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commented
9 years ago Add a specific layer buffer tool that selects features in one layer, buffers
them, and then can be used to select features in another layer (through
configuration this can be used as an abutter’s list tool)
MassGIS would like to provide a tool to generate an abutters notification list.
However, to also be able to provide a more generic buffer/select tool for
other applications MassGIS would like to design the tool to be configurable.
The following describes the workflow and requirements.
- This tool would be an additional tool on the toolbar to the right of the
Filter Builder tool (if shown).
- The icon should be a “buffer” type of picture. (A shape within a shape,
with the outlines being different colors perhaps.)
- The tool should be configurable to be active on two specific datalayers.
(Configurable by MassGIS in a config file, the user does not get to choose the
two datalayers). Note that the datalayers may be either SDE or shapefile
datalayers.
(“select datalayer”) - datalayer that the user will select features in.
Those features will be unioned if necessary and buffered to form a select shape
(“buffer result datalayer”) - datalayer that the select shape is applied
against to select features
Those two datalayers could be the same in the case of selecting a parcel and
wanting to select other parcels within 300 feet. Or they could be different
in the case of selecting a road segment and wanting to select parcels within 50
feet of the road segement.
- Similar to the Filter Builder tool once the user choses the tool the the
“select datalayer” and (“buffer result datalayer”) should be added to
the map if they are not already there.
- Ask the user the type of unit - provide drop down with the standard list from
the measure tool - miles, feet, meters, etc
- Ask the user the amount of unit - provide a box that only accepts numerals.
- Just like the Identify tool the user should be able to draw a box to select
features in the “select datalayer”.
- If the “select datalayer” is “out of scale” which would be indicated
by the yellow exclamation point the user should be told the same message as the
filter tool “not visible at scale”. (same identify code)
- If the “select datalayer” is “in scale” highlight the features in
orange as the identify tool already does
- If more than one feature (parcel) is selected let the user know if it is more
than X where X is a number configurable by MassGIS. Grey out a “Select”
button which would do the union (if necessary and selection of features in the
“buffer result datalayer”).
- Apply a filter query for the “select datalayer” (see below for more info)
so that unacceptable features are dropped before Union
- If more than one feature (parcel) is selected union the features using a
union operation (possibly in-browser, possibly using the GeoServer WPS server
at https://wiki.state.ma.us/confluence/display/massgis/GeoServer+-+WPS+-+Union)
- Buffer the selected feature (or geometry results of the unioned features)
using a buffer opreation (possibly in-browser, possibly using the GeoServer WPS
Buffer request
https://wiki.state.ma.us/confluence/display/massgis/GeoServer+-+WPS+-+Buffer+-+P
olygon+-+Quadrant+Segments)
- Display the buffered shape symbolized by a thin red outline with light red
shading (same as the select box that shows during a regular Identify)
- Submit a WFS query to calculate how many features would return. If > 500
features would return inform the user that there are > 500 features selected
which is too many to continue with the buffered selection process.
- If < 500 features would return, submit a WFS request using that buffered
geometry to select features in the “buffer result datalayer”, only
requesting the attributes in the configurable attribute list.
- Filter features in the output set based on the filter query for the “buffer
result datalayer”
- If the “buffer result datalayer” is the same datalayer as the “select
datalayer”, drop the original selected feature from the “select
datalayer”. (An abutter’s list of parcels within a distance from parcel A
does not need to contain parcel A).
Things that should be configurable in a toolConfig_buffer.js or other config
files:
- whether the tool is visible (show/hide)
- datalayer (“select datalayer”) - datalayer that the user will select
features in. Those features will be unioned if necessary and buffered to form
a select shape
- datalayer (“buffer result datalayer”) - datalayer that the select shape
is applied against to select features
Those two datalayers could be the same in the case of selecting a parcel and
wanting to select other parcels within 300 feet. Or they could be different
in the case of selecting a road segment and wanting to select parcels within 50
feet of the road segement.
- max features allowed to be selected in the “select datalayer”
(We do not want to let the user select unlimited features in the select
datalayer.)
- filter query for the “select datalayer”
In the case of parcels we don’t want the user to be be able to select and
then buffer on parcels that are POLY_FEE=”ROW”. (We want the user to
select parcels that are POLY_FEE <> “ROW”.) The datalayer will necessarily
contain some of these types and the datalayer will not be symbolized to show
the types so it will be difficult for the user to customize their selection by
being instructed to unselect. We would prefer to do this programmatically.
MassGIS will explain in documentation what is happening but does not want to
force the user to customize their selection. If the user has any
POLY_FEE=”ROW” in their set of parcels to buffer, drop them out before
doing the union. If the only parcel the user select is POLY_FEE=”ROW”
inform them that their selection “does not meet the criteria”.
MassGIS is using a spatial view called GISDATA.L3_TAXPAR_POLY_ASSESS which
drops out the majority of the water, road and rail features but some are still
included.
Original comment by Aleda.Fr...@state.ma.us on 22 Apr 2013 at 1:04
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Original issue reported on code.google.com by
Aleda.Fr...@state.ma.uson 26 Dec 2012 at 9:06