This tutorial illustrates how the web map can be used to undertake complex queries. The tutorial uses the Turkey web map, selects all wheat trial sites in areas with less than 400mm annual precipitation and exports the selected trial site information to excel.
- Open the Turkey Wheat Atlas web map. By default the “wheat trial sites” layer and the “wheat production” layer will be visible.
- De-select “wheat production”, by removing the checkmark in the “visible” box. Select “Precipitation Annual” by clicking in the “visible” box next to the layer. Make “Precipitation Annual” active by clicking in the “active” button next to the layer. Click Refresh Map button (NB: You might have to use the scroll bar at the side of Layers to see this button at the bottom).
- The map will now display wheat trial sites and annual precipitation. Like this:
- Click on the “Query” tool located on the toolbar (at left-hand side of map). This will open a query window below the map.
- Create the query as follows: Select “Precip” from the “Field” list. Select “<” from the “operator” list. Type 400 into the “value” box. Click “Add to Query String” button – you will see Precip < 400 appear in box. Click “execute” button. On the map you will see all areas with annual precipitation < 400 mm highlighted.
- Click on the “Buffer” tool located on the toolbar. This will open a “Buffer” display below the map.
- Select “wheat trial sites” from the “Highlight features from” list. Leave distance as 0 (i.e., trial sites must be entirely within selected annual precipitation zone). Select “Display Attributes” option. Click “Create Buffer” button. You will see a table with data from 9 wheat trial sites visible – these are all the trial sites within the area where annual precipitation is < 400 mm.
- To see the selected sites on the maps. De-select the “precipitation annual” layer by removing the “visible” checkmark next to it in Layers. Click on the “Refresh Map” button. You will now see the selected sites (those with annual precipitation < 400 mm) highlighted on the map.
- To export the site data to excel. Right click in the Wheat Trial Sites table below the map. Select the “Select All” option from the list. Right click again and select the “copy” option. Open Excel and paste. All the site tabular data will now be in excel.