[UW-GIS-L] lat long points not visible on map

[Sacha Vignieri]

Hi Phil,
Thanks for getting back to me, and sorry to bother you again, but I am 
still having trouble. I've reprojected the points into the projection of 
the map (NAD27) and the map into the projection of the points (WSG84). I 
also tried reprojecting both into other projections. In both cases with 
no luck. I also tried adding the points in ArcView 3.2, in that case I 
couldn't even zoom to them as a theme.

It seems that it should be so simple...

Any other ideas? I am the lone GIS user in my department and so am 
pretty isolated.

Thanks so much for the help!
Sacha

Phil Hurvitz wrote:

> Sacha, you probably have defined your prj incorrectly.  Make sure your prj
> for your points matches the actual data.  If you know the projection
> parameters for your points, I suggest projecting the data set to a new
> data set stored in the same projection as the other data you want to use.
> 
> In addition, sometimes ArcMap attempts to be too smart for its own good,
> by reading the GeoTIFF headers embedded in images; even when you change
> the .prj for e GeoTIFF, the embedded parameters override the prj or tfw.
> 
> I also suggest viewing your data in ArcView 3.x, which lacks the ability
> to read GeoTIFF headers, and can't project vector and raster data
> simultaneously on the fly, and can't read .prj files for display purposes.
> 
> -P.
> 
> ******************************************************************************
> Phil Hurvitz, MFR | GIS Specialist | College of Forest Resources | 355 Bloedel
> Box 352100 | University of Washington, Seattle, Washington  98195-2100, USA
>  tel: 206.685.8179 | FAX: 206.685.3091 | e-mail: phurvitz at u.washington.edu
>              WWW: http://gis.washington.edu/phurvitz
> ******************************************************************************
> 
> On Fri, 21 Nov 2003, Sacha Vignieri wrote:
> 
> 
>>Hi,
>>I am a relatively new user of ArcGIS, although I did take a course in
>>ArcView a few years ago. I am having a problem getting lat long points
>>to appear on my map. The map is a mosaic of several USGS DEM quad maps
>>that has been texturized with DRG data that I purchased online at
>>MapMart, it is in a NAD 27 projection. The points are sample locations
>>in Lat Long that I collected with a GPS unit. I have been working in
>>ArcMap, and am able to successfully add the table and describe the
>>projection used (by selecting the .prj file I was given with the maps).
>>When I add the points however, they do not appear on the map. They are
>>listed first in the table of contents, so they are not hidden. Also,
>>when I select zoom to event I am able to see some of them (not all), but
>>not in the same area as the map. I know that the lat longs are correct,
>>and should overlap with the map.
>>
>>Any insight would be GREATLY appreciated, I have been struggling for days.
>>
>>Thanks for your time!
>>Sacha Vignieri
>>Department of Biology
>>University of Washington
>>Seattle,WA
>>sachav at u.washington.edu
>>
>>_______________________________________________
>>Uw-gis-l mailing list
>>Uw-gis-l at u.washington.edu
>>http://mailman.u.washington.edu/mailman/listinfo/uw-gis-l
>>
> 
> _______________________________________________
> Uw-gis-l mailing list
> Uw-gis-l at u.washington.edu
> http://mailman.u.washington.edu/mailman/listinfo/uw-gis-l