It's been a while since I've played with Raster GIS data other than for a back drop but I once had to do something similar using false colored IR images for land use classifications. Originally I was using the old DOS based Idrisi, which even then was very powerful tool but still a bit clunky. Years later I ran into a project that required that I try to classify a raster image based on pixel values but I no longer had access to Idrisi or ArcGIS.
The work around that I managed to devise was using an off the shelf image editor, I think it was Paint Shop Pro by JASC at the time, now bought out by Corel. I opened the image and played around with the histogram tool until I was able to isolate the areas I was interested in. These days, the software gives you a little more control with the histogram tools, as so far as specifying pixel values beyond equalizing or stretching the histograms. Now I think they give you ability to split the image by various color channels as well (RGB, HSL, and CMYK). This process still requires that you have a relatively good idea of where your areas of interest are.
Once I had the image I wanted, I then did something similar to what Reinaldo recommended, which was I used a raster to vector tool like R2V (actually I think I used Corel's raster to vector tool, the demo version of R2V only worded on small images) and then registered it in MapInfo. Registering it was bit of a trick because the resulting image no longer had recognizable geographic features. Fortunately, the original was a geo-tiff image with an associated tfw file. I simply resaved my new imaged to the old name and was able to obtain reference coordinates from it: If the area isn't too big or complex you could probably just do a quick and dirty heads up digitizing of the raster.
At best, perhaps this process will give you an image that will enhance the mosquito breeding areas better and then use this enhance image and do what Reinaldo suggested. I agree with Reinaldo though, in that if this is something you are going to need to do on regular bases you might want to consider investing in a Raster/Vector GIS like Idrisi or ILWIS.
Regards,
Viktor Keenan de la Hoz - Senior GIS Technician
City of Phoenix - Street Transportation Department
Design and Construction Management Division
| "Richard Hoskins" <[EMAIL PROTECTED]>
01/12/2005 09:39 AM
|
To: <[email protected]> cc: Subject: [Maptitude] getting info from image files |
As far as I know image files in Mapt are just cosmetic. However I have a .gif that has colors in it, a grid in fact from which I need to extract the color info (the colors represent some habitat qualities where West Nile virus mosquitoes can breed. This is easy to do in Idrisi or Spatial Analyst, but I want to design an exercise using only Mapt for my spatial epidemiology class. Is there anyway to vectorize this image? Or does anyone have any brighter ideas?
Thanks
Dick Hoskins
From: Stewart Berry [mailto:[EMAIL PROTECTED]
Sent: Wednesday, January 12, 2005 7:58 AM
To: [email protected]
Subject: RE: [Maptitude] Re: image files
Hi Pam
Please see <http://www.caliper.com/maptpric.htm> for upgrade pricing. One
of our sales representatives would be happy to contact you by phone to
discuss this further if that would be of help.
Kind regards
Stewart
At 10:50 AM 1/12/2005 -0500, you wrote:
>Right, I understand that you would recommend upgrading to 4.7. My problem
>with that is there doesn't seem to be an "upgrade" price; all I can find is
>the price to buy the whole thing all over again.
>
>I'm a really small business and this is one of the most expensive software
>packages I own. But everything else I've ever purchased has an upgrade
>option, especially when it's a change from 4.6 to 4.7, and not a whole new
>version, like 5.0
>
>Pam Lardear
>Run River Enterprises
>http://www.runriver.net
>315-559-0526
>"Helping you find your Way"
>
>
>-----Original Message-----
>From: Stewart Berry [mailto:[EMAIL PROTECTED]
>Sent: Wednesday, January 12, 2005 10:13 AM
>To: [email protected]
>Subject: RE: [Maptitude] Re: image files
>
>
>Hi Pam
>
>I would definitely recommend upgrading to 4.7. Otherwise any image
>conversion software used may degrade the image.
>
>Stewart
>
>At 10:06 AM 1/12/2005 -0500, you wrote:
>
> >Hi Stewart,
> >
> >I have ver. 4.6; is there no hope for my jpg files? The company I bought
> >them from says it cannot offer tiff.
