Location Data in WASH Programmes

Location data is now extremely easy to collect using smartphones. There are also many sources of high quality location data online. Using freely available tools it is relatively simple to visualise this data and use it in humanitarian programmes.

Location data has been used in Oxfam WASH programmes for:

• Understanding where affected populations are.
• Managing water trucking locations.
• Collecting locations of infrastructure (for example latrines) that has been built. This can be used for:
  • Checking the coverage/access to the infrastructure,
  • Accountability and audit.
• Coordinating work with others through the WASH Cluster.
• Design of infrastructure such as water distribution networks

It is good practice to collect location data in WASH programmes, for 1) reporting and accountability, and 2) improving the response based on the data collected.

Always follow Oxfam’s Responsible Program Data Policy. Consider the sensitivity of the data – if any personal data is collected or any information which you, the organisation, affected people, or authorities would not like to make public then a secure system will need to be put in place.

Case studies of where location data has been successfully used in programmes include:

Collecting and Using Simple Location Data

Simple Data collection

In open areas the accuracy of the data collected using a smartphone will be good enough for many purposes. The accuracy of elevations captured by GPS will not be good enough to design water distribution networks. Handheld GPS’s may have higher accuracy than smartphones, but are much more difficult to use. Recent high end smartphones can contain dual frequency GPS which can be used if high accuracy is important. Survey-grade GPS systems are available for very accurate data, but these would normally only be used by surveyors.

When collecting data using a smartphone either:

1. Use a mobile data collection/survey tool. All mobile survey tools have the capability to collect location information. This information can then easily be collected across a team of people using the same app, and then downloaded into a single excel file. Whilst there are multiple systems available, Oxfam’s ICT team have recommended SurveyCTO. You may contact Oxfam’s ICT team for more information, or often this will already be in use by the MEAL team. For those who cannot access SurveyCTO, Kobo Toolbox is a good free alternative. Both of these tools allow the collection of lines and areas as well as a point of the current GPS position. Using a mobile survey tool is a great solution particularly when you want to collect additional information about each location visited, and when a team of people will be collecting the information.
   For more information about mobile data collection tools Oxfam’s Mobile Survey Toolkit is recommended.
2. Use a GPS App. For ad-hoc data collecting, many GPS apps are available which can create waypoints or tracks. Some good starting places for free Android apps are:
   • My GPS Coordinates. A very simple app which allows you to save coordinates, then later export to your computer.
   • SW Maps. More powerful, although more complicated, this app allow you to create points, and tracks and better organise your points into ‘projects’. It allows you to also distribute location data to your team which they can all view and use in the field on this app.
3. Use an infrastructure mapping tool. For infrastructure where you would like to keep track of over time – for example water point or latrine functionality – regular data collection tools are less well suited to this. Tools such as mWater allow the tracking of water point status. Whatever tool is used, a coding system will be necessary for the infrastructure.

Data Sources Online

OpenStreetMap (OSM) is like Wikipedia for maps. It is updated by volunteers, and often has the best maps in remote areas that may be less documented on commercial mapping services like Google Maps. It is often included as the base data in other applications. It is possible, and relatively easy, to update the map yourself. Volunteers will also often update the map using satellite data in response to humanitarian emergencies.

The Humanitarian Data Exchange is a place for humanitarian organisations to share information. For many crises and locations it contains a wealth of GIS data.

Simple Mapping and Data Visualisation

Google Earth is a great tool for visualising data. It is easy to use, has fantastic satellite imagery freely available, good quality elevation data, and it’s possible to import data from a variety of sources. It is also possible to prepare maps for printing or export files out to be shared with others or use in the field on a mobile app. Google Earth Pro for Desktop is free to download.

Some of the key ways to input data into Google Maps are:

• Manually dropping waypoints. Whilst useful for noting features form the satellite imagery, it’s not recommended to add lots of surveyed points using this as errors are likely to be made with all the typing.
• From Excel spreadsheets. If you have data already in an excel spreadsheet, you can easily load this into Google Earth. This is often the case after using a survey tool, for example. To do this save your excel file in .csv format. This video explains the process:

• From .kml / .kmz files. These are the ‘native’ file types of Google Earth. Many mobile GPS apps (including My GPS Coordinates and SW Maps mentioned above) can export data in .kml format, meaning that it can be directly opened in Google Maps.
• From GPS devices directly and .GPX files. This is particularly useful if using dedicated handheld GPS devices. A tutorial from Google about how to import files directly from a handheld GPS is available.
• From Shapefiles and other GIS formats. Google Earth can also open a variety of other formats that are commonly used for sharing GIS information.

Advanced GIS

QGIS

QGIS is a free open source GIS software, equally as powerful as the well known commercial programme ArcGIS. It is possible to do things with QGIS that are not possible with Google Earth, including more complicated analysis and cartography.

It is very possible to learn to use GIS software such as this: a great tutorial to start is available here. An experienced user can analyse data and create maps quickly, but be aware that it can also be time consuming and is not always needed when the task can be just as well done with Google Earth.

Elevation Data

Satellite elevation data can be more reliable than data collected using a GPS and can be used (with care) for water network design. There are significant limitations, and if there is vegetation coverage it will not be so accurate.

Satellite elevation data is available for free online, typically with a resolution of 30 x 30 metre squares. This can be adequate for water network design in relatively flat areas, although it is still not ideal. The SRTM 30m data is probably of the best known (an easy downloader is here), although ALOS World 3D – 30m (AW3D30) is also extremely good.

It is also possible to purchase higher resolution elevation data. These can provide resolutions down to 0.5 metre x 0.5 metre squares. At this level of detail it should be very possible to design water networks in any areas without significant vegetation coverage. Typically AW3D or Airbus data might be used, but these need to be purchased from a broker. Several brokers are available, for example we have succesfully used L3Harris in the past. Prices start from around $5 USD per square kilometre.

In some responses, drones may be in use already, or it may be possible to commission a drone survey. These can provide extremely detailed elevation data.

The most accurate data will of course come from a topographic survey, although this is relatively more expensive.

Aerial imagery

Aerial imagery taken by satellites is freely available online. This includes the imagery within Google Earth, and image ’tiles’ which can be used in other applications from Google or Bing maps. Often in humanitarian situations having more up-to-date imagery is important, as well as having a higher resolution. Very high resolution, taken on known dates, can be purchased from various outlets. As with elevation data, we have previously purchased from L3Harris. The price varies depending on the recency of the image and the resolution, but can be available from around $20 USD per square kilometre.

Similarly with elevation data, drones can provide very high quality aerial imagery. Of course, this is not available everywhere. In some responses this imagery has been shared on OpenAerialMap (you can also look here to see examples of what is possible).