# [postgis-users] Calculate the distance

Obe, Regina DND\MIS robe.dnd at cityofboston.gov
Mon Aug 7 05:54:42 PDT 2006

```Haven't tried these myself with PostGIS, but I think these might be good
libraries to try if you are doing pure .NET development.

http://sharpmap.iter.dk/ (this I have tried with shape but not yet with
postgis in VB.NET ASP.NET 2.0 environment.)

http://www.monogis.org/ (haven't tried this one at all, but looks
promising.

UMN mapserver also has a .NET interface via SWIG, but its been a while
since I've tried it and I got some threading issues with it when I did
and I think its most suitable for web development and not for desktop
development.  I could be wrong since I don't do much desktop and haven't
attempted to use in desktop.
http://ms.gis.umn.edu/

the examples are in C#, but its a fairly trivial exercise to convert
snippets of them to Vb.NET format using one of the online c# to vb
converters
e.g.
http://www.kamalpatel.net/ConvertCSharp2VB.aspx

Regina

________________________________

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
gates jr
Sent: Saturday, August 05, 2006 7:48 PM
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] Calculate the distance

I'm Gates, a university student. I got two problems:

1.
I have a table called "state_point table". I calculate the
distance between a new point to all point in my table with query:

CREATE TABLE distance AS
SELECT distance(state_point.the_geom, geomfromtext('POINT(100000
200000)',-1)) AS distance, state_id, state_name
FROM state_point
order by distance

My Question is : what measure unit that's return by this query? Meters?
Miles? Or another? If it's not in meters how could I convert it to
meters?

2.
I want to make user interface in VB.NET 2005, which driver or
connection should I use to show my map? Is there any VB.net or another
language samples, which use postgreSQL/postgis database, that I can
access in the internet? (a link site? ) I'm a kind of people that learn
by example.

Thank

Gates

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