[Qgis-us-user] Need Help

QGIS QGIS US
1

I have a shapefile of firestations and a shapefile of roads, I need to do an analysis and find the 5 mile “DRIVING DISTANCE”, not as the crow flies, point on the roads from each firestation. Are there any suggestions? Any help would be greatly appreciated.

Edwin L. Hawkins Jr., GISP

Henderson County E911

GIS Administrator

Phone 731.968.5911

Cell 731.358.7932

Direct Line 731.651.2062

2

Ed,
Some initial thoughts; literally back of the envelope

  • Constrain the problem by first realizing that all ‘drive-able’ 5-mile distances will occur.
  • So, determine all road intersections within a 5-mile radius centered on a firestation
  • Then use a program like ‘pgRouting’ (http://pgrouting.org/) to generate a list of the shortest distance from the firestation to each road intersection within your radius.
  • Then order list of shortest distances.
  • Label those intersections that are less than 5 miles (shortest distance from pgRouting) from your fire station with a green dot or symbol.
  • All other intersections label with a red dot or symbol.
    This is a rough, first draft and I would think it would give you a reasonable idea (at least to the nearest intersection from the station) of your 5-mile driving distance.

Regards,
Dave

···

On Fri, Feb 28, 2014 at 11:55 AM, Ed Hawkins <ehawkins@henco911.com> wrote:

I have a shapefile of firestations and a shapefile of roads, I need to do an analysis and find the 5 mile “DRIVING DISTANCE”, not as the crow flies, point on the roads from each firestation. Are there any suggestions? Any help would be greatly appreciated.

Edwin L. Hawkins Jr., GISP

Henderson County E911

GIS Administrator

Phone 731.968.5911

Cell 731.358.7932

Direct Line 731.651.2062

Qgis-us-user mailing list
Qgis-us-user@lists.osgeo.org
http://lists.osgeo.org/cgi-bin/mailman/listinfo/qgis-us-user

3

Ed,
Typo; First few lines should read as follows:
Ed,
Some initial thoughts; literally back of the envelope

  • Constrain the problem by first realizing that all ‘drive-able’ 5-mile distances will occur within a 5-mile radius region, centered on the firestation.

  • So, determine all road intersections within a 5-mile radius centered on a firestation
    …

Dave

···

On Fri, Feb 28, 2014 at 11:55 AM, Ed Hawkins <ehawkins@henco911.com> wrote:

I have a shapefile of firestations and a shapefile of roads, I need to do an analysis and find the 5 mile “DRIVING DISTANCE”, not as the crow flies, point on the roads from each firestation. Are there any suggestions? Any help would be greatly appreciated.

Edwin L. Hawkins Jr., GISP

Henderson County E911

GIS Administrator

Phone 731.968.5911

Cell 731.358.7932

Direct Line 731.651.2062

Qgis-us-user mailing list
Qgis-us-user@lists.osgeo.org
http://lists.osgeo.org/cgi-bin/mailman/listinfo/qgis-us-user