News — 25 September, 2017
Export Tool | 01 Selecting Area of Interest
This blog focuses on how to 'Select Area of Interest', and is the first in a series of ‘Learn Export Tool’ posts following the launch of the revamped tool on the 18th September 2017. Three more blogs in the series will cover the different available ‘Data File Formats’, how to ‘Customise Map Features’ and examples of ‘Applying Exported Data’.
The Humanitarian OpenStreetMap Team (HOT) Export Tool allows users to create custom OpenStreetMap (OSM) extracts anywhere in the world, by selecting an area of interest, map features and file formats. Within minutes, up-to-date OSM data is exported, filtered and converted.
There are multiple ways an Area of Interest (AOI) can be selected through the Export Tool. This includes the ability to type and search, specify the coordinates of a bounding box, draw a bounding box, free draw a polygon, use the current view or upload a geojson file.
This blog is the first in a series of ‘Learn Export Tool’ posts following the launch of the revamped tool on the 18th September 2017. Three more blogs in the series will cover the different available ‘Data File Formats’ (October 2nd), how to ‘Customise Map Features’ (October 9th) and examples of ‘Applying Exported Data’ (October 23rd).
Figure 1. Log In
Figure 2. Create Tab
Once you are ‘Logged In’ to the HOT Export Tool (figure 1), the ‘Create’ tab will become available (figure 2). The ‘Create’ tab is where you will set up your export, by describing it on the left hand side (figure 3) and selecting your AOI with the map on the right hand side.
Figure 3. Describe Export
There are 6 ways to define an AOI for your export. The first and second, use the search bar, which can either find a place by typing in its name and selecting it from the options below (figure 4), or by defining the bounding box coordinates (figure 5). The minimum X, minimum Y, maximum X and maximum Y (West, South, East, North) coordinates of a country can be found in a CSV list provided by the Humanitarian Data Exchange (HDX).
Figure 4. Place Name
Figure 5. Place Coordinates
The third and fourth way that an AOI can be selected in the Export Tool, is by either drawing a bounding box by selecting the ‘Box’ option from the column of Tools on the right of the screen (figure 6). Or you can free draw a polygon directly on the map by selecting the ‘Draw’ tool (figure 7).
Figure 6. Bounding Box
Figure 7. Draw Polygon
The last two ways in which an AOI can be selected is through the ‘This View’ tool on the right hand side of the map, which captures the extent of the map’s current view (figure 8), or by the ‘Import’ tool which enables you to upload a polygon of the area (figure 9).
Figure 8. Current View
Figure 9. Load Polygon
The imported polygon must be a GeoJSON file in WGS84 geographic coordinates. One of the ways to create a GeoJSON file is to use the geojson.io site (figure 10). Once the area has been selected in geojson.io, copy the text in the box to the right, paste it into an editor of choice, such as Atom and save your GeoJSON file (figure 11).
Figure 10. geojson.io
Figure 11. GeoJSON File
The GeoJSON file needs to be edited slightly in order for it to be accepted by the Export Tool. Please note that the file can not be multipolygons. In the most simplest form, the file only needs to state that it is a “type”: “Polygon” and list the coordinates of the points/nodes that identify the area (figure 12). The GeoJSON file will then successfully be parsed by the tool and used to specify the AOI (figure 13).
Figure 12. Edited GeoJSON
Figure 13. Upload Successful