Looking for open/free viewing software for DEM/geotiff

[andrekje]

Some end users does not have tools to view/do measurement on geotiff/DEM
can you please suggest open/free software that can view, and preferably do some basic measurements on data processed by Photoscan Pro (in any suitable format)?   - preferably multiplatform.

I am aware of the Agisoft viewer, it does great job viewing 3D .tls models but what if user needs to see it as orthophoto/meassure ?

[Dave Martin]

Have you looked at the LizardTech "GeoViewer" - basic viewer free with linear measurements, "Pro" version apparently can measure areas etc. for USD 50    http://www.lizardtech.com/products/geoviewer/

(no connection but I do use the free viewer for GeoTiff quickview)

Dave

[Mdaemon]

i would suggest to use Quantum Gis. Its freeware.

Martin

[andrekje]

Thanks, Thile I am aware of Qgis, the problem is that  it is ridiculously slow to browse geotiff.  tiled or not, full redraw on every pan/zoom operation, and while my workstation load a given tile size in x seconds, qgis spends a lot more time to do the same job.

[JRM]

A tiled geotiff means faster browsing when you zoom in or pan the view.

If you want a fast display when zooming in/out, you will have to build overviews/pyramids which are copies with reduced resolution and will be displayed instead of the source when it better suits the scale view. If you don't have them, QGIS will have to fetch all the tiles in the view at their native resolution.

For QGIS, look at the layer properties to build, you can change the default interpolation algorithm.

To sum it up : pyramids + tiles makes a 60Gb tiff fast.