fastest way to convert lon-lat to points

[Pagurek,Debbie [NCR]]

Hi Puneet,
How are you?

I am working on some similar work with .csv files and OGR right now.
I don't know why your field is being changed like that...

As for debugging, aside from the ogrinfo test, you might want to embed
your <OGRVRTDataSource> into a mapfile and then try the shp2img tool. If
this produces an image for you, all the mapserver stuff is fine. But you
might be having permissions problems on your server, which is where MY
problem lies right now. I'm using IIS5, not apache... So I have some
work ahead of me!

You might also want to write a little PHP script to make sure that your
ODBC DSN (a system DSN, right?) is working ok as well. It's when I did
this that I realized that my problem has nothing to do with mapserver,
ogrinfo etc.

Good luck and let us know what you discover,
Debbie Pagurek

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of P Kishor
Sent: Thursday, July 20, 2006 8:19 AM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: [UMN_MAPSERVER-USERS] fastest way to convert lon-lat to points

Folks,

I have seen this question asked in the past, and have a similar problem.
I want to convert many lon-lat to a shapefile of points quickly. The
lon-lat are in a csv text file (values.txt) like so

foo,bar,baz,long,lat,qux
1, bar1, baz1, -87.796341, 41.907504, s10 ...
...

So, I installed FW_Tools 1.05, created a DSN out of the text file (this
is and has to be on a Windows box), and ogrinfo happily gave me
information that I wanted, but with a twist...

OGRFeature(values.txt):1056
  foo (Integer) = 1
  bar(String) = ba1
  baz(String) = baz1
  long (Real) = -87.796341
  lat (Real) = 41.907504
  qux(String) = 10.0000

So, what's with interpreting qux? It converted my "s10" into a string of
value "10.0000".

Anyway, then I created an OVF file (values.ovf) like so

<OGRVRTDataSource>
  <OGRVRTLayer  name="values">
  <SrcDataSource>ODBC:values</SrcDataSource>
  <SrcLayer>values.txt</SrcLayer>
  <GeometryField encoding="PointFromColumns" x="Long" y="Lat"/>
  <GeometryType>wkbPoint</GeometryType>
  </OGRVRTLayer>
</OGRVRTDataSource>

well,

ogr2ogr -f "ESRI Shapefile" . values.ovf values

but while that seemed to do something without any error, I got no
output.

So, is what I am doing the right way of going about this? Is there a
better or another way to try out and benchmark? Oh, did I mention? --
The values.txt file has about 5.25 million rows, so speed is important.


--
Puneet Kishor http://punkish.eidesis.org/ Nelson Inst. for Env. Studies,
UW-Madison http://www.ies.wisc.edu/ Open Source Geospatial Foundation
https://edu.osgeo.org/