[Manifold-l] Exporting to shapefile: Displacement

Tue May 8 09:57:10 CDT 2007

Thanks Bob :

I'll check the scale issue.  It most likely seems a scale issue because form looks preserved.

The problem is not when reprojecting to lat/long and exporting that to shapefile.  It gets problematic when trying to export stateplane coords to shapefile.

Nevertheless I'll be more attentive to scales when reprojecting in M7x.

Thanks again.

---------------------------

Iván Santiago
Information Technologies
Office of Management and Budget <http://www.ogp.gobierno.pr/> 
787.977.9200 x 4289
Calle Cruz 254
PO Box 9023228
San Juan, PR 00902-3228
-66°05'07.25",18°26'54.74"(WGS84)
« De tous ceux qui n'ont rien à dire, les plus intéréssant sont ceux qui se taisent. » - Michel Colucci (Coluche)
« De todos aquéllos que no tienen nada que decir, los más interesantes son los que se abstienen de hablar»

________________________________

From: Bob Heitzman [mailto:rheitzman at gmail.com] 
Sent: Monday, May 07, 2007 7:07 PM
To: Ivan Santiago
Cc: manifold-l at directionsmedia.net
Subject: Re: [Manifold-l] Exporting to shapefile: Displacement

Works fine for Cal State Plane V.

Be sure to assign the proper projection to the TIGER stuff - looks like plane unprojected but the local scale is 0.001 (I think, a regular import via Manifold should be the correct scale. DO NOT change the scale in the assignment dialog after a fresh TIGER import. 

I occasionally get tripped up in that I export the TIGER layer as lat/long SHP files without reprojecting the data first. You must reproject the TIGER data to set the scales to 1 before exporting to lat/long. The scales=1 is needed so your layers play well with other non-projected layers. A similar scale issue could be your problem. The issue has to do with the poor support for projection metadata for shapefiles. 

On 5/4/07, Ivan Santiago <isantiago at ogp.gobierno.pr> wrote:

Greetings:

Does anybody's having problems exporting shapefiles using State Plane Coord System ?

It appears that sometimes the coords are multiplied by a factor, placing the exported shapefile hundred of miles away from their correct place.

My workaround is to project back the original (TIGER file) to Lat/Long (nad83), export that to shapefile and project the resulting file to SPCS NAD83

INFO:

Converting TIGER2006SE files from original source (census) to Manifold 7

Project chains drawing to State Plane NAD83 Zone PR & USVI (1) (What's the difference betw 1 and 2 anyways?)

Work with chains table, editing tabular data.

Export to shapefile (sometimes gives huge displacement errors) 

Manifold version: 7.1.16.1079

Intel Pentium Pro /II/III Model 5 Stepping 9

Physical Memory: 512 MB

OS: Win XP (b2600) SP 2

Running 32-bit mode

---------------------------

Iván Santiago
Information Technologies
Office of Management and Budget <http://www.ogp.gobierno.pr/> 
787.977.9200 x 4289
Calle Cruz 254
PO Box 9023228
San Juan, PR 00902-3228
-66°05'07.25",18°26'54.74"(WGS84)
« De tous ceux qui n'ont rien à dire, les plus intéréssant sont ceux qui se taisent. » - Michel Colucci (Coluche)
« De todos aquéllos que no tienen nada que decir, los más interesantes son los que se abstienen de hablar»

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