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

[Rebecca Handcock]

Also double check that you have the right UTM zone specified. I have
imported USGS DEM quads before, and there are several UTM zones in
Washington State. Sometimes I forget and wonder why all of my Seattle data
is in Greenland.

Thanks
Rebecca

---------------------------------------------------------------------
Rebecca Handcock Ph.D.                             Research Associate
Dept. of Earth and Space Sciences
University of Washington                    RebeccaH at u.washington.edu
Seattle, WA 98195-1310        http://faculty.washington.edu/rebeccah/

On Fri, 21 Nov 2003, Phil Hurvitz wrote:

> You need to be absolutely certain what your original projection parameters
> of your points are before you do anything else.  NAD27 and WGS84 are only
> datums, and thus are only 1 of the many projection parameters you need to
> be certain of.
>
> -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 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
> > >>
> > >>_______________________________________________
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> > >>
> > >
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