3
votes
2answers
49 views

What is the closest CRS to “Meridiano de Greenwich”

I have a 1906 scanned map that I am trying to georeference in QGIS for Mac. The map has French and English lat-long, indicating them as either "Meridiano de Greenwich" or "Meridiano de Paris." I would ...
1
vote
1answer
47 views

Why do features in QGIS drawn on same datum as Google imagery from OpenLayers move? [duplicate]

I have just started using QGIS. I've loaded the "openlayers" plugin and added a google hybrid layer, which is based off the WGS84 datum to my understanding. Now I create a shapefile and add a new line ...
1
vote
1answer
44 views

Georeferencer plugin will not load in QGIS

I have downloaded and installed QGIS. I would like to georeference an image using the core georeference plugin. When loading it no toolbar appears and the 'update', 'reinstall' etc boxes in plugin ...
0
votes
0answers
17 views

Transformation type - when to use which type? [duplicate]

I am using QGIS 2.0.1 on a Mac, and I am georeferencing a scanned map from 1822. The image is an excellent quality scan, and includes a grid of lat-long. I do not know much else about the map that ...
1
vote
2answers
86 views

QGIS:what does it do “snap gcp coordinates to background layers” in the Georeferencer plugin?

Maybe is too obvious, but I don't find any precise documentation about this checkbox in the georeferencer plugin.
3
votes
3answers
108 views

How to match air photo to existing vector layers on Mac OS?

I'm trying to add an air photo to a project and match it to existing data. CanVec data is mostly based on the old CIA dataset of the 60's and is hopelessly out of date, but the roads are up to date - ...
1
vote
1answer
222 views

How to Georeference a tiff with correct coordinate system

I am having difficulty in georeferencing an existing tiff (already has georeference information - but is out of alignment). Using the georeference plug-in I can create the map's GCP in the 4 corners ...
2
votes
0answers
119 views

Install Georeferencer Plug-in QGis 1.7.0 OS X

I'm trying to install the Georeferencer plug-in in QGis 1.7.0 on Mac OS X (10.5.8). However the plug-in doesn't show up in the list. I have used "enable 3rd parties directory" and I have checked ...
2
votes
2answers
369 views

How to create a “Datum-less” projection in QGIS?

I want to use QGIS to do some georeferencing and image registration. On ArcMap10 I can define an "Unknown Projection", basically a default metric grid, and use it as a grid for georeferncing. In QGIS ...