GCP txt file format

So I am curious what is the exact format one should use for the text file of the GCP coordinate info. If anyone has an example file they would like to post that would be awesome. Also is there a relatively cheap GPS unit that anyone here would recommend for collecting GCP data?

Thanks!

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Have you checked here?
https://docs.opendronemap.org/gcp/

Here’s the CSV Import Format for GCP Editor Pro:

1. Your .CSV must contain 4 columns
2. The first row (header) must be: GCP Label,Y,X,Z
3. Each subsequent row contains the label and coordinates of your ground control points (in the selected coordinate system units specified by the EPSG code)
4. No cells can be left blank
5. GCP Labels must be unique

Here’s an example from GCP Editor Pro:

The first row must be a valid projection string (PROJ) or EPSG code
After the header your gcp_list.txt must contain at least 6 columns separated by spaces or tabs:
geo_x  geo_y   geo_z   im_x    im_y    image_name  [gcp_name]    [extra1]    [extra2]    ...
The first 3 colums are the geo coordinates in the selected coordinate system units: (latitude, longitude, elevation) or (northing, easting, elevation)
Elevation values can be set to "NaN" to indicate no value
The 4th and 5th columns contain the GCP pixel coordinates in the image
The 6th column contains the image file name
The 7th column (optional) contains the name of the GCP. If this information is not provided, the names of the GCPs will be autogenerated
Extra columns are allowed
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I didn’t know about (Ground Control Points — OpenDroneMap 2.7.0 documentation) that is super useful!

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Glad it helped!

I’ll be expanding everything over time, so please keep a bookmark for the top-level docs in the back of your head as a resource to check :slight_smile:

I use GCP Editor Pro to generate my GCP file. Contact me by private message and I will give you a write up that I have put together on how to do it and a copy of what my file looks like.

Gene

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check out ardusimple.com to build a cm RTK option for around ~$300, cannot vouch for how accurate they actually are though.

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GCP Editor Pro is a great product and worth becoming proficient with. You need to be prepared with the EPSG/Proj coordinate system of the area you’re working on. One detail I would point out is that you might typically start from a file of Survey Control Points (SCP), convert them into an acceptable GCP .csv file per the formatting required by GCP Ed Pro, and from that create the Ground Control Points (GCP) using the editor. The editor then allows you to create a mapping between the Survey Control Points (highly accurate) and the imagery (generally less accurate). Here’s an example of survey control points turned into an acceptable GCP .csv file for starters -

GCP Label, Northing, Easting, Elevation
tar100,1404657.37584,2302441.15434,1080.71328
tar101,1404640.44331,2302450.54315,1080.53198
tar102,1405051.03156,2303096.10118,1084.26678
tar103,1405034.51457,2303106.29322,1084.03328
tar105,1405111.55162,2303252.91253,1073.72088
tar106,1405172.98730,2303265.71142,1070.35978
tar107,1405134.45069,2303280.83168,1071.74018
tar108,1405422.06293,2303746.64291,1033.57908
tar109,1405407.09264,2303758.97447,1033.84268
tar110,1405791.95481,2304200.12394,1025.65638
tar111,1405775.35624,2304209.99096,1025.07768
tar113,1404198.66619,2303785.12584,1048.05128
tar114,1404844.63907,2303409.09787,1062.59318
tar115,1404852.04210,2303430.55979,1061.87938
tar116,1405507.84787,2303052.83910,1080.08398
tar117,1405518.17806,2303073.39255,1079.91688
tar119,1405942.87186,2302840.57959,1102.99978

Then here is the final gcp_list.txt file after mapping to imagery using the product -

