Re: [sf-bike-planner:0] Digest for sf-bike-planner@googlegroups.com - 1 Message in 1 Topic

[Garlynn Woodsong]

Amar-

Quick stab at answering your questions:

Questions for all the GIS experts out there:
 
1. qGIS offers a choice of many formats importing data via "Add Layer." I
noticed one of these is "CSV." Does anybody know details of the csv format
in gQIS? Would I be able to export my bike graph to CSV and view it in GIS
that way? I'm imagining csv with rows of [Lat,Lon,Value1,Value2,...] for
nodes and [StartLat,StartLon,EndLat,EndLon,Distance,Value1,Value2,...] for
edges.

Yes, you could export a series of x,y values to CSV, and then re-import them using the qGIS equivalent of "Add X,Y Values" by loading them as a CSV file. It should work just fine, as long as there is at the very least a column for Unique ID (maybe called OID and numbered sequentially from either 0 or 1), a column for X, and a column for Y... but the heading structure that you mention should, in theory, work as well -- I'm not entirely familiar with the qGIS data loading mechanism, however, so maybe somebody else can speak to that.

 

2. Another format qGIS supports is '.sql' file -- I think this is sqllite.
What would such a file look like and where would it come from? If I have a
programmed sql file generated using "pgsql2shp" could I read that in
directly some way? I'm guessing not, have to run it in a PostGIS DB and then
connect to the DB. Does anybody do this regularly now?

I've always thought of SQL as a query language, not a geographical data format, so... beats me! 

3. What is GRASS. Do I need it?

No. Not if you already have qGIS. It's the oldest open-source GIS program, and qGIS has a better interface with much the same functionality, as I understand it...

 

thanks
 
Amar


 

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