[Shapelib] Using .shp files
Mateusz Loskot
mateusz at loskot.net
Mon Jun 12 11:18:08 PDT 2006
Corazao, Tony wrote:
> I am completely new to mapping and .shp files. All I’ve seen on line
> is usage of the .shp files and their conversion to/from other
> formats.
Hi,
Just for some introduction:
Shapefile (triple of xxx.shp, xxx.dbf and xxx.shx files) are one of
many formats to store data about features, as vector format.
Feature, is a "thing" that can be located in the space (2D or 3D),
is represented as a geometry and has assigned attributes.
Simply, e.g. a feature of a city can be represented as a single point (X
and Y coordiantes), the geometry, with assigned attributes like name,
number of citizens, etc.
Geometry is stored inside the .shp file of the Shapefile triple.
Attributes are stored in form of DBF table (.dbf file).
> Does anyone know where to get information as to how to use already
> creating .shp files in my programs? I have tested some of the .shp
> files on ArcMap and they’re just what I need, but I don’t know how to
> use them.
Hmm, it's really hard to answer to your question "how to use shapefile".
It depends on your objectives. So, you have to know what kind of
information you want to retrieve from shapefiles, what is your
application, etc.
In example, one can want only to display geometry of shapefiles on a map
and print it or just watch it for navigation purpose etc.
Another user's aim can be to get some "discrete" information and make
some analysis e.g. to learn what are the biggest cities (in are) in some
country, where is that nearest river from the city X, what is a spatial
distribution of plant of species X in Canada, etc.
So, without knowing more about your objectives, it's almost impossible
to give you any advice about how to use your shapefiles.
If you don't mind, if you're new for mapping and GIS, I'd like to
recommend you two amazing books that will:
- give strong foundation of mapping and GIS
- show how to operate with various vector and raster data formats
- how to prepare, process, convert data between formats
- how to do basic analysis
So, here are the books:
1) Web Mapping Illustrated - Using Open Source GIS Toolkits
By Tyler Mitchell
http://www.oreilly.com/catalog/webmapping/
Do not be confused about the "web" word in the title.
This book is an excelent introduction to GIS and mapping using Open
Source tools. Just read the table of contents and you will see it :)
2) Mapping Hacks
by Schuyler Erle, Rich Gibson and Jo Walsh
http://mappinghacks.com/
This is a kind of coockbook with a huge number of mapping recipes in
variousGIS and mapping subjects.
Cheers
--
Mateusz Loskot
http://mateusz.loskot.net
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