| GCP REQUEST CHECKLIST |
|---|
| 1. A drone that supports AGL (MSL is not currently supported.) |
| 2. Do you have the correct EPSG code? |
| 3. Do you have at least 4 GCPs measured with high precision GPS? |
| 4. Are all your GCPs clearly marked, unobstructed, and visible in at least 4 images? |
| 5. Are your GCPs at least 50ft from the edges of your map? |
| 6. Do your CSV column headings and units match your EPSG code? |
| 7. Does your CSV follow the prescribed template for checkpoints and non-checkpoints GCPs? |
If you have met these requirements you are ready to add GCPs to your map.
Please read the following step by step guides for a full walkthrough on the GCP process with DroneDeploy:
If you are unsure if you meet a specific requirement, we have gone into more detail about each point below.
You can also find more information about these requirements in our 6-minute GCP overview video.
1. Do you have the correct EPSG code?
To successfully process a GCP map you must have the exact EPSG code that was used to measure your GCPs. If the EPSG code you submit is different than the one used to record your GCPs we will be unable to process your map.
Need a refresher on Projections, Reference Systems, or EPSG codes? Check out this guide on the many intricacies related to global accuracy to help better understand and improve upon your map's accuracy.
2. Do you have at least 4 GCPs measured with high precision? GPS?
DroneDeploy requires a minimum of 4 GCPs for processing. In our experience, 5 GCP work great, and very rarely are more than 10 needed, even for particularly larger maps. Please note that if you decide to use more than 10 GCPs processing time for your map will increase.
Please review our guide that explains the best practices for Capturing GCPs.
3. Are your GCPs clearly marked and unobstructed?
A quality GCP can be as simple as two intersecting lines. The goal is to create a visible feature on the area that is being flown. Because flying altitudes are generally from 250-400 ft (about 75 to 120 meters), the GCP needs to be clearly visible in as many images as possible. Each GCP must be visible in at least 4 images or we cannot include it.
4. Are your GCPs at least 50ft from the edges of your map?
We highly recommend leaving a 50ft buffer between your GCP and the boundaries of your map. This is because if your GCP falls outside the map boundaries, even by 1 foot, we cannot process it. What a waste! Our recommended GCP placement strategy is to use 4 GCPs located in the 4 corners of your map on relatively flat surfaces with one more in the center.
Again, DroneDeploy requires a minimum of 4 GCPs for processing. In our experience, 5 GCP work great, and very rarely are more than 10 needed, even for particularly larger maps.
5. Do your .CSV headings and units match your EPSG code?
If your GCPs were measured using WGS84 (EPSG: 4326) then your column headers must read: GCP Label, Latitude, Longitude, Elevation (m). WGS84 uses Lat/Long in decimal degrees and the metric system for the Elevation.
If your GCPs were measured using a State Plane coordinate system, for example, NAD83 / California zone 3 (EPSG: 2227). then your column headers must read: GCP Label, Northing, Easting, Elevation (ft). In this case, measurements in NAD83 use Northing/Easting and Elevation in and US survey feet.
Still unsure about the ESPG code units? Please follow the steps on our GCP .CSV File Formatting guide.
6. Does your .CSV follow the prescribed template for checkpoints and non-checkpoints GCPs?
Please make sure you do not alter the template in any way and make sure your file is saved using a .csv file extension.
If you are using checkpoints, please ensure that the name of your GCP target contains the word checkpoint. Please visit the GCP .CSV File Formatting to correctly format your CSV file before processing your map.
If you follow the instruction listed in this section you should be good to go. Happy precision mapping!