Pulling numbers from ASCII filename not working

[IamIan]

I searched the archives but couldn't find anyone else with this
problem. Basically I'm grabbing all ASCII files in a directory and
doing geoprocessing on them. I need to calculate a z-factor based on
the latitude of the ASCII file being worked on, which is in the
filename. If I type in the code manually it works and reads the
latitude value from the ASCII filename, but when run within ArcGIS it
crashes when it gets to int(LatString). Isnumber() returned false for
Latitude as well. Is there something different about reading values
from an ASCII filename?

import sys, os, win32com.client , string, gc

# Get a list of ASCII files in the workspace for ASCII To Raster
conversion
filenames = os.listdir(gp.w orkspace)
filenames = [filename.lower( )
for filename in filenames
if (filename[-4:].lower() == ".asc" and filename[0] != "-" )]
for filename in filenames:

# For each ASCII file, create Hillshade.
# account for latitude by computing Z units using radians
Latitude = filename[1:3]
LatString = str(Latitude)
LatInt = int(LatString)
radians = LatInt * 0.0174532925
zFactor = 1/(113200 * (cos(radians)))

[Dave Hansen]

On Thu, 26 Jan 2006 06:39:20 GMT in comp.lang.pytho n, Dennis Lee
Bieber <wl*****@ix.net com.com> wrote:

On 25 Jan 2006 12:42:20 -0800, "IamIan" <ia****@gmail.c om> declaimed the
following in comp.lang.pytho n:

[...]

I tried print repr(filename) and it returned the actual filename:
'n16w099.asc' , 'n17w062.asc' , etc.

You may have problems with the longitude... those leading zeroes may
be taken as Octal notation...

Shouldn't be a problem unless you make it one. Int defaults to
decimal, unless you specify a base or tell it to infer the base from
the number format by specifying a base of zero.

a = int("062")
a 62 a = int("062",0)
a 50

Hard to interpret "099" as an octal number in any case:
a = int("099",0)
Traceback (most recent call last):
File "<pyshell#5 9>", line 1, in -toplevel-
a = int("099",0)
ValueError: invalid literal for int(): 099

Regards,
-=Dave

--
Change is inevitable, progress is not.

[Bengt Richter]

On 25 Jan 2006 12:42:20 -0800, "IamIan" <ia****@gmail.c om> wrote:

Thank you for the replies, I'm new to Python and appreciate your
patience. I'm using Python 2.1.

To reiterate, the ASCII files in the workspace are being read correctly
and their latitude values (coming from the filenames) are successfully
being converted to string. Even doing LatInt = int(LatString) works,
however the second I try to print LatInt's value or use it in
mathematical operations, the code chokes in ArcGIS.

My full code:

# Import system modules
import sys, os, win32com.client

# Create the geoprocessor object
gp = win32com.client .Dispatch("esri Geoprocessing.G pDispatch.1")
print gp.usage("Hills hade_sa")
print gp.usage("Raste rToOtherFormat_ conversion")
print gp.usage("Defin eProjection_man agement")

# Check license availability
gp.AddMessag e ("ArcInfo license is " + str(gp.CheckPro duct("ArcInfo") ))
gp.SetProduct( "ArcInfo")
gp.CheckOutExt ension("Spatial ")

# Set workspace
workspace = "E:\\GISTes t"
gp.workspace = workspace
gp.AddMessage( "Workspace = " + gp.workspace)

filenames = os.listdir(gp.w orkspace)
filenames = [filename.lower( )
for filename in filenames
if (filename[-4:].lower() == ".asc" and filename[0] != "-" )]
for filename in filenames:

# For each ASCII file, create Hillshade.
# account for latitude by computing Z units using radians
Latitude = filename[1:3]
LatString = str(Latitude)
LatInt = int(LatString) ^^^^^^--here you set LatInt to an integer
gp.AddMessage(" LatInt is " + LatInt)
radians = LatInt * 0.0174532925
zFactor = 1/(113200 * (cos(radians)))

The complete traceback:

Traceback (most recent call last):
File "e:\python21\py thonwin\pywin\f ramework\script utils.py", line
310, in RunScript
exec codeObject in __main__.__dict __
File "E:\Documen ts and
Settings\Admin istrator\Deskto p\Ian\GIS\Pytho n\zOnly.py", line 32, in ?
gp.AddMessage(" LatInt is " + LatInt) string--^^^^^^^^^^^^ ^^^^^^--integer
(LatString in place of LatInt might work, since it's a string (so is Latitude))TypeError: cannot add type "int" to string ^^^^^^^^^^ ^^^ ^^^^^^
This is not lying ;-)

I tried print repr(filename) and it returned the actual filename:
'n16w099.asc ' , 'n17w062.asc' , etc.

So you can see Latitude would be '16' '17' etc. right?

On to the next traceback ;-)

Regards,
Bengt Richter

[IamIan]

Thanks for the help everyone (especially those that gave more answers
than attitude). It's working perfectly!

Ian