Category: PostGIS

Database, PostGIS, SQL

The PostGIS learning Curve: ST_Within and ST_Crosses

In an earlier post, I was frustrated with the intersection of a polygon and line datasets coming out as a geometry collection instead of a simple line dataset as expected. Nicklas Avén was kind enough to point out that this is a natural consequence of the logic of an intersection, the definition of ST_Intersects is: Returns TRUE if the Geometries/Geography “spatially intersect” – (share any … Continue reading The PostGIS learning Curve: ST_Within and ST_Crosses

Unknown's avatarsmathermatherLeave a comment
Database, PostGIS, SQL

Geometry Collections and Small Headaches

The disk that held the personal geodatabases of our contour datasets died a while back, but not before I loaded the contours into PostGIS and started serving them up. Our new intern is working on putting together some shapefiles layer groups in ArcGIS for map production, and asked for a missing one… . I don’t have it, but in principle can always extract it from … Continue reading Geometry Collections and Small Headaches

Unknown's avatarsmathermather5 Comments
GeoServer, PostGIS

Parcel Annotations in GeoServer (with some Maplex help) (cont. 1)

See the previous post for an explanation, but here’s the SLD we used for parcel labeling. Now remember– we got those rotation values from Maplex, so this isn’t a pure use of SLDs, but boy is it a long one anyway: <?xml version=”1.0″ encoding=”ISO-8859-1″?> <StyledLayerDescriptor version=”1.0.0″ xmlns=”http://www.opengis.net/sld&#8221; xmlns:ogc=”http://www.opengis.net/ogc&#8221; xmlns:xlink=”http://www.w3.org/1999/xlink&#8221; xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance&#8221; xsi:schemaLocation=”http://www.opengis.net/sld http://schemas.opengis.net/sld/1.0.0/StyledLayerDescriptor.xsd”&gt; <NamedLayer> <Name>Parcels Annotation</Name> <UserStyle> <Title>Parcels Annotation</Title> <Abstract>Symbolization for labelling of parcels</Abstract> <FeatureTypeStyle> <Rule> … Continue reading Parcel Annotations in GeoServer (with some Maplex help) (cont. 1)

Unknown's avatarsmathermather1 Comment
GeoServer, PostGIS

Parcel Annotations in GeoServer (with some Maplex help)

smathermather: We have a guest blogger today– Ramon, a bright and hard-working intern I’ve had the pleasure of working with for over a year.  If you’re looking for someone versed in Postgre/PostGIS/GeoServer/OpenLayers, Ramon’s been my rock as we’ve been building our internal system, doing everything from basic grunt work to esoteric trouble-shooting.  I’m trying hard not to fall on my face now that he’s moved … Continue reading Parcel Annotations in GeoServer (with some Maplex help)

Unknown's avatarsmathermather2 Comments
Database, PostGIS, SQL

Shapfile spatial indices and PostGIS dumps

Another short post… . I have in place a framework for maintenance of our boundary data that works really well. I feed an edited shapefile into the database, and PostGIS creates all the versions of the boundary that need created. The database then exports the managed data to shapefile so there is a database version and a shapefile version depending on need. When all was … Continue reading Shapfile spatial indices and PostGIS dumps

Unknown's avatarsmathermather2 Comments
Database, PostGIS, SQL

pgagent — when triggers are too much

This will be one of my shorter posts. pgadmin III allows for the development of scheduled tasks that run on your PostgreSQL database. As my PostGIS triggers have gotten more complicated, and since they run per transaction to keep ACID compliance, a big mess can be made by just updating a dataset (this is what vacuum is good for), and the time for inserts can … Continue reading pgagent — when triggers are too much

Unknown's avatarsmathermather1 Comment
Database, PostGIS, SQL

Multi-ring buffers in PostGIS

I maintain a lot of versions of our exterior property boundary layer for our park system for different purposes, e.g. this post.  What I’d like to include in this automatically managed dataset is a multi-ring buffer version of the dataset for the purpose of a careful mask with fade (also useful for showing coastal vignettes— oops, ESRI link), e.g.: So, first we buffer: And discover … Continue reading Multi-ring buffers in PostGIS

Unknown's avatarsmathermather1 Comment