Howto:Create custom terrain: Difference between revisions

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Custom terrain in FlightGear is currently generated through processing shapefiles with [[TerraGear]]. In order to add custom scenery to FlightGear, you must create a custom shapefile.
'''Custom terrain''' in [[FlightGear]] is currently generated through processing shapefiles with [[TerraGear]]. In order to add custom scenery to FlightGear, you must create a custom shapefile.


A "shapefile" is a proprietary spatial information format. You can edit them with almost every GIS package. QGIS is quite a good package for this type of project.
A shapefile is a proprietary spatial information format. You can edit them with almost every GIS package. QGIS is quite a good package for this type of project.


Your goal for editing area data is to create a shapefile of a seamless layer of polygons which correspond to some type of land cover. This data is then fed into the mapserver and, possibly, TerraGear to create new scenery.
Your goal for editing area data is to create a shapefile of a seamless layer of polygons which correspond to some type of land cover. This data is then fed into [http://mapserver.flightgear.org the mapserver] and, possibly, TerraGear to create new scenery.


=== Evaluating the current data ===
=== Evaluating the current data ===
Before you begin, please make sure the area you want to improve doesn't already have good coverage. Just because it looks bad in FlightGear does not mean the area has not been improved. For this, you will need to check the Flightgear Mapserver, at [http://mapserver.flightgear.org/ mapserver.flightgear.org].
Before you begin, please make sure the area you want to improve doesn't already have good coverage. Just because it looks bad in FlightGear does not mean the area has not been improved. For this, you will need to check the Flightgear Mapserver, at [http://mapserver.flightgear.org/ mapserver.flightgear.org].


Let's take a look at the Finistère in Brittany, Western France: if you click [http://mapserver.flightgear.org/map/?lon=-4.41840585539649&lat=48.4484146908477&zoom=11&layers=0B000000FTTFFFFFTFT here], you will quickly see and understand how the Finistère county is known of [[FlightGear]]. Some towns/cities (red), a few forests (green), etc. Overall, it is not a very good resolution: a lot of angles, the detail level is not that good, some towns are missing. If you want a better definition on ground, there is some work to be done! The goal being to obtain something like this:
Let's take a look at the Finistère in Brittany, Western France: if you click [http://mapserver.flightgear.org/map/?lon=-4.41840585539649&lat=48.4484146908477&zoom=11&layers=0B000000FTTFFFFFTFT here], you will quickly see and understand how the Finistère county is known of FlightGear. Some towns/cities (red), a few forests (green), etc. Overall, it is not a very good resolution: a lot of angles, the detail level is not that good, some towns are missing. If you want a better definition on ground, there is some work to be done! The goal being to obtain something like this:


# [http://mapserver.flightgear.org/map/?lon=13.40385&lat=52.50199&zoom=11&layers=000000BFFFFFFFFFTFFF Berlin]
# [http://mapserver.flightgear.org/map/?lon=13.40385&lat=52.50199&zoom=11&layers=000000BFFFFFFFFFTFFF Berlin]
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[[File:C31e36f2a2cbb278a1603dfe2ba91193.media.395x288.png|thumb|200px|Landsat Map Search]]
[[File:C31e36f2a2cbb278a1603dfe2ba91193.media.395x288.png|thumb|200px|Landsat Map Search]]
[[File:1c9334d970963364b5ce1bc3a166a4fa.media.426x192.png|thumb|200px|Preview and download Landsat image]]
[[File:1c9334d970963364b5ce1bc3a166a4fa.media.426x192.png|thumb|200px|Preview and download Landsat image]]
Browse to [http://glcfapp.umiacs.umd.edu:8080/esdi/index.jsp the Earth Science Data Interface interface] ([http://glcfapp.glcf.umd.edu:8080/esdi/index.jsp mirror]) to grab your [http://en.wikipedia.org/wiki/Landsat Landsat] data.
Browse to [http://glcfapp.glcf.umd.edu:8080/esdi/index.jsp the Earth Science Data Interface interface] to grab your [http://en.wikipedia.org/wiki/Landsat Landsat] data.


# Click ''Map Search''.
# Click ''Map Search''.
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It is imporant to enable "snaping" now. We don't want small holes in our scenery, nor do we want overlapping polygons. Snapping adjusts each point as you go by - you will miss occasionally and have to correct it - so you don't have to worry about lining the polygons up precisely.
It is imporant to enable "snaping" now. We don't want small holes in our scenery, nor do we want overlapping polygons. Snapping adjusts each point as you go by - you will miss occasionally and have to correct it - so you don't have to worry about lining the polygons up precisely.


# Open <tt>Settings > Project Properties</tt> and click the Snapping options... button.
# Open <tt>Settings > Snapping Options</tt>.
# Click the tickbox(es) in front of your layer(s) and set Tolerance to 20 (map units). A smaller tolerance will make it easier to work with very small and detailed layers.
# Click the tickbox(es) in front of your layer(s) and set Tolerance to 20 (map units). A smaller tolerance will make it easier to work with very small and detailed layers, while a bigger value makes it easier to snap when zoomed out.
# Click OK to save the snapping options.
# Click OK to save the snapping options.


==== Distinguishing Land Class Types from LANDSAT data ====I
==== Distinguishing Land Class Types from LANDSAT data ====
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 Stattosoftware Scenery Tutorial]. Instead of determining in a single band image you can also combine different ETM+ bands in a RGB file. Some information about different band combinations can be found here [http://web.pdx.edu/~emch/ip1/bandcombinations.html].
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 Stattosoftware Scenery Tutorial]. Instead of determining in a single band image you can also combine different ETM+ bands in a RGB file. Some information about different band combinations can be found here [http://web.pdx.edu/~emch/ip1/bandcombinations.html].


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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.  


# Open the Attribute table (<tt>Layer > Open Attribute table</tt>).
# Open the Attribute table (<tt>Layer > Open Attribute Table</tt>).
# Type "Sand" (or another class) into the search box and press the Search button. This will select all polygons that have the Sand class assigned.
# Type "Sand" (or another class) into the search box and press the Search button. This will select all polygons that have the Sand class assigned.
# Go to <tt>Layer > Save Selection as Shapefile</tt> and save the sand shapefile somewhere on your computer.
# Go to <tt>Layer > Save Selection as vector file</tt> and save the sand shapefile somewhere on your computer.
# Do the same for all other classes.
# Do the same for all other classes.
# To make the difference between land and sea (landmass) we save the entiry shapefile (<tt>Layer > Save as Shapefile</tt>).
# To make the difference between land and sea (landmass) we save the entiry shapefile (<tt>Layer > Save as...</tt>, ESRI Shapefile).


If you want to see these shapefiles integrated into the Custom Scenery database you can contact papillon81 and statto (through IRC or Forum). Please be remembered that your data has to be derived from freely available (public domain) sources. Other material can not be integrated due to legal issues.
If you want to see these shapefiles integrated into the Custom Scenery database you can contact papillon81 and statto (through IRC or Forum). Please be remembered that your data has to be derived from freely available (public domain) sources. Other material can not be integrated due to legal issues.

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