[Geomoose-users] map-source; only 2 valid types?
Brent Fraser
bfraser at geoanalytic.com
Tue Sep 29 13:21:04 EDT 2009
Brian,
That would be great!
One thing I noticed with my scale experiments is a potential problem with the
measure tool with projections (like Mercator) that have a wide varying scale
factor. A standard Mercator (with latitude of true scale of 0, the equator)
has a scale factor of about 0.6 at 54 degrees of Latitude (e.g. Edmonton Alberta
Canada). That means that an object with a length of mile (e.g. a Section line)
will measure 0.6 miles with the measure tool. While changing the Latitude of
True Scale (or the scale factor k0) will minimize the problem if you can limit
your mapping to about 10 degrees of Lat, it's not a solution to mapping the
world and wanting to measure small distances.
The solution would be to have a function that would return the scale factor
at a given Latitude (or given lat and lon to make applicable to all projections)
and apply that to the distance displayed.
I don't know if/how OpenLayers handles the issue...
Brent Fraser
Brian Fischer wrote:
> Brent,
> I'm going to see if I can get funding to make it happen.
>
> The limitations are:
> - your application would have to be in the Google web Mercator projection
> - no printing
>
> The raster reprojection would not be possible. That only works for a WMS service and I have found it is not that accurate when zoomed to small scales. This also has a little hit on performance but not bad.
>
> Brian Fischer, CFM GIS Project Manager
> Houston Engineering, Inc.
> Phone: W: 763.493.4522 / M: 763.229.2734
>
>
> -----Original Message-----
> From: Brent Fraser [mailto:bfraser at geoanalytic.com]
> Sent: Monday, September 28, 2009 11:26 AM
> To: Brian Fischer
> Cc: 'Dan Little'; geomoose-users at lists.sourceforge.net
> Subject: Re: [Geomoose-users] map-source; only 2 valid types?
>
> Brian,
>
> I'd be interested in seeing Google Maps access implemented, and I'd be
> willing to give up printing the Google Maps layer if it meant I could view it on
> the screen.
>
> Looking through GM v2's main.js and OpenLayer's google.html example, it
> appears that adding a layer type of "Google" looks simple. But I'm concerned
> about the projection. Would it mean that my site would have to use Spherical
> Mercator as the view projection? Would Dan's recent enhancement of raster
> projection in OpenLayers be useful so I could set a view projection of UTM? Or
> would performance be a problem?
>
> Best Regards,
> Brent (the other Brent) Fraser
>
>
> Brian Fischer wrote:
>> Brent,
>>
>> These two layer types that are on my wish list to integrate into
>> GeoMOOSE, as well as Tilecache layer types. Maybe we could pool some
>> money together to have Dan implement them?? As Dan and I have talked
>> about this in the past the tricky part is whether you need to be able to
>> print these layer types to .pdf. That requirement would be a much
>> larger effort than just making them viewable.
>>
>>
>>
>> Dan,
>>
>> Met Council just released a new basemap AGS Rest API service for the
>> twin cities. See snippet from email below. Jessica did mention she
>> tested this and got it to work with OpenLayers. It's pretty nice and
>> sure would be cool to show it can be used in GeoMOOSE!
>>
>>
>>
>> *Metropolitan Council ArcGIS Base Map Services*
>>
>>
>>
>> The Metropolitan Council is making available two cached base map
>> services through ArcGIS Server./ /The Metropolitan Council base map
>> contains common data layers symbolized and shown appropriately for 10
>> scale levels; including roadways, water features, political boundaries,
>> Parks, trails, and land marks. The base map will be updated as
>> necessary to maintain current data - at least quarterly to allow for
>> MetroGIS municipality and road updates.
>>
>>
>>
>> These services are available for use in within ArcMap, in web
>> applications through use of Rest Services, and as a layer in Google Earth.
>>
>>
>>
>> * *BaseMap*: In Web Mercator Projection suitable for use in mashups
>> with Google Maps.
>> http://gis.metc.state.mn.us/ArcGIS/rest/services/BaseLayer/BaseMap/MapServer
>>
>>
>>
>>
>> * *UTMBaseMap*: Same Features and Symbology as BaseMap above, but
>> projected for UTM, better for use with other MetroGIS data.
>> http://gis.metc.state.mn.us/ArcGIS/rest/services/BaseLayer/UTMBaseMap/MapServer
>>
>>
>>
>>
>>
>>
>> *Brian Fischer,* CFM GIS Project Manager
>> *Houston Engineering, Inc.*
>> Phone: W: 763.493.4522 / M: 763.229.2734
>>
>>
>>
>> *From:* Dan Little [mailto:danlittle at yahoo.com]
>> *Sent:* Wednesday, September 23, 2009 9:56 AM
>> *To:* Brent Lund (ADM); geomoose-users at lists.sourceforge.net
>> *Subject:* Re: [Geomoose-users] map-source; only 2 valid types?
>>
>>
>>
>> Currently unimplemented. The reason is that the actual requests are
>> managed by GeoMOOSE and require full integration in with the catalog to
>> work correctly. This simply hasn't happened with those two types yet.
>> ArcGIS93Rest may take a while because I'm not sure anyone has a test
>> server for me to utilize.
>>
>>
>>
>> *From:* Brent Lund (ADM) <Brent.Lund at state.mn.us>
>> *To:* "geomoose-users at lists.sourceforge.net"
>> <geomoose-users at lists.sourceforge.net>
>> *Sent:* Wednesday, September 23, 2009 9:51:56 AM
>> *Subject:* [Geomoose-users] map-source; only 2 valid types?
>>
>> Is the documentation http://www.geomoose.org/moose/docs/mapbook.html
>> correct in referring to only 2 valid types (mapserver, wms). Are
>> other OpenLayers types valid (but undocumented)? In particular I
>> am interested in utilizing OpenLayers types Google and ArcGIS93Rest.
>>
>>
>>
>> Thanks,
>>
>> Brent
>>
>>
>>
>>
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