THL Toolbox > Places & Geography > THL Interactive Maps
Contributor(s): David Germano, Tom Benner
This page documents how to use the THL Interactive Maps of Tibet and the Himalayas.
THL’s interactive maps are created from “GIS” coverage, which basically means databases of geographic points and regions keyed to latitude and longitude values from which various maps can be dynamically created. In simple terms, a geographic point – for a village, a mountain, a monastery – is entered into a database with a corresponding latitude and longitude value to mark the “point.” Likewise, a geographic region – for a county, a cultural area, a nation – is entered into a database with corresponding latitude and longitude values that mark the boundary of the region to trace a “polygon.” GIS software then enables various maps to be created from this database of points and polygons. The type and extent of points and polygons documented in the database is typically referred to as GIS “coverage.” The diverse maps that can then be created by the user from this coverage hinges upon which types of features are chosen to display in a given view, with each type of feature referred to as a “layer.” Thus, for example, one might choose to view a GIS map with a layer providing polygons for contemporary administrative units, a layer with polygons for medium-size to large lakes, or a layer providing points for large monasteries. Multiple layers can be selected. Thus, by mixing and matching various layers, users can create a wide variety of maps which can then be printed, downloaded, and so forth.
At present, any geographical feature within THL’s Place Dictionary can be immediately visualized on the Interactive Maps, with the corresponding point or polygon highlighted in yellow. Users can then customize the overall map by switching different layers on and off. We are currently working on improving the system so that users will be able to click on a given point or polygon on the Interactive Maps, and go directly back to the corresponding Place Dictionary entry. Once that improvement is in place, the Place Dictionary and Interactive Maps will be a powerful integrated system for delivering information and visualizations of Tibetan and Himalayan places.
These maps have four distinct aspects: the actual map, controls, tools, and legends.
The map of course is the actual map.
The legend provides a key explaining the different visual aspects of the map and the types of geographical features to which they correspond.
The tools at present are minimal and basically allow for focusing on different regions of the map, and zooming in and out.
- Click the magnifying tool on the left to activate it. When active, where you click on the map will be zoomed in and centered. You can do this repeatedly to zoom in in stages.
- Click the pan tool (visually a hand) in the center to activate it. When active, where you click on the map will be centered in the window.
- Click the negative magnifying tool on the left to activate it. When active, where you click on the map will be zoomed out and centered. You can do this repeatedly to zoom out in stages.
Controls provide the means to make turn on and off various layers – each layer corresponding to a type of geographical feature – as well as change the language of the geographical labels which display.
- In order to make a layer visible or invisible, click the box beside it and then click the “Refresh” button.
- To view labels in a given language, click the corresponding label box and then click the “Refresh” button. Note: the layer needs to be visible in order for any given label layer to appear.
- Although it may seem that only some of the names for features appear when the labels are active, this is because they are set not to overlap. If you zoom in far enough, they will appear.
This resource is geared toward a popular use of GIS-derived interactional maps.
In the “Browse” section of the menu and in the other tools that list feature types (for example, the “Feature type” field in the “Search” section of the menu), the only feature types that are listed are ones for which we have features with geographic data. The two numbers in the parentheses following a feature type name are, respectively, the number of features for that feature type that have geographic data and the total number of features for that feature type.
The preceding discussion is geared toward a popular use of GIS-derived interactional maps. For specialists, however, GIS coverages can be employed for powerful analytical functions. For example, searches can be done that request the relationship between different layers, and then cartographic representations can be derived of the query results. Thus, one might ask to see all monasteries above a certain size, and within fifty meters of a lake, and then visualize this on a map against a specified background of layers. Specialists should consult the THL GIS Portal for details.