Îles Kerguelen - FSX Projects

Geography

The Kerguelen Islands (in French commonly Îles Kerguelen, officially Archipel des Kerguelen), also known as Desolation Island, is a group of islands in the southern Indian Ocean. It is a territory of France.
The Kerguelen Islands are located at 49°15′S 69°35′E. The main island, Grande Terre, is 6,675 km² and it is surrounded by another 300 smaller islands and islets, forming an archipelago of 7,215 km². The climate is raw and chilly but not severely cold throughout the year - much like that of the outer Aleutian Islands of Alaska - with frequent high winds, and while the surrounding seas are generally rough, they remain ice-free year-round. (Source: Wikipedia)

Motivation

I have decided on creating this project because the original DEM used in default FSX scenery has too low resolution and do not reply the reality anywise. First I have tried to download some finished projects, but all I have found was broken. Because I can't use DEM, where isn't most of the mountains, I have downoloaded SRTM3 DEM from NASA FTP server and made bgl scenery. It have turned out that there is an unacceptable inaccuracy between default FSX vector data and this DEM (shifts around 300 m southwise), I have been forced to make my own vector data.

I have planned that works on this project takes only one whole day, but I have entwined unseemly. I have worked ten days and this project is still full of defects. I haven't know anything about FS sceneries and making bgl and I have made a lot of geographic/cartographic lapses. I don't have time to making it once again, so this data isn't usable for mapmaking. Everyone who can make it again and properly is cordially welcome.

About data

The whole hypsography is derived from NASA SRTM3 version 2 data with resolution of ca 60 m in meridian and 90 m in parallel direction. The biggest problem of this data is radar shadow areas. In these areas isn't known information about height and it makes deep holes. Unfortunately I don't know relatively easy mechanism how to repair these data. I tried FSTerrain 2002 but it don't work for me. It should be possible to make hypsography from another sources, for example from topographic maps. Meanwhile there is no edits of these data.

Water areas is derieved from French National Geographic Institute's topographic map of Kerguelen in scale 1:200,000. This map has been classified, water extracted, georeferenced on NASA SRTM3 version 2 DEMs. A contour line, representing sea shore, has been vectorized abreast of 0.5 m. Resultant line has been smoothed, but too much. All islands with area smaller than 5000 sq. m was cleared out. This is geographically wrong, too. But I haven't had time to representative selection of thousands of islands.

Fig. 1 - FSX Project Kerguelen ocean polygons

Ocean is divided into 15 polygons (as shown on fig. 1). As a island it should be defined by the hole in water polygon. But I haven't been able to make it correctly trough resample.exe, so I has had to use SBuilderX. But when I has tried to make hole, or change the water polygon to the "outer" (change the polygon border direction), it hasn't worked or it has worked wrong. So I has had to split this one polygon to more. Every island have to lie at least one border of two polygons.

There are very high number of wrong located lakes. The IGN map had been georeferenced through ca 20 binding points and 3rd polynomial transformation. The shore is referenced very well, but in the inland is the location error up to 200 m. I haven't been able to use lower level of polynoms with credit. All lakes with area smaller than 10,000 sq. m was cleared out. This is geographically wrong, great areas with high number of small lakes changed theirs character, but I really haven't time to control and correct them. The elevation for lakes are set by their centroids height, extracted from SRTM3 DEMs. Centroids aren't ideal points for elevation representation, so in some events I has had to correct it manually.

The water flows has taked most of time. I has resigned to classify it from IGN topomap because all accessible digital sources have too low resolution. Finally I have had to vectorize it by hand on the strength of SRTM3 DEM. Occasionally water flows uphill or not utterly at bottom of valleys. Bad work, too.

Roads at Kerguelen are in small count. I haven't made my own, so the default routes shifted ca 300 m southward should display.

Fig. 2 - Difference between default and this scenery

Known errors

Entire southwest sector is not displaying. I don't know where's problem, all processed data are correct. Every help welcomed.
Deep holes in surface. This is original feature of SRTM3 data. I don't know now how to easy mask it. Every help welcomed, too.
Water flows aren't displayed over lake and ocean beaches. This can be solved with water flow lines buffer which frets into ocean beach lines.
Lakes in central Grande Terre are bad localized. This is result of wrong georeferencing, used scanned map had too many distortions. It isn't useful to make it again, I'm bargaining for an satellite image classification into the future.
Too much smoothed shorelines. It should be made again and better.
Lot of small lakes and islets aren't displayed. For actual level of generalization (1:200,000) would it make lots of small simple triangles. I don't have time for representative selection and edits.
Rivers aren't in reference to DEM precisely localised. I has vectorized it in the scale of 1:25,000, but it looks that it isn't enough.

Data sources

NASA SRTM3 Version 2 Digital Elevation Model, in the concrete files S49E068.hgt, S49E069.hgt, S50E068.hgt, S50E069.hgt and S50E070.hgt. (Heh, I can't find address now...)
French National Geographic Institute's (IGN) topographic map of Îles Kerguelen from year 1973 in scale of 1:200,000.

Used software

3DEM v20.4, AFCAD v. 2.21 for FS2004, ArcGIS 9.2, GIMP 2.4.5, MSPaint 5.2, Notepad 5.2, OpenJUMP v1.2 D, resample.exe (FSX), SBuilderX v3.10 and FSX SP1 for testing.

Legal disclaimer

Everyone can use, distribute and edit this data at no cost but nobody can use and/or offer it for any money (incl. "service" charges like "packaging"). There must be my name and this webpage address stated at all times. The source of this data is governmental institution in both cases so please respect also their terms. (This disclaimer is informative, the disclaimer in Czech section applies.)

Files

Name	Size (kB)	Characterization	Download
cvx_Kerg_IGN68_SRTM3.BGL	822	Complete vector scenery in *.bgl format (excl. DEM).
Readme_Kerg_IGN68_SRTM3.txt	8	Read me file, download if you don't know how to install bgl file.
Kerg_SRTM_IGN68_1.zip	2652	All lines of Kerguelen project, as they was exported from SBuilderX in ESRI shapefile (zipped).
Kerg_SRTM_IGN68_2.zip	1487	All polygons of Kerguelen project, as they was exported from SBuilderX in ESRI shapefile (zipped).
Kerg_DEMs.zip	1507	Five SRTM3 DEM sections in bgl format (zipped)
Kerg_SRTM_IGN68.SBP	12,232	All vector data in SBuilderX project (no DEM).
Kerg_IGN68_SRTM3_complete.zip	2101	Complete Kerguelen scenery in 6 bgl files (zipped)