Don: Thank you again for your help (in my new neighborhood). I guess I somehow had the idea that data corresponding to a town *was* geo-referenced, since I also have the coordinates of that town's outline, and maybe that was where I was driving myself crazy.
I understand the idea of editing the dbf file to get the data I want in there, and that certainly helps me begin to clear the air. But let me ask something else, since my task is simple, but I expect to have to do it quite often. The towns that I have are divided. Some are non-contiguous and there are lots of islands (I'm on the shore). Some towns make up twenty or thirty entries. There are only a few dozen towns, but nonetheless, editing the spreadsheet is more of a pain than it sounds (39 towns, 311 entries). I know that doing a join is possible in the spreadsheet, but it is, shall we say, somewhat inelegant, and like I said, this is going to happen a lot. Is this the GIS-approved way to go, or is there something better I could learn about? Say I have another pile of shape data, like zip-code outlines or census tracts. If I want to map those outlines to my town shapes, and come up with a list of zip codes or tracts that overlap each town, what would I use? I don't mind being pointed at something with a shallow learning curve, so long as I know that it will, in fact, have what I need somewhere up the slope. My problem so far has only been that from as far down here as I am, I can't tell what's on which slope. Again, I thank everyone for their indulgence of such basic questions. Thanks, -tom Don MacQueen <[EMAIL PROTECTED]> wrote: > Hi, Tom, > > From what you've described as your immediate need (each town colored > according to the values of the data) you don't need GRASS. > > Assuming you've got the attribute data associated with the locations, > as described by Micha, then in Qgis, in the layer list on the left, > select the layer of interest, then right click (or control-click) and > select "Properties". This will bring up a place where you can control > the colors, or rather, select the method that Qgis uses to determine > the colors. You want "Unique Value" in the "Legend Type" drop-down > menu (in the Symbology tab of the Properties dialog box). > > That right-click thing also lets you open the Attribute Table, which > is a place where you can see the dbf data from within Qgis. > > -Don > > At 12:20 PM -0500 11/26/07, tom sgouros wrote: > >Micha Silver <[EMAIL PROTECTED]> wrote: > > > >> From what I read between the lines of your message, I gather that > >> you have data in a text file, and a separate shape file of towns, > >> with no connection between them. And you want to display the shape > >> file in a map with each town appearing differently, depending on > >> some data from the separate text file. Am I on the right track? > > > >Exactly the right track. Thank you for explaining how to get my data in > >place by editing the dbf file. > > > >> Well, QGIS does not yet have any way to "join" between a GIS layer > >> and a separate data file. All the data must be contained in the > >> shapefile's table of attributes. This table is stored in a "dbf" > > > >Does that mean that I should just think of QGIS as a graphics package, > >meant for displaying geo data that is processed and joined somewhere > >else? Sort of a way to file the layers in a project and display the > >ones I need? Is the PostGIS connection only for getting vector and > >raster data into QGIS, a slicker way than reading a file, or is there > >something more you get from that connection? > > > >If that's right, can you help me understand what I get by adding GRASS? > > > >Many thanks, > > > > -tom > > > > > >> file with the same name as the shapefile. (You might already know > >> this: each shapefile is composed of at least 3 disk files: i.e. > >> towns.shp, towns.shx and towns.dbf). You can open the shapefile's > >> dbf part in a spreadsheet program like OpenOffice calc (or MS > >> Excel), and then you can add additional columns (attributes) to the > >> dbf from you ascii data file. Next copy-paste the actual data from > >> the ascii file into the proper columns. > >> I *highly suggest* you save a backup copy of the original shapfile > >> dbf file just in case something goes wrong. That way you wan't loose > >> your whole shapefile. > >> > >> Now open the shapefile with the edited dbf in QGIS and you will be > >> able to use the data for displaying, labeling, etc... > >> > >> Cheers, > >> Micha > >> > >> > >> >-----Original Message----- > >> From: [EMAIL PROTECTED] > >> >[mailto:[EMAIL PROTECTED] On Behalf Of Tom Sgouros > >> >Sent: Monday, November 26, 2007 4:11 PM > >> >To: qgis-user@lists.qgis.org > >> >Subject: [Qgis-user] getting started for a complete GIS beginner > >> > > >> > > >> >Hello all: > >> > > >> >Can anyone point me to an example of how to get started with > >> >QGIS? I was pointed to QGIS by a number of people who > >> >suggested it was an easy way to get started in GIS. So I > >> >downloaded it, and it works, but I still can't figure out how > >> >to do what I need to get done. > >> > > >> >I have an ESRI shape file for some town boundaries, and I have > >> >some data for those towns. I used the shape file to draw a > >> >nice map of the towns. > >> >It's all blue, and I don't know why yet, but it looks nice, > >> >and that's fine. But for the life of me I can't find the > >> >correctly shaped slot through which to slip the data I want to > >> >display. What I have is an ASCII (ok, UTF-8) table of data, > >> >with different scalar values for each town, and what I want is > >> >a map, with each town colored according to the values of the > >> >data. What do I need to do to get this data onto my map? > > > >What do I call this data in order to make sense of the manual? > >> > Do I need to start a PostGIS server somewhere? I only have a > >> >few dozen towns here. > >> > > >> >(I'm on a Mac, OSX 10.4.9, trying to use QGIS version 0.9, and > >> >the GRASS menus don't appear. I think I understand how I > >> >should have run things to see them, but don't know if that is > >> >essential for what I'm trying to accomplish. The relationship > >> >between GRASS and QGIS remains a little mysterious to me, and > >> >if enlightening me on that point will help me understand my > >> >problem, please do.) > >> > > >> >Because I've been browsing the archives of this list, I have > >> >to suggest that there are a couple of forms of help that I > >> >don't need. One is pointers to the QGIS manual, which I've > >> >looked at, and I'm sure is a great book, once you already > >> >understand the important concepts. For me, I'm beginner > >> >enough that I don't know whether the data I want to chart is > >> >(or should be) a vector layer, raster layer, a PostGIS layer > >> >or something else (none of them sound right to me), so I find > >> >myself unable to make any sense of the help in the book. I > >> >also don't need a pointer to a block diagram or general > >> >overview about how GIS systems work. At this point, I feel I > >> >could draw them in my sleep, but arrows pointing from "data" > >> >icons to little "map" icons don't address the problem I'm > >> >having which is where is the place to start learning about > >> >using this particular GIS system on my data? > >> > > >> >Many thanks in advance for indulging my ignorance on all this, > >> > > >> > -Tom > >> > > >> > > >> >-- > >> > ------------------------ > >> > tomfool at as220 dot org > >> > http://sgouros.com > >> > http://whatcheer.net > >> >_______________________________________________ > >> >Qgis-user mailing list > >> >Qgis-user@lists.qgis.org > >> >http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user > >> > > >> > > >> > > >> >This mail was sent via Kinneret Mail-SeCure System. > >> > > >> > > >> > > >> > > > > > > > >-- > > ------------------------ > > tomfool at as220 dot org > > http://sgouros.com http://whatcheer.net > >_______________________________________________ > >Qgis-user mailing list > >Qgis-user@lists.qgis.org > >http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user > > > -- > -------------------------------------- > Don MacQueen > Environmental Protection Department > Lawrence Livermore National Laboratory > Livermore, CA, USA > 925-423-1062 > -------------------------------------- > -- ------------------------ tomfool at as220 dot org http://sgouros.com http://whatcheer.net _______________________________________________ Qgis-user mailing list Qgis-user@lists.qgis.org http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-user
