing a shape, you can always use the ‘Undo’ button which will undraw the last point drawn

  5. Snapping allows to connect sites, sewage lines, rivers etc properly

../../_images/universal_editing.png

The editing dialog depends on the layer (point, line or polygon layer).

Point layer editing

This is used to add sites. Sites / points can be added via this tool (or via import, see Sites):

../../_images/site_addition.png

Adding sites manually triggers a dialog where metadata can be added.

../../_images/site_metadata_dialog.png

In this dialog, the only required field are the coordinates.

Note that you can add composite sites via the toggle at the top. There are two types of composite sites:

  1. Geospatial composite site (one site name that corresponds to several nearby sampling locations)

  2. Temporal composite site (sampling the same location over the course of several minutes or hours)

For the geospatial composite sites, up to three geospatial coordinate pairs can be entered. The main site is depicted with a star icon, the sub-sites are slightly smaller and without a star.

../../_images/composite_site_geospatial.png

The temporal composite site is depicted with a clock on the site icon.

../../_images/composite_site_temporal.png

Line layer editing

You can draw lines via this tool:

../../_images/line_feature_edit.png

Click on the tool to draw. Double click to finalize the shape. Once you finalized the shape, you can still edit it (drag the vertices to the right place). You can always edit a feature as long as the vertices show. If you select multiple features at the same time, you can batch delete or batch consider / ignore them for processing.

../../_images/vertices_edit_mode.png

Hint

You can use the ‘Invert flow direction’ tool to change the direction of drawn lines.

../../_images/invert_flow.png

Polygon layer editing

You can draw polygons via this tool:

../../_images/polygon_feature_edit.png

Click on the tool to draw. Double click to finalize the shape. Once you finalized the shape, you can still edit it (drag the vertices to the right place). You can always edit a feature as long as the vertices show. If you select multiple features at the same time, you can batch delete or batch consider / ignore them for processing.

../../_images/polygon_vertices_edit_mode.png

Metadata editing

Hint

Features that are added to the map can be clicked on to see corresponding metadata.

For instance:

  1. Click on the added WebIFA site

  2. The dialog will open with the metadata for this feature

../../_images/metadata.png

Some of the metadata can be edited.

Important

Works only in edit mode

  1. Click ‘Edit’ of the layer you want to edit the metadata for

  2. Click on the feature you want to edit

  3. Click on ‘Edit metadata’

../../_images/edit_metadata_1.png

../../_images/edit_metadata_2.png

Important

The metadata for sewage lines is important for map processing. See Map processing parameters to better understand how.

Remote source editing

Remote data sources such as OSM or ODK cannot be modified at their source, since this data is remotely sourced and there is no push from ES to those remote sources. However, the data can still be modified in ES, though those modifications will then be stored in a manual layer.

To modify ONA (or other remote) collected data:

  1. Go into the edit mode of the ONA sewage lines

  2. Start editing the lines as you would in another layer

  3. Note the dialog that notifies that the modifications will be copied

  4. Once you are done editing the layer, clicking ‘Save’ will show you the confirmation popup

  5. After confirmation, the modified lines are now hidden in the ONA layer but present in the manual sewage layer

../../_images/ODK_edit_1.png

../../_images/ODK_edit_dialog.png

../../_images/ODK_edit_dialog_confirm.png

../../_images/ODK_edit_manual_layer.png

Important

If you refresh any remote source before saving this layer first, all features in their original state are back, even the ones that were hidden previously. They will have to be manually hidden again after a refreshment. This is not the case if the layer has already been processed once, in which case the layer remembers the previous state.