The above picture might be enough to understand the map control. The possibility to edit objects and add new ones will be discussed in the next article. Any questions, of course, are welcome.
Base and overlay layersThe base and overlay layers serve as a topographic map background. The difference between them is that the base map can be only one, whereas overlay maps can be turned on more.
The Arctic area is probably best mapped at the ESRI World Topo Map (e.g. concerning geographical names), the highest quality satellite map is probably HERE.
Topic layersThematic layers represent "Franklin" map content. The individual objects in these layers are described by several attributes (see below, the "Objects" section). When you click on the object, an information window for the object will pop up. The map contains the following "official" layers:
- Franklin expedition
- Previous expeditions (before 1845)
- Rescue expeditions (after 1847)
- Monuments and museums
Layers are distinguished by colour when viewed on a map.
ObjectsFrom a geometric point of view objects can be points, lines, and areas (polygons).
Each object must have a title and a category (see below). It can also contain a more detailed description, picture (photo) and max two related links.
- ship (floating)
- sledge (land parties)
- human remains
- sighting (Inuit reports)
- geography (geographical names)
- ship route
- land route
|Icons in the order listed above (left to right and top to bottom). Author: Gustav Vávra|
Technical backgroundFor non-experts in IT: Do not worry if this section is a total mystery to you. It should not prevent you to use the map.
The "Franklin" objects are retrieved in the GeoJSON format from the database. The output from the database in this format (used as a data source for the map) can be viewed at https://com.franklinova-expedice.cz/db/readfranklin.php.
Note: the map application is universal, most features and content sources are set up by configuration files, i.e. it can be used for any map content, not just for the Franklin's expedition. However, relevant documentation for such deployment is not ready yet.
- Object clustering. There is a lot of points in some places (e.g. London). It would be better to display only information about number of objects in such places (instead of objects itself) in small map scales.
- Better display of geographical names (category "geography"). Name labels are currently hard.
- Help for object categories (see list of icons above).