> >
> >I tried bringing the image file into a photo editor and saving it as .jpg,
> >and changing the extension on the world file. The graphics came in, at
> >close to the same location (at least it was on the map in the same area)
>but
> >the scale was no where near the same.
> >
> >Any hope?
> >
> >Pam
> >
> >
> >Pam Lardear
> >Run River Enterprises
> >http://www.runriver.net
> >315-559-0526
> >"Helping you find your Way"
> >
> >
> >-----Original Message-----
> >From: berry_stewarttrancad [mailto:[EMAIL PROTECTED]
> >Sent: Wednesday, January 12, 2005 9:51 AM
> >To: [email protected]
> >Subject: [Maptitude] Re: image files
> >
> >
> >
> >Hi Group:
> >
> >Maptitude 4.7 supports *.jpg files:
> >
> >The Joint Photographers Expert Group (JPEG) file format, named after
> >the committee that wrote the standard, is based on a mechanism
> >designed for compressing either full-color or gray-scale images of
> >natural, real-world scenes. It works well on photographs,
> >naturalistic artwork, and similar material; it does not work so well
> >on lettering, simple cartoons, or line drawings. JPEG handles only
> >still images (there is a related standard called MPEG for motion
> >pictures). Maptitude can use pictures and images stored in JPEG files
> >as layers in your map.
> >
> >JPEG is "lossy," meaning that the decompressed image isn't quite the
> >same as the original image. JPEG is intended for compressing images
> >that will be looked at by humans, because is designed to exploit
> >known limitations of the human eye; you are more sensitive to small
> >changes in brightness than to small changes in color.
> >
> >JPEG is a less-desirable image format than some others for two
> >reasons. It is slow to display, because the file needs to be reread
> >(starting from the beginning) each time a new portion of the image is
> >displayed. Formats such as ECW, MrSID, and TIFF are designed so that
> >portions of the image can be displayed by finding and reading only a
> >part of the file. Also, JPEG has a fuzzy appearance and limited
> >resolution, especially for large-scale display of map and other
> >images with linework and text. Formats such as ECW and MrSID provide
> >increasing levels of resolution as needed (to some limit) as you zoom
> >to larger scales.
> >
> >To use a JPEG file in a map with other geographic layers, it must be
> >accompanied by a JPEG/World (.JPW) file. This file contains
> >registration information for the JPEG image, and Caliper registration
> >information is added at the end of the file. The first time that you
> >open a .JPG file and its .JPW file, they must be in a folder to which
> >you have write access so that Maptitude can add the necessary
> >registration information.
> >
> >Stewart
> >
> >--- In [email protected], "Pam Lardear" <[EMAIL PROTECTED]> wrote:
> > > I just purchase an aerial photograph that I am trying to use with my
> > > Maptitude. It comes as a .jpg with a .jgw World file. Is there
> >any way to
> > > use this with Maptitude, or to convert it to the TIFF and TIFF
> >World?
> > >
> > >
> > >
> > > If not, can anyone recommend a good source for aerial photos that
> >work?
> > >
> > >
> > >
> > > This is from Terraserver.
> > >
> > >
> > >
> > > Thanks,
> > >
> > > Pam
> > >
> > >
> > >
> > >
> > >
> > > Pam Lardear
> > >
> > > Run River Enterprises
> > >
> > > http://www.runriver.net <http://www.runriver.net/>
> > >
> > > 315-559-0526
> > >
> > > "Helping you find your Way"
> >
> >
> >
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
>
>
>Stewart J. Berry (BSc, MSc)
>GIS Specialist
>E-mail: [EMAIL PROTECTED]
>Phone: 617-527-4700
>Fax: 617-527-5113
>Caliper Corporation
>1172 Beacon Street, Newton, MA, 02461-9926, USA
>Web site: http://www.caliper.com
>
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>
Stewart J. Berry (BSc, MSc)
GIS Specialist
E-mail: [EMAIL PROTECTED]
Phone: 617-527-4700
Fax: 617-527-5113
Caliper Corporation
1172 Beacon Street, Newton, MA, 02461-9926, USA
Web site: http://www.caliper.com
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