Howto:Create custom terrain: Difference between revisions

Jump to navigation Jump to search

Howto:Create custom terrain (view source)

Revision as of 17:14, 17 November 2009

2,197 bytes removed ,  17 November 2009
no edit summary
m (+ resource link, sorry John)
No edit summary
Line 39: Line 39:
* If you are running Windows, download QGIS from [http://www.qgis.org/en/download/binaries.html here] (Windows - Standalone).
* If you are running Windows, download QGIS from [http://www.qgis.org/en/download/binaries.html here] (Windows - Standalone).


The following is largely adapted from the [http://stattosoftware.com/flightgear/tutorial/index.html original QGIS scenery tutorial], which you may find of use.
# Launch QGIS.
# Launch QGIS.
# Click on <tt>Layer > Add a Raster layer</tt>.
# Click on <tt>Layer > Add a Raster layer</tt>.
Line 66: Line 68:


====Distinguishing Land Class Types from LANDSAT data====
====Distinguishing Land Class Types from LANDSAT data====
For people who have not worked with satellite imagery before, it may be difficult to figure out what certain areas of land are. Of course you need Google Maps or similair software running, to see what is what on the black/white image, but most areas can be recognised without. Here is a list which may help you:
You may Google Maps or Yahoo Maps running alongside your program to see what is what on the black/white image, but most areas are recognizable without use of the software. If you need help determining what part of the black-and-white image, please currently refer to the [http://stattosoftware.com/flightgear/tutorial/index.html#distinguishing original QGIS scenery tutorial].  
* '''Water''' is always black or very close to being black. However, shadows from clouds can also appear black on your image. If your image has clouds, use caution!
* '''Forests''' are also dark grey.
* '''Scrub Cover''' is like a forest, but lighter in color since the forest consists of shrubs, not trees.  
* '''Crops''' can be a wide variety of different colors, but are easily distinguishable by their field-like patterns. You have your choice between dry crops, mixed crops and irrigated crops - take a look at the corresponding texture to figure out which crop style best suits your area.
* '''Golf Courses''' should be digitized as a class even though we do not have a texture for them yet. They should be conspicuous by their pattern and their bright pixels.
* '''Urban Areas''' should have some semblance of a pattern to them. Pixels can vary from darkness to lightness.
* '''Towns''' are much smaller than urban areas and you may not be able to pick up any distinct patterns.
* '''Industrial Areas''' should be digitized if you know where the areas are. They are usually characterized by large, boxy buildings on the outskirts of urban areas, though this obviously varies by city!
 
===Digitizing tips and tricks===
* You can change the color of the shapefile by clicking on it in the left display toolbar. It usually is a good idea to set the transparency of the layer you are digitizing to between 50 and 75 percent so you can still see what you have digitized underneath the polygon. This can help you fix errors as they are introduced.
* If you have a large feature to digitize, such as a forest, you don't have to digitize all of it at one time! Instead, you can create small polygons labeled as 'forest' next to each other. Merging them into one polygon is pretty straight forward:
*# Go into edit mode and pick the Select feature (<tt>View > Select Features</tt>).
*# Click on the first polygon and then on the other(s), while holding the Ctrl-key. The selected polygons should turn yellow.
*# Click the Merge selected features icon (or <tt>Edit > Merge selected features</tt>).
*# Check whether the classes correspondend (if not, you might be mixing two different areas!) and click OK.
* If there is a lake (or other area) in the middle of a forest you have already digitized, you can use the QGIS ring feature to cut a hole in the polygon. You can then fill in the hole by creating another polygon.  


===Eporting the shapefile===
===Exporting the shapefile===
In order to turn the landclass into scenery we have to split it into seperate shapefiles for each landclass.  
In order to turn the landclass into scenery we have to split it into seperate shapefiles for each landclass.  


Statto
64

edits

Retrieved from "https://wiki.flightgear.org/Special:MobileDiff/17734"

Navigation menu