I think a more common approach is to get your point data via a WFS call
as GeoJSON and then draw it using javascript in the client. Using your
.svg as a marker, LeafletJS, OpenLayers, just about anything will draw
the marker, make only the footprint clickable and it scales at all levels.
If your data doesn't update, say, more than hourly, and you really want
to simplify production, save your point data (or any vector data) as
FlatGeobuf. Nothing more than a simple web server to host the .fgb
file(s) is required (sorry MapServer!). Also, your masterportal.js is
over 8MB, that's a lot of JS for the client to download.
I use the above approach with 10's of millions addresses and building
footprints. The clickable area exactly matches any building footprint
(polygon):
https://www.femafhz.com/map/33.823316/-117.919366/18/footprints,addresses?vw=0
Scott
On 11/15/24 14:36, Lime, Steve D (MNIT) via MapServer-users wrote:
Hi Lars: Hmmm… I see what you mean but I can’t think of anything easy
offhand. We’d almost want a TOLERANCE MARKER option where you’d create
dynamic features from the placed markers first and then query those
instead of the underlying points. Or perhaps allow tolerance to be
defined with a dx/dy or even a simple polygon in the case where a layer
is a point feature.
If you’re using PostGIS, I wonder if you could create a query-only
polygon layer from the point layer. That is, basically create a
rectangle from the point based on the map extent, size or scale and then
you query that instead – same attributes and everything working off a
derived geometry.
--Steve
*From:*MapServer-users <mapserver-users-boun...@lists.osgeo.org> *On
Behalf Of *Lars Baum via MapServer-users
*Sent:* Friday, November 15, 2024 3:52 AM
*To:* mapserver-users@lists.osgeo.org
*Subject:* [MapServer-users] Custom Click Tolerance Shape for GFI Requests
Dear MapServer Community,
we have faced an issue with the click tolerance for WMS GetFeatureInfo
requests when using custom map symbols. We use a custom .svg vector
image to display points in most of our maps.
As I understand it, the TOLERANCE parameter only defines a radius around
the point. Therefore the shape of the clickable area is always a circle.
This does not match our symbol at all and results in a bad user
experience. Essentially, only the very tip of the image is actually
clickable.
I have created a demo page for demonstration purposes. Please visit
https://koelngis.stadt-koeln.de/koelngis/portale/
mapServerClickTolerance/ <https://koelngis.stadt-koeln.de/koelngis/
portale/mapServerClickTolerance/> to experience this problem yourself.
* The layer with orange symbols is a WMS layer that demonstrates the
problem I described above. It is terrible to work with since most
users instinctively click on the white circle but actually have to
click the tip to get a GFI response. I have added an additional
point layer that shows the clickable area defined by the TOLERANCE
setting.
* The layer with blue symbols is a WFS layer that works perfectly fine
(since the click is handled client-side). This is the desired
behavior for WMS requests as well. We cannot always use WFS due to
client performance constraints.
We would like to configure the MapServer so that the entire shape can be
clicked precisely. However, we could not find this capability in the
documentation. Please let us know if it is possible.
Offsetting the symbol so that the white circle matches the clickable
point is not an option because then the tip would indicate that the
feature is at a different location.
If it is in fact not possible and any commercial service providers are
reading this mailing list:
Feel free to send me a quote to opensource-mapser...@larsbaum.slmail.me
<mailto:opensource-mapser...@larsbaum.slmail.me>. We would like to pay
someone to contribute this functionality for .svg vector images to the
MapServer open source project.
For reference, this is how we configure the symbol in the mapfile:
SYMBOL
NAME "droplet"
TYPE SVG
IMAGE "../svg/dropletShape.svg" # You can grab
a similar .svg file from the website linked above.
ANCHORPOINT 0.5 1 # Make sure the tip of the
shape is centered on the point
END
# …
TOLERANCEUNITS pixels
TOLERANCE 10 # Radius of the clickable circle around the point
CLASS
NAME "Some Name"
STYLE
SYMBOL "droplet"
SIZE 40
END
END
Thank you very much for your help!
Yours sincerely
Lars Baum
GIS Developer
City of Cologne - The Lord Mayor
Office for Information Processing
Competence Center Geoinformationsystems
Auf dem Hunnenrücken 3
50668 Cologne, Germany
Mail: opensource-mapser...@larsbaum.slmail.me <mailto:opensource-
mapser...@larsbaum.slmail.me>
Note: I'm using an alias mail to protect my business mail account from spam.
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