[GLLUG] Re: PHP GD Question

[Sean]

Oh that is a good idea =) Couldnt you use GD fillToBorder() 
command instead of writing the recurse yourself? 

You would need to start off with a blank bitmap map, then you could do the 
fill, and then overlay the county name and % number in it, and finally add 
the Key wherever you have space left in the image. 

That actually wouldnt take very long or be to hard if you had a decent 
bitmap editor that showed you the positions of the pixels and the image 
didn't have leaky borders to begin with. 
 
The sql for the database will be the hardest, since you will want to do as
much as possible with the sql query ie leave the math OUT of php for speed
And depending on your dataset, you might seriously consider postgresql
instead of mysql. I have a gut feeling mysql isnt going to easily handle
the dataset nearly as easily or as efficiently as postgres will.



 On Fri, 16 May 2003, Thomas Alan Hearn wrote:

> Lee,
>   I have worked with GD and PHP as well as MySQL quite a bit, and I would 
> agree that it would most likely be easier to have predefined colored maps 
> for the counties of michigan.  Drawing shapes with GD around county borders 
> could be quite a gruesome task, however it is possible.  One way to do this 
> is to use a map with borders that are clearly white or black, and write a 
> script with GD that recursively colors in between two points, checking if 
> they have exceeded the white or black colors of the border.  Hope this 
> helps. 
> 
> Cheers,
> Tom Hearn 
> 
> 
> Ex Fed writes: 
> 
> > Hello Everyone! 
> > 
> > We use models to predict the possiblity of a plant disease or pest 
> > emergence.  This is based upon an algorithm that takes as input hourly 
> > weather information to include humidity, temperature and precipitation.  
> > It requires  seven days of data to calculate this probability. 
> > 
> > On a dynamic webpage, I want to display these percentages on the screen 
> > with a color legend and have the appropriate county on the Michigan Map 
> > colored corresponding to the statistical probability calculated.  I would 
> > like the user to be able to select past weeks to see the probability, but 
> > the default map displayed would show the probability of the past seven 
> > days. 
> > 
> > Does anybody out there know if it would be feasible to use PHP and GD 
> > somehow to color in individual counties on a State Map image.   The 
> > coloration would be determined values that were stored in a Mysql database 
> > or determined by an algorithm that worked upon the values in a Mysql 
> > database.  Unfortunately, these are not simple rectangles, arcs, squares, 
> > the counties are pretty complex shapes. 
> > 
> > Or would this be a lot of work that might be accomplished by use of a good 
> > GIS/mapping package?  Does anybody out there have any experiences with GIS 
> > with Linux / Mysql acting as a server/datasource, serving up dynamic maps 
> > in users web browsers? 
> > 
> > Appreciate your input, 
> > 
> > Lee Duynslager 
> > 
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