GAP Help
The Groundwater Assessment Platform (GAP) hosts information on geogenic contamination of groundwater by arsenic and fluoride. It provides the possibility to share data, case studies and field experiences as well as to interact with other users and create probabilistic maps for any area on the globe. The site has two main sections. Maps & Tools (blue frame in Figure 1) is where you can display and print existing data and models as well as manipulate and model your own data and create risk maps. The GAP Wiki, which contains diverse information on geogenic contamination, can be accessed via the Documentation link on the front page or from a link on the top bar (red frame in Figure 1).
The Help section provides instructions for using the Maps & Tools section.
Contents
Viewing geospatial data (without registration)
All of the publicly available maps and data can be viewed and printed without registering on the site. Clicking on 
opens a list of all available layers. Clicking on 
prints the map currently being viewed as a PDF.
Viewing geospatial data and developing models (with registration)
To be able to upload your own data and create models, you must register or log in (1).
The main features of GAP Maps & Tools are shown in Figure 3. Clicking on the toolbar (3) displays the different features of the site (see inset in Figure 1). These are explained in detail in the sections: Layers, My Layers, Statistical Analysis, Communities, Manage Account, Print.
Layers (5) contains all available layers.
Map Layers (4) lists all layers that have been selected. Here you can change the opacity and view the legend. In the lower right corner (6) you find the zoom function as well as the Info Cursor which lets you identify the data of a certain pixel.
In case you have questions or require help while using the site, you can click Help in the top bar to open GAP Help, which explains all of the features of GAP Maps & Tools.
Clicking 
anywhere on the page will always direct you to the corresponding Help site.
Register
You can add a new account with your email address. Make sure to read the 'Legal notice and disclaimer' before you click on Register.
GAP Database
Here all available GAP Layers (categorized based on geology, climate, soil, etc) are listed as depicted in Figure 2. There are 3 data types, "coverage", "polaygon" and "point".
To add a layer to the map, double click on the layer name. To see the layer Information (source and description), press 
next to the layer.
| Data Type | Icon |
|---|---|
| Coverage | 
|
| Polygon | 
|
| Point | 
|
Map Layers Panel
The Map Layers panel lists all layers that have been added to the map previously. By right-clicking on the layers you can rearrange layers, remove layers and zoom to the extent of a certain layer (Figure 3)
| Figure 5: Map Layers panel collapsed (left), Map Layers panel expanded (center) and Tools (right). | File:MapLayers.JPG | File:MapLayersTools.PNG | File:MapLayerTools.PNG |
Private Data
The window My Layers shows all layers uploaded by the user. Additionally it includes functions to add, remove, share, visualize and manipulate the symbology of layers.
Add Layer (upload layer)
Provides functions (tools) for uploading spatial layers (data). Click here to get to the site describing all necessary details.
Remove Layer
To remove a layer, select it in the table and click Remove.
Provides tools to share/un-share a layer publicly and/or with an individual user or a community. Click here to get to the site describing all necessary details.
Visualize Layer
To visualize a layer (add layer to map) either double click on the layer name in the table, or select layer in the table and click Visualize.
Layer Symbology (style)
Provides functions (tools) for changing the layer symbology. Click here to get to the site describing all necessary details.
Statistical Analysis
The Statistical Analysis section provides tools and functions for developing statistical models and probability maps. Click here for detailed information.
Community Data
The Community window lists all communities of which the user is a member. The layers are categorized by community names. Clicking Create will open a window where you can initiate a new community. Selecting one community and clicking Remove will remove the community. This is only possible if you have administrator rights. You can see the details on user rights by clicking Details and if you have administrator rights change details by clicking Edit. When you click Layers a separate window will open that lists all communities you are part of and the respective layers that are accesible to this community. You can such a layer to the map by double clicking on the layer name.
Manage your Account
Clicking 
will lead you to your personal Account Settings. You can change your password and delete your account.
Print Map
After you have selected an area on the map you want to print, click on 
to open the interface. Choose a Map Title (which will be printed on your final map), the page format (Landscape, Portrait) and the resolution (DPI). Note that when visualizing the backround map, the resolution is limited to 90 DPI). Then click Submit.
Help
To get help througout the site press .
