Crunchy Data joins Snowflake. Read the announcement
Martin Davis
Martin Davis
PostGIS excels at storing, manipulating and analyzing geospatial data. At some point it's usually desired to convert raw spatial data into a two-dimensional representation to utilize the integrative capabilities of the human visual cortex. In other words, to see things on a map. PostGIS is a popular backend for mapping technology, so there are many options to choose from to create maps. Data can be rendered to a raster image using a web map server like GeoServer or MapServer ; it can be conv...
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Martin Davis
In a previous post we announced the CQL filtering capability in . It provides powerful functionality for attribute and spatial querying of data in PostgreSQL and PostGIS. Another important datatype which is often present in datasets is temporal . Temporal datasets contain attributes which are dates or timestamps. The CQL standard defines some special-purpose syntax to support temporal filtering. This allows to take advantage of the extensive capabilities of PostgreSQL for specifying qu...
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Martin Davis
provides access to the powerful spatial database capabilities of PostGIS and PostgreSQL via a lightweight web service. To do this, it implements the OGC API for Features ( OAPIF ) RESTful protocol. OAPIF is part of the Open Geospatial Consortium ( OGC ) OGC API suite of standards. In a previous post, we announced an exciting new capability for : support for CQL filters . CQL ( Common Query Language ) is another OGC standard that provides the equivalent of SQL clauses for web q...
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Martin Davis
The goal of is to provide easy and efficient access to PostGIS from web clients. To do this, it uses the emerging OGC API for Features ( OAPIF ) RESTful protocol. This is a natural fit for systems which need to query and communicate spatial data. The core OAPIF specification provides a basic framework for querying spatial datasets, but it has only limited capability to express filtering subsets of spatial tables. In particular, it only allows filtering on single attribute values, and it...
Read MoreMartin Davis
Martin Davis
My colleague Kat Batuigas recently wrote about using the powerful open-source QGIS desktop GIS to import data into PostGIS from an ArcGIS Feature Service. This is a great first step toward moving your geospatial stack onto the performant, open source platform provided by PostGIS. And there's no need to stop there! Crunchy Data has developed a suite of spatial web services that work natively with PostGIS to expose your data to the web, using industry-standard protocols. These include: • p...
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Martin Davis
A classic spatial query is to find the nearest neighbours of a spatial feature. Our previous post " Won’t You Be My Neighbor? Quickly Finding Who is Nearby " discussed this capability from a PostgreSQL perspective. The PostGIS spatial data extension to Postgres can also execute nearest neighbour queries with remarkable efficiency. In this post, we’re going to take a deeper dive into the Postgres and PostGIS internals to find out how this actually works. By the time we surface you will have...
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Martin Davis
In addition to viewing PostGIS spatial data as vector tiles using pg_tileserv , it is often necessary to access data features directly. This supports use cases such as: • display features at a point or in an area of interest • query features using spatial and/or attribute filters • retrieve features for use in a web application (for tabular or map display) • download spatial data for use in applications display features at a point or in an area of interest query features using spatial and/or...
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