EPSG:2885
2303052.8391 1405507.84787 1080.08398 2582.2921348314608 474.29855537720704 DJI_0774.JPG tar116
2303052.8391 1405507.84787 1080.08398 2503.379614767255 1185.7463884430176 DJI_0775.JPG tar116
2303052.8391 1405507.84787 1080.08398 2468.3836276083466 1879.6276083467094 DJI_0776.JPG tar116
2303073.39255 1405518.17806 1079.91688 2840.56050955414 514.0891719745223 DJI_0774.JPG tar117
2303073.39255 1405518.17806 1079.91688 2788.416401273885 1202.4458598726114 DJI_0775.JPG tar117
2303073.39255 1405518.17806 1079.91688 2727.558917197452 1925.656050955414 DJI_0776.JPG tar117
2302840.57959 1405942.87186 1102.99978 2758.0955056179773 298.63242375601925 DJI_0782.JPG tar119
2302840.57959 1405942.87186 1102.99978 2705.53290529695 939.8138041733547 DJI_0783.JPG tar119
2302840.57959 1405942.87186 1102.99978 2626.2086677367574 1613.3836276083466 DJI_0784.JPG tar119
2302441.15434 1404657.37584 1080.71328 1326.5537720706259 676.314606741573 DJI_0626.JPG tar100
2302441.15434 1404657.37584 1080.71328 1357.8451749734888 1386.8589607635206 DJI_0627.JPG tar100
2302441.15434 1404657.37584 1080.71328 1388.0369181380418 2081.6436597110755 DJI_0628.JPG tar100
2302450.54315 1404640.44331 1080.53198 1089.1300160513642 685.0979133226324 DJI_0626.JPG tar101
2302450.54315 1404640.44331 1080.53198 1115.6171749598716 1396.545746388443 DJI_0627.JPG tar101
2302450.54315 1404640.44331 1080.53198 1150.887640449438 2081.6436597110755 DJI_0628.JPG tar101
2303096.10118 1405051.03156 1084.26678 1194.8041733547352 641.1813804173355 DJI_0613.JPG tar102
2303096.10118 1405051.03156 1084.26678 1229.6629213483145 1332.3178170144463 DJI_0614.JPG tar102
2303096.10118 1405051.03156 1084.26678 1256.1500802568219 2061.3322632423756 DJI_0615.JPG tar102
2303106.29322 1405034.51457 1084.03328 949.7579617834394 653.5031847133758 DJI_0613.JPG tar103
2303106.29322 1405034.51457 1084.03328 967.3208598726114 1350.5732484076434 DJI_0614.JPG tar103
2303106.29322 1405034.51457 1084.03328 1002.3105095541401 2073.7834394904457 DJI_0615.JPG tar103
2303252.91253 1405111.55162 1073.72088 860.7640449438202 553.3483146067416 DJI_0610.JPG tar105
2303252.91253 1405111.55162 1073.72088 904.8178170144462 1247.2295345104333 DJI_0611.JPG tar105
2303252.91253 1405111.55162 1073.72088 940.0882825040128 2002.593900481541 DJI_0612.JPG tar105
2303265.71142 1405172.9873 1070.35978 1411.5668789808917 1054.3184713375797 DJI_0610.JPG tar106
2303265.71142 1405172.9873 1070.35978 1502.0826645264847 1721.5280898876404 DJI_0611.JPG tar106
2303265.71142 1405172.9873 1070.35978 1546.1364365971108 2494.4590690208665 DJI_0612.JPG tar106
2303280.83168 1405134.45069 1071.74018 3197.398073836276 518.215088282504 DJI_0648.JPG tar107
2303280.83168 1405134.45069 1071.74018 3135.6404494382023 1253.2680577849117 DJI_0649.JPG tar107
2303280.83168 1405134.45069 1071.74018 3074.2945425361154 1947.1492776886034 DJI_0650.JPG tar107
2303746.64291 1405422.06293 1033.57908 1123.583806715844 595.0005668541127 DJI_0600.JPG tar108
2303746.64291 1405422.06293 1033.57908 1150.750401284109 1212.0963081861958 DJI_0601.JPG tar108
2303746.64291 1405422.06293 1033.57908 1203.5874799357946 1853.2776886035313 DJI_0602.JPG tar108
2303746.64291 1405422.06293 1033.57908 1220.8796147672551 2509.2808988764045 DJI_0603.JPG tar108
2303746.64291 1405422.06293 1033.57908 1238.583467094703 3115.3290529695023 DJI_0604.JPG tar108
2303758.97447 1405407.09264 1033.84268 931.0304975922953 649.9646869983949 DJI_0600.JPG tar109
2303758.97447 1405407.09264 1033.84268 957.5176565008026 1256.0128410914926 DJI_0601.JPG tar109
2303758.97447 1405407.09264 1033.84268 992.7881219903692 1897.1942215088282 DJI_0602.JPG tar109
