[OpenLayers-Users] Tips for creating custom WMS base map?
Jennifer Strahan
jennifer at greeninfo.org
Thu Feb 15 14:57:52 EST 2007
Hello,
Does anyone on the list have any tips/ tricks to keep in mind when
creating a custom WMS base map? I'm converting a Mapserver
application to the OpenLayers interface and creating a Mapserver WMS
service (or set of services) based on my original mapfile.
I'm wondering what approach I should take to get the best performance
and have some questions. First, here are the basics of the base map
I'm creating:
Extent is entire state of California. I will have 10 zoom levels
from 1: 5M to 1:9,000. Layers include hillshade (90m, 30m),
waterbodies, protected lands, urban lands, detailed local roads,
major roads, highways, cities, county lines, campgrounds, hiking trails...
Some questions:
1. Would it be best to create a separate base map for each zoom
level and then use Tilecache to create cached tiles? One issue with
this idea is that if I use PNG24 output the file sizes are
larger. If I use JPEG, the sizes are smaller but the vector data
looks fuzzy.
2. Or, should I create two raster-only base maps (one for small
scale and one for large scale) and use conditions in OpenLayers to
turn on the vector layers at the appropriate zoom levels? The issue
with this approach is that the raster and vector data loads
separately and can be confusing to the user.
3. Are there other methods that I should consider? Which options
would yield the best performance?
4. If I create cached tiles, how can I determine how much server
storage space I need for all of the tiles?
Any suggestions would be much appreciated.
Thanks,
Jennifer
Jennifer Strahan
GreenInfo Network - 1996-2006: A Decade of Mapping the Public Interest
116 New Montgomery Street Suite 738 San Francisco CA 94105
PH: (415)979-0343 x306 Fax: 415-979-0371 Web: www.greeninfo.org
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