Frequently Asked Questions
Can Koop fetch more than 1000 records?
Yes. The Geoservices output plugin defines a default limit of 1000 records, but this can be overridden by using the
resultRecordCount query parameter. For example:
You can also access records beyond the first default 1000 by using the pagination parameters:
Can Koop reproject data to different coordinate systems?
By default, Koop has limited support for reprojection. The Geoservices output plugin includes an
outSR query parameter that allows for data requests in a non-WGS84 coordinate system. The value of
outSR can be a spatial reference ID or WKT. If a valid WKT is used as the request’s
outSR, Koop will use it to reproject the data. However, if the request’s
outSR is a spatial reference ID, only a few values will lead to successful reprojection - 4326, 4269, and 3857. This is because Koop uses the proj4 library which only includes default support for those three projections.
If you need to support other values of
outSR, you have a couple of options. If authoring your own provider, you can check incoming values of
outSR in the
getData method. If an unsupported value arrives, you lookup it’s WKT in something like proj-codes or a remote API like spatialreference.org, then assign the WKT as the value of
outSR. If you are using an already published provider, you can use the
after transformation functions to apply the same strategy. The usage section of provider transformation functions has a code example.
How can I disable Koop warnings from the console/logs?
You may see Koop related warnings in the console output. Most often these are related to an unset
idField that has an invalid value, or invalid GeoJSON. Note that invalid GeoJSON warnings may occur for any GeoJSON that does not conform to the specification noted by IEFT. Koop can work with non-standard GeoJSON (e.g., polygons with reversed winding are okay), so in many or most cases these warnings can be ignored. The warnings can be disabled by setting the
KOOP_WARNINGS environment variable prior to start-up:
> KOOP_WARNINGS=suppress node server.js