[GLLUG] Re: PHP GD Question
Thomas Alan Hearn
hearntho@msu.edu
Fri, 16 May 2003 12:41:01 -0400
The FillToBorder function should work fine, and I would agree that you
shouldn't do any math in PHP if at all possible, it runs very slowly.
Cheers,
Tom
Sean writes:
> 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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