Tagged Questions

Aligning geographic data to a known coordinate system so it can be viewed, queried, and analyzed with other geographic data.

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3
votes
1answer
2k views

Georeferencing with Quantum GIS and reprojecting to EPSG:900913

I'm trying to reproject a map to EPSG:900913 The image I'm reprojecting is the following http://i.imgur.com/HmfLW.png I'm using the cities as reference points obtaining the coordinates from Google ...
5
votes
4answers
1k views

How to generate a world file with rotation

I`m writing code to geo reference some images that I get with a rc plane. I have the central coordinate of the image because its atached to the center of the plane. But I have problems when I open the ...
5
votes
5answers
995 views

georeferencing aerial photos with only known centroid

I have heaps of aerial photos that need to be georeferenced. I have access to ArcMap and ERDAS. All I am given is an excel sheet with the centroid coordinates of each image. Each photo covers an ...
1
vote
3answers
6k views

How to georeference a scanned map in ArcMap 9.3?

I want to georeference a scanned map of Sudan (Africa) as .jpg file format,coordinate points are marked on scanned map in 4 degree intervals. I am not familiar to georeferencing in ArcMap. So looking ...
5
votes
1answer
316 views

Unknown Coordinate System on old drawing

I work with many old civil engineering documents, and occasionally I'll need to georeference one which has coordinates pairs listed at many given points but does not list which coordinate system these ...
7
votes
3answers
7k views

Generally accepted root mean square (RMS) error for rectifying topographic maps

This is a generic inquiry on the common practice/standard for determining the acceptable values of RMS when georeferencing topographic maps. Is there an absolute value? Some literature suggests that ...
3
votes
2answers
916 views

Change output file type in QGIS georeferencer?

I have successfully georeferenced a raster file via the Georeferencer plugin (Georeferencer GDAL Version 3.1.9) in QGIS 1.7.0. However, I noticed that the output georeferenced raster file is in TIFF ...
5
votes
2answers
4k views

Convert x, y position in georeferenced image (with world file) to longitude, latitude?

What steps do I need to do in order to calculate longitude and latitude for a specific pixel in a georeferenced image? For example this image ...
2
votes
4answers
3k views

GIS newbie, How to georeference a jpeg metro map using OSS?

I have a metro map in jpeg format and I want to georeference it. My goal is to find GPS location of the metro stops and visualize them on google maps. Probably, the first step is to overlay the map ...
4
votes
0answers
496 views

How to digitize directional drilholes from scanned vertical sections? [duplicate]

I need an advice how to do this. Normally, I either receive a file containing drill holes or at least data with xy position, direction, depths and attributes. I then use this data for further ...
13
votes
7answers
2k views

Best method to georeference oblique photographs?

I have a series of oblique photos taken from an airplane of oyster beds that need to be mapped. Does anyone have any tips on georeferencing oblique images? I have access to ArcGIS and ENVI.
7
votes
1answer
1k views

automated georeferencing

I am attempting to fully automate the process of georeferencing a load of .png files - i have xml file containing the co-ordinates - but how can i use them? Does anyone have any advice?
2
votes
1answer
665 views

Georeferencing help (GeoTiff into MapWindow6)

I'm a newbie with MapWindow6 and I would like to figure out a couple of things. 1 - Whenever I drag and drop a GeoTiff into the map (MapWindow6) I can not see that image at its place, I mean that ...
14
votes
1answer
976 views

Are there any general rules of thumb for selecting a transformation for Georeferencing?

There are several transformations that can be used when georeferencing a raster: 1st order Polynomial (affine) 2nd order Polynomial 3rd order Polynomial Spline... etc Are there any specific rules ...
9
votes
2answers
3k views

How can I transform a georeferenced JPG to a georeferenced TIF?

I have an georeferenced JPG file and a JGW file containing the coordinates. How can I transform it to a georeferenced TIF file and a TFW file? I have tried to save the JPG file as an TIF file in ...
0
votes
1answer
675 views

How can I open a georeferenced JPG file in OCAD?

I have a georeferenced .jpg file with the .jgw file containing the coordinates. I want to use it as a background in OCAD. But when I open the file as a background, the jpg file is not georeferenced to ...
3
votes
2answers
1k views

Is it possible to use more than two control point links when georeferencing CAD files in ArcMap?

I'm trying to georeference CAD to a building footprint in ArcMap 10 (although I've had this same problem in earlier versions). The problem is, it won't let me use more than two control point links, so ...
24
votes
7answers
2k views

Work flow for georeferencing imagery using open source tools?

Does anyone have a recommendation for a work flow for georeferencing high resolution aerial photography using open source tools? Comparison of user friendliness and robustness between Quantum GIS ...