Dear Muizudeen,
On Tue, 20 Jan 2009, Muizudeen Kusimo wrote:
I have done the following:
1) Converted my .jpeg files to .tif and run the gdaltindex program to
georeference them. It returned a .shp, .shx and .dbf files. But I don't have
any .tfw file yet. Please see output of GDALTINDEX below.
gdaltindex doesn't create a georeference to your raster, it is usefull if
you have many tiled georeferenced rasters.
You should get information about the coordinates of the corner of the
scanned map or coordinates for any visible point on your scanned map.
Than you may create the tfw file by hand (if the sides of the scanned map
are parelel to the coordinate axices it is simple). Or you can use GRASS
or gdal utilities to calculate the transformation between your image
coordinatesystem to the map coordinate system (e.g. UTM).
2) I tested my .map file with the shp2img utility and it generated a blank
(white) .png file for me. Expectedly, the same blank file displays as blank
in the browser (i.e. Ka-Map UI).
AFAIK if you have a raster without georeference then Mapserver will use
the pixel row and column number as coordinates. So now the extent sould be
0 0 1098 1696
or if the given extent in your map file are the corners of your map then
create the following georeference file (tfw)
----- start of twf file
4802.18579
0
0
-2684.334316
-2200000
3840000
------ end of tfw file
But I am not sure the resolution of your raster is so different in
northing and easting direction.
My new questions:
1) My maps were scanned from a paper map, does this affect my ability to
Georeference them?
No. But you need reference points on the map where the coordinates are
known.
2) How do I determine the Projection of the scanned map images?
Usually it is written on. The projection is not so important if all of
your maps use the same projection (coordinate system).
Best regards
Zoltan
Thanks.
GDALTINDEX OUTPUT (condensed):
==========================
C:\ms4w\Apache\cgi-bin>gdalinfo c:\ms4w\apps\test\tmp\pg19.tif
Driver: GTiff/GeoTIFF
Files: c:\ms4w\apps\test\tmp\pg19.tif
Size is 1098, 1696
Coordinate System is `'
Metadata:
TIFFTAG_XRESOLUTION=200
TIFFTAG_YRESOLUTION=200
TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
Image Structure Metadata:
COMPRESSION=LZW
INTERLEAVE=BAND
Corner Coordinates:
Upper Left ( 0.0, 0.0)
Lower Left ( 0.0, 1696.0)
Upper Right ( 1098.0, 0.0)
Lower Right ( 1098.0, 1696.0)
Center ( 549.0, 848.0)
Band 1 Block=1098x8 Type=Byte, ColorInterp=Palette
Color Table (RGB with 256 entries)
0: 0,0,0,255
1: 165,171,167,255
2: 255,197,98,255
3: 239,168,102,255
4: 206,150,75,255
.
. #removed to conserve space
.
255: 177,169,148,255
C:\ms4w\Apache\cgi-bin>
The test.map file I used:
=================
MAP
NAME test
STATUS ON
SIZE 1280 1280
EXTENT -2200000 -712631 3072800 3840000
UNITS DD
#IMAGECOLOR 255 255 255
IMAGETYPE JPEG
WEB
IMAGEPATH "c:\ms4w\apps\test\tmp\"
IMAGEURL "c:\ms4w\apps\test\"
END
LEGEND
TRANSPARENT TRUE
END
SCALEBAR
TRANSPARENT TRUE
END
LAYER
NAME "My Sample Location"
TYPE RASTER
STATUS ON
TILEINDEX "tmp\pg19.shp"
TILEITEM "Location"
END
END #MAP END
@Venkat
I hope my mail gives a clearer picture of my status for your further advice.
Thanks.
On Tue, Jan 20, 2009 at 1:04 AM, Rahkonen Jukka
<[email protected]>wrote:
Hi,
First of all your jpeg files need to be georeferenced. Jpeg files are most
often georeferenced with world files which are named as .jgw. Sometimes
they are named as .tfw, even that name is actually reserved for tiff files.
And Mapserver understands also world files named as .wld.
If your images are georeferenced you can continue to building one single
layer from all of your images. It is done with gdaltindex utility program.
Gdaltindex is building a shapefile that records the extents of all the
images to be indexed.
Third step is to make a new raster layer that is using the shapefile index
as a catalogue for finding the actual image files that needs to be opened
when user is requesting a map from a certain area.
This should be enough to show you images as a single layer. It would be a
benefit to know the projection where the images are because otherwise they
cannot be reprojected. And for optimising performance it may be good to
convert jpeg images to tiffs, but you can just start from jpegs and see if
you are happy with the speed.
In conclusion:
1. Check georeferencing and projection, gdalinfo program is a good help in
this.
2. Make tileindex with gdaltindex
3. Make a new raster layer in mapfile referring to just created tileindex
file.
-Jukka Rahkonen-
------------------------------
*Lähettäjä:* [email protected] [mailto:
[email protected]] *Puolesta *Muizudeen Kusimo
*Lähetetty:* 20. tammikuuta 2009 10:45
*Vastaanottaja:* [email protected]
*Aihe:* [mapserver-users] Need Help with Custom (Raster) Data as Input
Hello Everyone,
I am new to MapServer, however I am working on an application that is
similar to Google Maps albeit with my own custom maps.
The problem is:
1) I have several maps mostly in .jpeg format and would like to use them as
Data Inputs for this Web Application. I can't seem to get it done correctly.
Must I convert these maps to a SHAPEFILE i.e. .shp or what? If so, how do I
convert them?
My development platform is:
- Microsoft Windows XP
- Ka-Map
- MapServer (MS4W)
Thanks.
NB: I am re-reading the documentation for a solution.
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