[Gdal-dev] OGR: VRT

Stephan Holl stephan.holl at intevation.de
Wed Nov 15 11:04:03 EST 2006


Dear List,

I am connecting to  a mysql-table using OGRs VRT-driver.

My ovt-file:
OGRVRTDataSource>
    <OGRVRTLayer name='values'> 
<SrcDataSource>MYSQL:usr_web1_1,user=web1,host=localhost,port=3306,tables=n2n_flmflaeche</SrcDataSource>
    <SrcSQL>select n2n_wert, n2n_idflm, n2n_wertdat, n2n_idflaeche, frmt_wert, 
replace(replace(replace(format(n2n_wert,3),'.',';'),',','.'),';',',') as 
format_wert from n2n_flmflaeche
        where n2n_idflm = 1207
        and n2n_wertdat between '2004-01-01' and '2004-12-31'
        order by n2n_wertdat</SrcSQL>
    </OGRVRTLayer>
</OGRVRTDataSource>


The Database-query using mysql commandline-tools results in in 1 row:
select n2n_wert, frmt_wert, 
replace(replace(replace(format(n2n_wert,3),'.',';'),',','.'),';',',') as 
format_wert from n2n_flmflaeche
 where n2n_idflm = 1207
 and n2n_wertdat between '2004-01-01' and '2004-12-31'
 order by n2n_wertdat;
+----------+-----------+-------------+
| n2n_wert | frmt_wert | format_wert |
+----------+-----------+-------------+
|   95.600 | 95,600    | 95,600      |
+----------+-----------+-------------+
1 row in set (0.01 sec)

The datatype of n2n_wert is decimal.

All good for now.

Using ogrinfo on my ovf-file it gives a strange rounding value
Layer name: values
Geometry: None
Feature Count: 1
Layer SRS WKT:
(unknown)
n2n_wert: Real (0.0)
n2n_idflm: Integer (0.0)
n2n_wertdat: String (0.0)
n2n_idflaeche: String (0.0)
frmt_wert: String (0.0)
format_wert: String (0.0)
OGRFeature(values):0
  n2n_wert (Real) = 95.59999999999999   <--- strange, should be 95.600
  n2n_idflm (Integer) = 1207
  n2n_wertdat (String) = 2004-12-31
  n2n_idflaeche (String) = 04000000
  frmt_wert (String) = 95,600
  format_wert (String) = 95,600

Is this a known problem?

I am on Debian with gdal-1.2.6

Best regards

	Stephan



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