Terraservice data not aligning

[Sean Gillies]

On Jan 3, 2005, at 9:00 AM, Camden Daily wrote:

> Hello all.  I've got a layer in my map file that I'm grabbing from
> terraservice, and it's mostly working great.  However, when I overlay
> some Tiger/Line street data over the terraserver image, things aren't
> quite lining up.  It's very, very close, but just slightly offset when
> zoomed in (maybe by 20-50 feet).
>
> My map file, the terraservice layer, and the tiger/line data are all
> projected as EPSG:4326, so I don't think it's a projection issue.  Has
> anyone else experienced any issues mixing these two data sets?
>
> Is it possible to 'tweak' a layer so that it's offset by a short
> distance?  I know about the 'offset' parameters for styles, but those
> only take units of pixels (which will look good at some zoom levels,
> but not others...)  I'd be grateful for any suggestions.
>
> -Camden Daily
>
> terraserver layer:
>
>   LAYER
>     NAME "aerial"
>     TYPE RASTER
>     STATUS OFF
>     MINSCALE 1000 # trying to grab too small a scale might result in
> an error from terraservice
>     CONNECTIONTYPE WMS
>     CONNECTION
> "http://terraservice.net/ogcmap.ashx?
> VERSION=1.1.1&SERVICE=wms&LAYERS=urbanarea&FORMAT=image/jpeg&STYLES="
>     METADATA
>      "wms_srs" "EPSG:4326"
>     END
>     PROJECTION
>       "init=epsg:4326"
>     END
>   END
>
> tiger/line layer:
>
>   LAYER
>     NAME "aerial_road_small_near"
>     TYPE LINE
>     STATUS OFF
>     DATA "tgr17031lkA"
>     MAXSCALE 100000
>     CLASSITEM "CFCC2"
>     CLASS
>       EXPRESSION /A4|A5|A6|A7/
>       COLOR 150 150 150
>     END
>     PROJECTION
>       "init=epsg:4326"
>     END
>   END
>
>

Camden,

TIGER streets are not very accurate in some locations.  In my
neighborhood, Northern Colorado, the TIGER streets are very close to
reality in Fort Collins and Larimer County ... but pan over to Boulder
and there is a pervasive offset from reality.  No comment on the
mindset of either community intended :)

You could shift the streets to align them with the imagery, but you
would almost certainly be shifting them out of synch somewhere else.

Sean


--
Sean Gillies
sgillies at frii dot com
http://users.frii.com/sgillies