Questions tagged [filter]

To show, hide, extract, or remove particular data from a larger set, narrowing it down, or the specific criteria used to do so.

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7
votes
2answers
2k views

How to de-noise a DSM?

I have created a DEM, DSM, and nDSM from a LiDAR Point Cloud using SAGA-GIS. I extracted the appropriate returns from the point cloud, then converted to grid, and then closed gaps to fill in any ...
1
vote
2answers
2k views

Using sieve filter in ERDAS Imagine and/or ArcGIS for Desktop?

Where can i use a sieve filter for my supervised classification? Can i do it in Erdas Imagine or in ArcGIS? I can't find it anywhere.
13
votes
1answer
25k views

How to filter features in a layer?

I am trying to display certain features in a shapefile-based layer using QGIS. I have found the subset function in the properties panel, which does exactly what i want, but is too tedious given that I ...
4
votes
1answer
324 views

Selecting LiDAR return point type in LiDAR dataset with ArcPy?

I am trying to create a Digital Earth Model (DEM) using ArcPy under ArcGIS Pro 2, but I am running into some problems. I can generate a DEM within ArcGIS Pro by selecting only the ground points ...
4
votes
1answer
5k views

Filtering a raster by pixel value ? (Qgis)

I have downloaded Globcover data in GeoTIFF format. I want to create a new grid which only has values where the Globcover data (the only band in the TIF file) has one certain value (==190). Can I do ...
26
votes
2answers
13k views

What is the difference between != NULL and IS NOT NULL in QGIS filter expressions?

I have a shape layer with an attribute containing NULL values to which I would like to apply a filter for values different from NULL. Using the available gui for such query construction, one would ...
7
votes
1answer
3k views

How to apply a filter to multiple vector layers in QGIS?

I am trying to apply an attribute filter to multiple layers in QGIS at once. The filter is to be applied to .osm data brought in through PostGIS to QGIS. I have tried selecting multiple layers -> ...
11
votes
1answer
952 views

QGIS query syntax differs between attribute table and feature filter

Using QGIS 2.16.2, I can successfully select records from a shapefile attribute table using the following expression: left("start_time", 10) = '2015-08-01' Please note that start_time is a string ...
10
votes
3answers
4k views

Filtering out canopies and buildings from DSM to have a bare earth elevation

Can anyone suggest methods in filtering out trees and buildings from a DSM so as to come up with a reliable DEM? What I have is a grid from a LIDAR data (.tif file, with 1m resolution). I was going ...
8
votes
1answer
2k views

How to apply a Majority filter in GRASS GIS?

I was wondering if someone could help me write a majority filter for GRASS GIS. I have this map (see below) which I need to run a filter over to make the red areas a bit more dominant. I know I can ...
1
vote
1answer
1k views

Keeping only ground points (class 2) with lasground in QGIS 2.14?

I want to keep only the LiDAR ground points in a las file, using the lasground tool from LAStools within QGIS. In QGIS Chugiak (2.4) there used to be an option to "keep class 2", but I don't know how ...
2
votes
1answer
3k views

Passing selected polygon to INTERSECTS filter in a WFS request

In the code below, <ogc:Filter> <ogc:Intersects> <ogc:PropertyName>the_geom</ogc:PropertyName> <ogc:Function name="querySingle"> <ogc:...
2
votes
2answers
5k views

OpenLayers WFS protocol: work with filters if the protocol is defined out of layer constructor

follow question:wfs-load-feature-check the scenario is: i am trying to load a WFS layer, since it takes a while to load all features, I want to give user a notice while waiting for response. the ...
2
votes
2answers
3k views

LAS dataset to raster with ground points only [duplicate]

I'm trying to make a raster from an LAS dataset. I want to only use points classified as ground, but I can't figure out how to do this. What I've tried is: Create LAS dataset from 2 .las files. ...
6
votes
4answers
1k views

How to filter LiDAR data by scan angle?

I am looking to filter LiDAR data (.las format) by scan angle specifications (e.g. keep all points < 15). From a basic Google search, it appears that the libLAS library has the ability to filter by ...
12
votes
2answers
4k views

How to filter big datasets in Geoserver WMS?

Is there a good way to filter datasets with approx 50,000 features in Geoserver? I'd have to select between 100 and 200 features based on ids. These ids are different from the FeatureIds. Couldn't ...
5
votes
3answers
2k views

Limiting list values based on previous field in QGIS Forms?

