Re: [UMN_MAPSERVER-USERS] No reprojection done

[Apeksha Bhambhani]

hii,

It seems that you have a lot of knowledge about projections in the mapfile . Could you please help us out . We have a few basic doubts. Here's what we are doing ....

 

We are working on the LAMP platform. We are creating an interactive web application . Users will be provided with a map , on which they can make their own additions and deletions.For example , when a certain user wants to landmark a certain city .

Could u help us out with a few of r doubts .

 

 Firstly as the input to the Mapserver will be shapefiles , we will be creating our layers , (Eg. Point , Polygon , etc,) with the help of OpenEV.When the shapfiles are created in OpenEV (for e.g the points layer ) the points are saved on the basis of their line and column value  This input will be given to the Mapfile of the Mapserver , which willl in turn give a complete image comprising of all the layers. This map can then be displayed using Php/Mapscript.

 When the user enters a certain point , the point details need to be added to MySql.

 

We wanted to proceed step by step. Now , as we first need a base map ( on which the user will make his/her changes ) , which will be a raster image ( .png or .tif ). We have created a map file for this( the raster image as a raster layer) as follows:

 

MAP

 

NAME first

EXTENT 0 0 40 40

SIZE 600 600

IMAGECOLOR 200 255 255

SHAPEPATH "/var/www/html/data1"

 

WEB

            IMAGEPATH "/var/www/html/tmp/"

            IMAGEURL "/tmp/"

END 

 

LAYER

NAME "base"

TYPE raster

DATA "/var/www/html/india.tif"

STATUS ON

END

END

 

This is not getting plotted , what could be the problem ?

Also , what exactly is the use of extent , because no matter what extent we give for another mapfile to plot a simple rectangle , the size of the rectangle remains the same .

Is projection mandatory in the mapfile ? And how can it be used .

When the shapfiles are created in OpenEV (for e.g the points layer ) the points are saved on the basis of their line and column value  . Does this require the use of projection.How can these points be saved in their latitude/longitude values.

 We are unable to understand the use of Projection ...Plz can u help us .

 

Awating your reply ,

Apeksha
Ed McNierney <[EMAIL PROTECTED]> wrote:

Luiz  & Bengt -

 

I would expect that if Bengt is working with maps of Scandinavian countries, the difference between Plat Carree and Mercator should be noticeable (Mercator will "stretch" things north/south by quite a bit compared to a "geographic" or Plat Carree projection).

 

Bengt, are you sure you have a good PROJ installation and that MapServer is compiled with PROJ support (run mapserv -v and look for "SUPPORTS=PROJ")?

 

     - Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
[EMAIL PROTECTED]
(978) 251-4242

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From: UMN MapServer Users List [mailto:[EMAIL PROTECTED] On Behalf Of Luiz Vaz
Sent: Tuesday, January 17, 2006 12:46 AM
To: MAPSERVER-USERS@LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] No reprojection done

Well,

   it seems that there no perceptual changes each other:

# World Mercator
<54004> +proj=merc +lat_ts=0 +lon_0=0 +k=1.000000 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m  no_defs <>

# World Plate Carree
<54001> +ellps=WGS84 +datum=WGS84 +units=m  no_defs <>
# World Equidistant Cylindrical
<54002> +ellps=WGS84 +datum=WGS84 +units=m  no_defs <>

# WGS 84
<4326> +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs  no_defs <>


Best Regards,
Luiz Vaz

2006/1/15, Nilsson Bengt <[EMAIL PROTECTED]>:

Hi,
I've set up a WMS server with an initial singe layer to test reprojection. However , I can't get the projection to work. Whatever output projection i try I get the same geographical (4326) back. For example, when I make a WMS request  with  SRS=EPSG:54004 (Mercator) and bounding box in that projection I get an 4326-map back. I do not get any errors. Here is my map-file:

MAP
NAME WMS-test
STATUS ON
SHAPEPATH "shp"
IMAGECOLOR 255 255 255
FONTSET ../etc/fontset.txt

DEBUG ON
WEB
  LOG "/tmp/mapserv.log"
  IMAGEPATH "/srv/www/htdocs/ms_tmp/"
  IMAGEURL "/ms_tmp/"
  METADATA
    "wms_title"     "Test"
    "wms_onlineresource" "http://hhhhhhhhh/mapserv/wt?service=WMS "
    "wms_srs"       "epsg:9823 epsg:4326 epsg:54004"
  END
END

PROJECTION
  "init=epsg:54004"
END

LAYER
  NAME k92_strandlinje
  DEBUG ON
  METADATA
    "wms_title"    "k92_strandlinje"
    "wms_srs"    "EPSG:4326"
  END
  TYPE POLYGON
  STATUS ON
  CONNECTIONTYPE postgis
  CONNECTION "user=postgres password=xxx dbname=xxx host=localhost"
  DATA 'the_geom from k92_strandlin_polygon'
  PROJECTION
   "init=epsg:4326"
  END
  CLASS
    NAME "strandlin-pgx"
    COLOR 255 251 237
    OUTLINECOLOR 100 100 100
  END
END

END


/Regards Bengt

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