Tips for Collecting Accurate Geospatial Data for Restoration Areas (Geotagged Photos, Polygons, and GPS Points)

This guidance provides details that addresses frequently asked questions from restoration champions ranging from how to collect geospatial data for restoration areas (polygons and centre points) to how data quality is assured.

How Do I Collect Polygons and Centre Points?

There are 2 ways to collect polygons and centre points for your project:

1. Using Flority and greenhouse.
2. Using GPS devices. (This method needs approval from your Data Quality Analyst).

How Do I Collect Data Using Flority, Where to Best Take Photos, and How Many?

The following video will guide you on How to Collect Polygons on Flority 

When collecting data for your restoration area, the field enumerator, or our Geospatial Lead must follow these steps to ensure high-quality data:

1. Enable GPS and Location Services:
   • Ensure that your phone's GPS or location is enabled.
   • Select the data collection option in the Flority app.
   • Enable automatic data upload.
   • Ensure the training option in Flority remains unchecked.
   • Private mode should be activated if you want to keep your photos private - while still being able to share it on greenhouse.
2. Collecting Polygon Data:
   • Move around the corners of the plot/parcel/farm boundary, taking a picture at each corner on #polygon mode, ensure to close your polygon with the #polygon-end mode.
   • When taking a photo, ensure your phone’s camera faces inside the restoration area.
3. Centre-Points Data:
   • Using the option GPS CenterPoint, collect a geotagged photo per restoration area at the centre of the plot/parcel/farmland, in the direction where the trees have been planted.
4. Number of Photos required:
   • Polygons: There is no fixed number of geotagged photos required per polygon; it depends on its number of corners. You should, however, take one photo per corner/polygon vertex. For complex polygons, take a geotagged photo  at intervals of about 5 meters to capture the shape accurately while conserving phone storage.
   • Centre Points: You are required to take only one centre point photo per farm/planted area.

With the following video,you will learn How to Collect Centerpoints on Flority: 

What are Some Common Polygon Errors and How to Avoid Them?

Several errors can arise during data collection, including:

1. Spikes, Gaps, Overlaps, and Incomplete/Unclosed Polygons:
   • Plan the field trip well before the actual data collection date.
   • Map each polygon once by walking around the edges of the plot to avoid overlaps and gaps.
   • Change the point/photo tag to polygon-end when collecting the last point to close the polygon. This helps in eliminating spikes that can arise due to closing the polygon at the wrong location.
   • If one should have to pause recording due to unforeseen weather events or low battery it is possible to revisit the site within 48 hours and continue the polygon recording and finish it with #polgyon-end.
   • Should the surveyor forget to finish the polygon recording with a final photo with #polygon-end the system will autoclose the polygon which may add errors to polygon.
2. Missing or Incomplete Polygon Attribute Information:
   • Make sure you select #polygon-end to display attribute information.
   • Fill out attribute information accurately.
   • If you lack the required information, consult your geospatial lead or your project lead.
3. Self-Intersection:
   • Ensure careful mapping and data collection to avoid self-intersections. This can be done by collecting data along the edges of the polygon and not inside the polygon. 
     Note: You should collect a geotagged photo inside the restoration area only when picking a centre point of the plot/polygon.

Find more guidance on how to identify and fix common errors on greenhouse. 

As a Field Enumerators, How Should I Estimate the Size of The Planted Area/Farm When collecting Center Points?

Estimating the size of a polygon can be challenging. However, you can follow these tips:

1. Check the Unit Area when entering attributes:
   • Verify the unit area (hectares, square meters, or acres) and choose the one you are comfortable with.
2. Consult the Farmer:
   • Ask the farmer how big their farm is, this may however be rough estimate.
   • Check the land title deeds for accurate measurements, if applicable
3. Consulting the Agriculture Extension Agents/Officers (If applicable):
   • Ask the Agriculture Extension Agents operating in the farmers’ zone to furnish you with the estimated size (ha, Sq. Meters, and Acres) of farmlands if it is unknown to the farmer.

What is the quality assurance process for geospatial data?  

Quality assurance is a collaborative effort between the field enumerators, geospatial lead, and data quality analyst.

By watching this video, you will get instructions on how to create geofences on greenhouse

This can be also achieved through the following guidelines:

1. Pre-data Collection Planning:
   • The geospatial lead must inform the data quality analyst and plan the data collection schedule two weeks before the actual date. 
   • This also entails training all field enumerators who will be participating in the activity, providing the required equipment like android gadgets, internet, GPS devices and credentials for projects using flority.
   • Allocation of specific sites/restoration areas/blocks to one or a few field enumerators. This can help to avoid some errors in collected data like overlaps/duplicates.
2. Daily Updates:
   • On each day of data collection, the geospatial lead must update the data quality analyst to monitor incoming data and work together to address errors promptly.
3. The Quality Assurance Process:
   • The geospatial lead and data quality analyst review and resolve errors on the greenhouse. platform.
   • Once data is reviewed, geospatial leads create geofences (boundaries) around data for each site and associate this to exact site names on TerraMatch.
   • Data quality analyst pushes data to respective sites on TerraMatch and informs geospatial lead. The push is only done by the data quality analyst.
   • Non flority projects upload data directly to respective sites on Terramatch.
   • Once data is on TerraMatch, the data quality analyst performs a quality check and informs the geospatial lead of any identified errors.
   • The geospatial lead review the polygons, resolve the errors and re-submits new polygons. The data quality analyst then runs final checks and approves polygons. 
   • All members of your project who have access to TerraMatch will be able to see the polygons/centre points, associated errors/comments/approval statuses.
   • Error-free polygons will be approved by the data quality analyst, and this will be communicated back to the geospatial lead.

Learn how to upload polygons to terramatch for non-Flority user projects

Our team is available for any further assistance, please contact [e-mail] or contact your data quality analyst or project manager.