distinctive points or markings (on the ground), whose positions (coordinates) are known and which are visible on photos or images -- used to help correctly position the photography or imagery for mapping or GIS

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Snap Ground Control Points (GCP) after georeferencing?

Does anybody know if it is possible to snap GCP:S after a georeferencing has been made? The coordinates are saved in a *.points file when using the georeferencer in QGIS and I am looking for a ...
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23 views

Change project CRS = discard GCPs?

[Using QGIS 2.12 Lyon on Mac with OS X 10.10.5] I am struggling to georeference some old hydrographic survey maps that are in the form of TIFF files (.tif). If I open the georeferencer tool and set ...
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28 views

Can targets placed on the facades of a building be used to increase the accuracy of a point cloud of a building generated from Drone/UAV/UAS imagery?

Can targets (used for registering point clouds) mounted on a building be used to increase the accuracy of a point cloud generated from UAV imagery?
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73 views

Why do collinear ground control points create larger residuals?

When georeferencing a raster image of a long corridor, why do collinear ground control points cause larger residuals? Say I am using the georeference function in ArcMap, and I have 6 ground control ...
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78 views

erdas LPS : Load Z values from a DEM?

I'm working on a photogrametric project with erdas LPS version 2013. I succeed in taking several ground control points (x and y values). However, i can't extract and load Z values from my raster DEM ...
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77 views

Finding angle to north on image with three control points

So I am working on some software that geolocates spots on a map taken from a drone. I am having some trouble with the actual geolocation when the map that the program is given is not aligned north. ...
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135 views

UAVs and using ground control

I have been having a conversation at the office about whether to use ground control when using drones/UAVs to capture aerial images. The ground control that I am referring too is any permanent survey ...
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61 views

Satellite image vertically squeezed after being georeferenced

I am using ArcGIS for Desktop 10.1. I am trying to georeference a Google Earth image in Christchurch area, New Zealand. I am using some CGPs I have got from this image (their Google Earth coordinates),...
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569 views

How to do geometric correction of remote sensing data in R?

My challenge is to replace most of the remote sensing commercial tools with R code (I'm teaching assistant at the University and I would like to move to open source R code to show the added values to ...
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257 views

AGI STK Server alternative

AGI has a server product called STK Server that exposes REST services to perform satellite acquisition planning. However the cost is astronomical $200k+ (pun inteded). They also have STK components (...
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Using PROJ.4 library to transform from local coordinate system coordinates to global coordinate system using ground control points?

I have a point cloud whose coordinates are with respect to a local coordinate system. I also have ground control points with GPS values. Can I convert these local coordinates to a global coordinate ...