Re: Help on transform a map to GIS

Hi,

answers in the text below

I need to express it as elevation on a 2D. I don't need a 3D
representation. I could mark the elevation by colors or by elevation
contour lines. the problem is if a software can understand an
elevation count line made by a pencil or if I need to perform this
exercise directly inside a software.
which is it the best way to perform this task?

Hum, there are different answers based on the complexity of your map and of the cash you have... basically, you have 2 options:
1) scan and georeference your map, then try to do a raster to vector conversion. It might be more complicated than one think, especially if you have lots of other items on your map! Then, assign an elevation attribute to each vector contour line and voila. You can use tools such as Topo to Raster, in ArcGIS (there may be an open source alternative), to derive an elevation surface. You now know the elevation of any point in your map.
2) scan and georeference your map, then digitize, by hand, each contour line. It is easy as you just have to follow the scanned line! ... good luck if your map covers a large extent!

Once your image is georeferenced, you can either vectorize it (a lake becomes a polygon etc), or work with is as an image. Then, you can easily add information to your map. You want to add a road? create a georeferenced polygon of the road and put it on top of your image! In any GIS software, the overlay will be made in function of the coordinates of each items, so you are guaranteed to have things located at the right place...
Jean

Do you have some idea of which software I can use in any steps?
And in which softare I can store the data as final product?

There are several softwares to do that... commercial would include ArcGIS and MapInfo. There are free alternatives, such as GVSIG, Grass, Qgis, uDig etc (google "open source gis")

For saving your data, again, there are lots of possibilities. You can save your data in a geo-database or in individual files. You can save your data as vector data (contour lines) or as a raster, an image (elevation surface). In the first case, the SHAPEFILE format (ArcGIS) is the most standard one... but you are free to use other ones, like GXML (XML doc providing the coordinates of every point in the dataset, basically). For rasters, you can do what you want... you can save your image as a jpg if you want to! (and have an header file along, providing information on the location and projection used). Common formats are also GeoTIFF (header in the file), Erdas Imagine (.img), ENVI (plain binary files, header in a separate file)... so the real question to ask is what do you want to do with this file? ... if your game already has its "geographical engine", send you can find / create a format that perfectly suits your needs!

Jean


Thank you!
MEtilico



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