2303758.97447 1405407.09264 1033.84268 1018.8635634028892 2561.980738362761 DJI_0603.JPG tar109
2304200.12394 1405791.95481 1025.65638 1941.1107544141253 395.2487961476725 DJI_0590.JPG tar110
2304200.12394 1405791.95481 1025.65638 1967.5979133226324 1106.6966292134832 DJI_0591.JPG tar110
2304200.12394 1405791.95481 1025.65638 1994.0850722311395 1712.744783306581 DJI_0592.JPG tar110
2304200.12394 1405791.95481 1025.65638 2020.1605136436597 2324.8314606741574 DJI_0593.JPG tar110
2304200.12394 1405791.95481 1025.65638 2046.6476725521668 2913.3130016051364 DJI_0594.JPG tar110
2304209.99096 1405775.35624 1025.07768 1756.6613162118779 412.81540930979133 DJI_0590.JPG tar111
2304209.99096 1405775.35624 1025.07768 1765.5818619582665 1106.6966292134832 DJI_0591.JPG tar111
2304209.99096 1405775.35624 1025.07768 1792.0690208667736 1712.744783306581 DJI_0592.JPG tar111
2304209.99096 1405775.35624 1025.07768 1818.1444622792937 2316.0481540930978 DJI_0593.JPG tar111
2304209.99096 1405775.35624 1025.07768 1853.4149277688603 2922.096308186196 DJI_0594.JPG tar111
2304209.99096 1405775.35624 1025.07768 1871.1187800963082 3519.361155698234 DJI_0595.JPG tar111
2303785.12584 1404198.66619 1048.05128 773.0682182985554 87.8330658105939 DJI_0745.JPG tar113
2303785.12584 1404198.66619 1048.05128 896.1717495987159 729.0144462279294 DJI_0746.JPG tar113
2303785.12584 1404198.66619 1048.05128 1010.0802568218298 1376.2343499197432 DJI_0747.JPG tar113
2303785.12584 1404198.66619 1048.05128 1098.0505617977528 1955.9325842696628 DJI_0748.JPG tar113
2303785.12584 1404198.66619 1048.05128 1203.5874799357946 2430.23113964687 DJI_0749.JPG tar113
2303409.09787 1404844.63907 1062.59318 2582.2921348314608 456.7319422150883 DJI_0761.JPG tar114
2303409.09787 1404844.63907 1062.59318 2573.64606741573 1185.7463884430176 DJI_0762.JPG tar114
2303409.09787 1404844.63907 1062.59318 2582.5666131621188 1774.2279293739969 DJI_0763.JPG tar114
2303409.09787 1404844.63907 1062.59318 2564.725521669342 2544.414125200642 DJI_0764.JPG tar114
2303409.09787 1404844.63907 1062.59318 2556.0794542536114 3194.378812199037 DJI_0765.JPG tar114
2303430.55979 1404852.0421 1061.87938 2793.091492776886 456.7319422150883 DJI_0761.JPG tar115
2303430.55979 1404852.0421 1061.87938 2810.7953451043336 1185.7463884430176 DJI_0762.JPG tar115
2303430.55979 1404852.0421 1061.87938 2810.932584269663 1800.577849117175 DJI_0763.JPG tar115
2303430.55979 1404852.0421 1061.87938 2784.3081861958267 2535.6308186195824 DJI_0764.JPG tar115
2303430.55979 1404852.0421 1061.87938 2784.4454253611557 3194.378812199037 DJI_0765.JPG tar115

Note that multiple images are mapped to individual target points. There is a minimum requirement of 3 images per control point. Below is the target control points shown in the geographic region -

image

And here is one of the survey control points being selected in image # 0603. Note the zoom and target positioning.

image

Once completed for all points, you can generate a file like the one I pasted in above by saving your changes and generating the gcp_list.txt file. Have fun!

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Also sorry if I am posting to many questions, I am still a beginner with webODM and I am really trying to develop an in depth understanding of the software.

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Questions are Good™️, and you’re reading around the forum and the docs, so what else can I ask of someone?

Besides, if you still have questions, that means I have to clear stuff up or expand stuff, so that’s welcome feedback!

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