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

learn more… | top users | synonyms (1)

21
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 ...
20
votes
5answers
5k views

How to determine if a tiff is georeferenced or not?

I received a tiff file from someone, but I'm not sure if it's georeferenced. Is there an easy way to check this?
14
votes
3answers
349 views

Which CRS would you use to georeference historical world maps?

Which CRS would you recommend to georeference historical world maps like the ones in the London Geographical Institute - The Peoples Atlas - 1920, e.g. The map displays a lat/lon grid which I would ...
14
votes
1answer
840 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 ...
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.
11
votes
3answers
5k views

Is it possible to georeference an existing, un-georeferenced pdf?

I was wondering if there was anyway to georeference a pdf directly without first converting it to an image. I have access to ArcGIS 10.1 but haven't been able to find any information that would ...
11
votes
1answer
249 views

Assign projection to a satellite image

Today I stumbled upon a picture taken from the ISS looking down Europe and it is really beautiful. So, I started thinking I could add more to the picture. Like world borders, cities, road network, ...
10
votes
4answers
4k views

What is the difference between geocoding and georeferencing?

After some googling around both seem to be interchangable words, where we speak of tying the spatial info of a real place and storing in database. But still I am not satisfied, there should be some ...
10
votes
1answer
482 views

What is some theory on the number of GCP when georeferencing?

Just wondering, is it always better to have more than 3 GCPs? Should the GCPs be spread out evenly? Where can I find some general resources on the theory of this? Other than trial an error, which ...
10
votes
2answers
649 views

How can I improve my Georeferencing results?

Background This is my second question related to georeferencing naked raster maps in order to re-visualize them on different coordinate systems and in conjunction with other data layers. The previous ...
9
votes
6answers
4k views

How to georeference a vector layer with control points?

I have a non-georeferenced vector layer that I need to be georeferenced. With raster layers the task is easy and straightforward, but I have no idea what should I do with my vector layer. I have a few ...
9
votes
3answers
445 views

How to outsource scanning and georeferencing maps?

We have some historical paper maps and we want to get them scanned and geo-referenced and ultimately make a seamless map for a particular time. What vendors supply this service? (I have found ...
9
votes
2answers
2k 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 ...
9
votes
2answers
232 views

Does a Scanned Map have to be georeferenced in the projection of the original Source?

I have a historic paper map for the Indian Sub-continent which has been scanned. The Map is in Albers Equal Area Conical projection, and has the latitude and longitude grid on it. I was trying to ...
8
votes
1answer
917 views

Is there an explanation of Root-Mean-Square-Error (RMSE) for Dummies available?

Having an all-round expertise in GIS is sometimes not enough to fully understand some concepts of GIS Science. To add to this, I am also not a mathematician. Considering this, would anyone be able ...
7
votes
3answers
227 views

Merge images first, or georeference first?

I'm wanting to georeference and vectorise some features from scans of the OS 1896 Town Plans that I have purchased from the NLS (http://maps.nls.uk/os/london-1890s/info.html). The scans provided are ...
7
votes
2answers
420 views

How to Georeference Photos With No Spatial Reference?

I have about 100-200 field ground shot photos I would like to overlay in ArcGIS 10 that have no spatial information which I need to somehow develop using a photogrammetric formula. The camera was ...
7
votes
2answers
121 views

How to keep track of changes to geo-referenced data and maps?

At my company we are starting to get more serious about keeping track of changes to our geo-referenced data and maps. I'm looking into this and am wondering how people do it at other companies. We ...
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?
6
votes
3answers
1k views

30,000 data points… can this be reasonably served using openlayers?

I'm trying to tackle a web GIS problem and need to figure out the best strategy. I have a map with 30,000 cells on it forming a grid for the province of Alberta. I have a list of data points for ...
6
votes
1answer
5k views

Georeferencing a shapefile with ArcGIS 10.1

I have a shapefile with some polygons that I would like to superimpose to a raster image, but unfortunately they don't match perfectly due to the reference system the shp has been created with. So, I ...
6
votes
3answers
12k views

Steps to creating a GeoTIFF

First off, I'd like to mention that I'm pretty new to working with GIS, so please forgive my inexperience. My situation is as follows: I'm tasked with georectifying a set of imagery and importing ...
6
votes
1answer
345 views

ISIS to GDAL to QGIS: Georeferencing Mars Images

I'm trying to use QGIS to view some images from the Mars Reconnaissance Orbiter Context Camera. I use ISIS3 to download the images and convert them to mapped .cub files, following the instructions ...
5
votes
3answers
6k 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 ...
5
votes
3answers
996 views

Help required to convert georeferenced (and rectified) TIFF orthophotos to georeferenced .JPG format

I am not a GIS specialist (so patience required!) :) We work with georeferenced, rectified 1:10 000 orthophotos. I need help with the conversion of a georeferenced tiff to a georeferenced jpg. Our ...
5
votes
3answers
3k views

How to generate world files for raster X?

