Hot answers tagged remote-sensing
As Chad Cooper mentioned, what you want to perform is called Object-Based Image Analysis (OBIA). It's a fairly complex process which segments and then classifies an image. There are many programs out there which will perform this for you. However, you will require high-resolution, multi-spectral imagery. Incorporating LiDAR will probably help you out ...
The reason why it looks pixelated at 1:2500 (and probably at 1:10K or 1:20K) is that you are looking at a single resolution cell (30 metres on the ground, as pointed out by Mapperz) across multiple pixels on the screen. Lets assume that you're looking at a 30m cell at 1:1000 (in true scale, ignore that your monitor probably doesn't really do that) - that ...
If you really want to use python, and you need functionality similar to GRASS, perhaps the easiest solution would be to use GRASS via Python. That isn't specific to Landsat8, but I don't think a processing solution should be tied that closely to a specific satellite. You could implement some simple wrappers / higher level functions if you're consistently ...
The best source of information on this now defunct satellite is through the European Space Agency (ESA). Here is an ESA link to the Envisat mission. Pay particular attention to the Key Resources section of the web page--here you will find all the technical specifications of the instruments.
The ground track repeat cycle for ASTER is 16 days, which means every 16 days the pattern of orbit is repeated. So, each year a ground track is repeated (365/16) approximately 23 times. Therefore, you can acquire images of the same area 23 times per year. The orbit period is approx. 98 minutes. Therefore, each year there are (365*25*60 = 547500/98), give or ...
One of the best OBIA programs available for feature extraction is called Feature Analyst by Overwatch. There is a good promo video on road and building extraction here. The software is available as an extension for ArcGIS and Erdas Imagine. Unfortunately, this is not opensource software.
You might consider using GRASS (which interfaces with QGIS) for this process. See this link for more information: http://grasswiki.osgeo.org/wiki/LANDSAT The answer provided by @markusN on this question provides additional information and examples of what GRASS can be used for with Landsat-8.
Only top voted, non community-wiki answers of a minimum length are eligible