It's called a choropleth map.
http://oobrien.com/2010/01/simple-choropleth-maps-in-quantum-gis/ is one
tutorial I found.
On August 1, 2016 8:07:11 PM EDT, Chuck Young <wylie1...@gmail.com> wrote:
>Thanks Jim! You are right a join! I now need to know how to get the
>to show the density by varying colors depending on the density. I know
>must be fairly simple bit I just don't have the key to it in my mind.
>Somethimes it can be rigth in front of me but I don't see it. So an
>example mite be good if anyone has a place in the manual or tutorial to
>point me to.
>On Mon, Aug 1, 2016 at 4:53 PM, James Keener <j...@jimkeener.com> wrote:
>> Beyond just PostGIS, postgresql is a much better database on most
>> than mysql.
>> If you have two tables, one with geometries and one with densities,
>> both need to have the same id somewhere. Once you have the join key,
>> can perform a join , not a union, to get a result set containing both
>> geometry and the density. You can use raw SQL in qgis, but I tend to
>> a view in the database based on the query and the qgis will treat
>that as a
>> table, more or less.
>> On August 1, 2016 7:35:18 PM EDT, Chuck Young <wylie1...@gmail.com>
>>> I have been using databases for years and have used QGIS since 1.8
>>> general mapping. I know it can use additional data attached to the
>>> geographic data via a union query to display lots of different
>>> have map areas where population density would be nice to display
>>> different background fill colors bases on that density. I just need
>>> of a boost getting the idea as to how to start and which way to go.
>>> I have been using the program with SpatiaLite database. Do I need
>>> tto the PostGis db? Most of my other data is currently in MySQL.
>>> Thanks for amy advice / guidance!!
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>> Sent from my Android device with K-9 Mail. Please excuse my brevity.
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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