Given a list of georeferenced rasters, about a hundred, what is the simplest method to generate world files for each? In this case the source rasters are either geotiff with embedded georeferencing ...
5
votes
5answers
869 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 ...
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
1answer
299 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 ...
5
votes
1answer
254 views

Georeferencing a jpeg in QGIS but the scale is way off

I've gone through the really helpful walk-through(s) of how to georeference a jpeg in order to make it a layer, but after inputting the coordinates (either by typing in actual coordinates or clicking ...
5
votes
1answer
235 views

How do I georeference a ski map?

I have a map of a mountainous landscape, http://skimap.org/data/989/60/1218033025.jpg. It contains a number of known points, the lat-longs of which can be easily found out using google maps. I wish ...
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 ...
5
votes
2answers
3k views

Which coordinate system and projection shall I use for georeferencing google map image in ArcGIS?

I have saved Google Maps image (not Google Earth) of area at latlon(17.692437,83.218689) by some method in jpeg format. It is an exact snapshot of the Google Maps. Now I need to geo-reference it to ...
5
votes
1answer
598 views

Calculating distance in WGS84 (MySQL and Geoserver)

Here is the environment in which I work: An application using geo-referenced data Database MySQL 5.5, storing georeferenced points A Geoserver server, connected to the MySQL database Here is the ...
5
votes
1answer
396 views

Determining Natural Origin for a GeoTIFF file (Lambert Conic)

I am trying to display an existing GeoTIFF file (from the FAA WAC set) in an application that requires the GeoTIFF NaturalOriginLongitude tag (FalconView 5.1.1). There are some older files in that set ...
4
votes
3answers
722 views

How do I specify a CRS for a fictional game map in QGIS?

I am about to start playing a steampunk RPG game called The Iron Realm, which uses a fictional world map. I have recently started using QGIS v1.7 and have no real experience with GIS sysstems. I have ...
4
votes
3answers
1k views

Convert an arbitrary meta-data-free map image into QGIS project

My background: experienced programmer, amateur historian, complete beginner to GIS (so I'm using QGIS). I did learn to use the QGIS georeferencer tool though. The input: suppose I have an image like ...
4
votes
2answers
595 views

QGIS affine - form of equation

I am at the mercy of a govt authority who have provided utility information in a cad format with a 0,0 origin and a nonsense grid. About a dozen files, the grid and origin are entirely arbitrary. To ...
4
votes
4answers
7k views

Trouble when georeferencing CAD files in ArcMap

I've definitely got at least a couple of grey hairs while trying to convert some dwg. files to shapefiles. I've seen that this subject has been disscused a lot, but hope someone will have the ...
4
votes
1answer
538 views

Extract coordinates for series of georeferenced files in ArcGIS 10?

I have a series of 1900 spatially continuous images that are georeferenced. Each image is a tif file paired with a tfw file. These images are easily open and shown in ArcMap 10. However, I need a way ...
4
votes
1answer
297 views

Historical U.S.G.S. Georeferencing

I have downloaded a historical USGS map that is suppose to be a geoPDF. My understanding is that QGIS cannot directly read geoPDF's. I have not had any luck in converting it to a geoTIF in order to ...
4
votes
1answer
80 views

Area calculation of an object without coordinates

I have a photo of an object with a scale and I want to calculate its area. I guess I have to create a polygon of the area to be calculated to use the 'field calculator'. But how do I tell the program ...
4
votes
2answers
1k views

Display Georeferenced Images on Android

I'm looking for an Android application (best would be Open Source), that can display georeferenced images on top of a map (Google, OSM, ...). By Georeferenced I mean that the images four corners are ...
4
votes
1answer
301 views

Direct Georeferencing with X,Y,Z and Omega, Phi, Kappa

I have images taken from plane, it's longitude, latitude, elevation, omega, phi, kappa. I suppose that earth is flat (I don't need any DEM on that stage) and I want to calculate how image is nailed to ...
4
votes
1answer
300 views

Problem converting georeferenced jpgs to geotiff - image is shifted/warped

I have hundreds of georeferenced jpgs in ArcGIS 10 that I need to convert to geotiffs. I'm trying to use GDAL translate to create geotiffs from them. Everything works great except that the ...
4
votes
0answers
480 views

How to digitize directional drilholes from scanned vertical sections?

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 ...
3
votes
5answers
1k views

How to find coordinates for a lot of locations based on the town or village name?

I have got an Excel spreadsheet with roundabout 15,000 locations, which are only identified by the towns or villages name and the country. I am intending to present these on a world map. Therefore, I ...
3
votes
3answers
1k views

Georeference to x y coordinates with one lat long origin?

We are running parallel transect lines for a survey, which will roughly cover a rectangular area. When making the transects, we will periodically capture spatial locations of features and events we ...
3
votes
2answers
1k views

Georeferenced 3D Model Import

How can we open a 3D MAX File(3D Building model with exterior and interior elements)in Autodesk Infrastructure/LandXplorer or ESRI CityEngine? How can we georeference a 3D vector building model?
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 ...