Ask MetaFilter questions tagged with shapefile

Maps of pipe networks

a womble is an active kind of sloth — Tue, 01 Dec 2009 08:19:21 -0800

Pipe-filter: Where can I find maps of pipe networks in US cities? I'm doing some research on exploring patterns that result from the physical infrastructure of US cities. I'm curious if anyone knows of any sources of data that show where water and waste-water pipes are located (preferably in shapefile format).The specific city does not matter.

I have explored ESRI's free data; Googling, geodata.gov, and other random sites which have not resulted in any information. I realize this is not common information, but thought it was worth asking the venerable hive-mind for suggestions.

dbf + dbf = 1992

tmcw — Tue, 28 Apr 2009 21:53:00 -0800

I'm working on some code for quickly pulling together shapefile data and other data (statistics, etc) and spitting out maps. That means JOINs. Thanks to the 1990-quality standards of GIS, attribute tables are in dbf files. How does one deal with these blasts from the past? I'd ideally like something like sqlite which can use dbf as a backend or quickly import and export dbf files. The line of thought of using xBase, xHarbour, xcetera seems to lead to this bizarro world of programming-language-database-solutions which makes 0 sense in the modern world.

What's a guy to do?

Also - I know, ideally, a spatial database is the way to go, but in this situation, I want people to be able to do this quickly, and I know that they'll have shapefiles and tables in csv, etc., not database-ed data.

Thanks for any guidance! I've hit my google limit and am now thinking there's something obvious I'm missing...

Join some of the dots, throw the rest away

genghis — Tue, 26 Jun 2007 08:46:19 -0800

Map geeks: can I generate a polygon shapefile from the outline of a large collection of points? There's more detail, of course. I'm all Googled out, so this is my next stop. Here's a slightly-genericised version of my need:

I am able to generate, from a dataset which is quite old, several thousand points. All of them are in the same area (say, a ZIP code).

In order to test whether new data points - which are newer than that ageing dataset - are inside the same area, I'd like to take what I have and create a shapefile.

This shapefile would need to be a polygon which tracks the outermost points from the cluster I have very tightly, in order to avoid false positives when testing new points. So a bounding box/circle/parallelogram won't do.

Can this be done? And more importantly, can it be done with an existing software package or component which has an open license?