On Mar 8, 2008, at 8:07 AM, Nicolas Ribot wrote:
How do you plan to serve your data ? A map engine (perhaps MapServer)
and a web application ?
Hello Nicolas,
Yes, correct, initially a web server to web browser. I also might want
to someday make a standalone application that could be distributed on
CD or DVD. I also have the need to create maps in-house. Currently I
tile individual quadrangles that I have created together manually - I
need a more automated solution. My most immediate need is to create an
in-house solution, then an online solution, followed by a DVD/CD
solution.
I am not entirely sure if I will be using MapServer or a home-brewed
solution. I am leaning towards at least seeing if MapServer will work
for me before I develop something myself.
Do you actually need to store rasters into the database ?
If you only need to display them or serve them through webservices,
you could georefence them in postgis, storing their spatial extension
and file name, but not the actual image data (and some other
information you might find useful, like image dimension, date, image
category, resolution, etc) into a 'raster' table, then use your map
engine configuration to integrate this information into your
application.
We often do the following when serving rasters in a web application:
1. Create a raster table to hold filename, image's bbox, image's
date, etc.
2. Populate this table with a python script using gdal/ogr to generate
images' information (bbox, size, date, description, etc)
3. Eventually create views on this table to create logical groups of
rasters
4. In MapServer, define one or several layers referencing these views
and use these layers as tileindex in RASTER layers. MapServer will
then use postgis views the same way it uses shapefile tileindex.
You can then query all your geo data (vector and raster) using postgis
functions.
You can also easily create new views/mapserver layers on the raster
table.
You don't have to deal with TB of storage inside PostGIS.
Thanks for the information!
Sounds great.
I wonder how small I should mosaic the raster imagery. Does the size
of the mosaic tiles determine how coarsely the image can be panned?
For instance, if I tiled the imagery in 1000 meter blocks, would the
client be able to pan say 10 or 100 meters, or would they have to be
panned in 1000 meter increments?
PS. I can provide you with a simple python script that scans some
directories to find images and generates SQL queries to insert into a
raster table defined as follow:
CREATE TABLE rasters
I would like to take a look at it if you don't mind emailing me...
Thanks again,
Jeshua Lacock
Founder/Programmer
3DTOPO Incorporated
<http://3DTOPO.com>
Phone: 877.240.1364
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