Looking for assistance to set up appropriate configuration to enable drop-down lists values to be filtered based on a previous value. Basically, I have a 3-tiered categorisation structure to one of ...
4
votes
1answer
1k views

Geoserver WMS Filtering: Clipping geometry against a polygon

My data set is a series of multilinestrings representing roads. During a WMS GetMap request, I want to specify a polygon and display only the portions of those roads that fall within the polygon. I am ...
1
vote
1answer
2k views

DWithin WFS filter is not working

I'm new to GeoServer andI want to buffer an area around a point. I'm using a DWithin WFS filter but not getting any results. Please tell me the correct format to use DWithin. My GET request: http://...
10
votes
1answer
6k views

Problem with WFS filters (BBOX, INTERSECTS)

I'm trying to get a feature/features from a small area using the BBOX (or INTERSECTS) filter in my WFS query. I should be expecting only a small set of features or a single feature and yet the query ...
6
votes
1answer
3k views

How to filter wrong GPS readings?

I have absolutely no experience with GIS, it just so happens that one of the hobby projects I am doing at the local hackerspace includes tracking a model boat with a GPS... I hope this is the right ...
4
votes
1answer
2k views

Filtering Image in Google Earth Engine based on metadata

I'm trying to create a raster layer of the USDA NASS Cropland dataset using only certain crop classes. Is ee.Filter.inList only used for ImageCollections and not Images? It seems more appropriate to ...
4
votes
2answers
4k views

How to use paging in a WFS query?

I am running a GetFeature request against a WFS server which does not support to download all data at once. Can I use ogc:PropertyIsGreaterThanOrEqualTo to split the dataset into chunks at download ...
2
votes
1answer
6k views

WFS 2.0 with bbox filter and attribute filter

I am trying to get the following WFS GET request to work: wfs = "service=WFS&version=2.0.0&request=GetFeature", name = "&typeName=storeName:layerName", bboxFilter = '&bbox=' + bounds....
2
votes
2answers
989 views

Geoserver CQL Cross Layer Intersection Failing

I am having trouble forming a properly formatted CQL request using geoServer cross layer filer functions and was hoping others could assist. My request is as follows: http://localhost:8080/geoserver/...
1
vote
3answers
5k views

How to show vector features in OpenLayers after hiding it?

I did change some vector features style (through check-boxes) using style property : var features = layer.features; for( var i = 0; i < features.length; i++ ) { //features[i].style = { ...
0
votes
1answer
285 views

PDAL Reader.las and Writer.las warning: 'found invalid value of '0' for point's return number'

I am trying to read and write LAS (*.las) file using PDAL but getting the following warning messages by PDAL's LAS reader and writer for ASPRS LAS files. (pdal pipeline readers.las Warning) C:/...
5
votes
2answers
2k views

What is the best approach to using IQueryFilter.WhereClause in ArcObjects?

What is your preferred / best approach to using IQueryFilter.WhereClause statements in ArcObjects (e.g. when selecting features by attributes)? You need to check the source type (shapefile / personal ...
5
votes
1answer
2k views

How to set a spatial filter with Python/GDAL?

Is there a way with GDAL (Python) to set a spatial filter (bounding-box) on a raster before I process it? I want to read it as an array. BandReadAsArray(band, xoff=0, yoff=0, win_xsize=None, ...
3
votes
1answer
245 views

Filtering (lasfilter on) huge LiDAR dataset

My dataset is about 8.3 GB after loaded into R environment by using lidR package. Some points which have return number greater than number of returns need to be removed. With a small dataset, I ...
3
votes
2answers
2k views

Filtering a layer with attribute value from another layer in Qgis 2.18

I am pretty new to Qgis and a real beginner when it comes to working with expressions in Qgis. Maybe someone can help me with following problem: I have several Layers (like Building + House) and ...
3
votes
1answer
3k views

QGIS Filter layer by expression [closed]

Can I make the filter by the value that is obtained by the function? for feature in iter: name_dot = feature['name'] print name_dot expr = QgsExpression("\"name\"=name_dot") selection= layer....
2
votes
0answers
465 views

Between operator QGIS

I am using QGIS Essen version (2.14.1). I am trying to filter my data based on dates. I am wondering if the "between" operator exists like in SQL? I'm trying the following query but the results are ...
2
votes
1answer
528 views

Filter the Feature Layer parameter in Python Script Tool

I have a Python script tool where I have a parameter of type Feature Layer because I want to have the already opened layers as a dropdown list. I was wondering if there is a way to filter this ...
2
votes
0answers
145 views

How to filter legend by map content in composer with raster layers?

Does the "Filter Legend by Map Content" button in composer of QGIs 3.2 version work only for vector layers? It seems it's a bug reported in 2.18.x version and should be fixed for 3.x versions (https://...
2
votes
2answers
1k views

Avoid NoData after Focal Statistics Majority

I am currently working with some classified land cover rasters (containing 8 land cover classes) in ArcGIS 10.0. I would like to make them look smoother and have therefore used the Focal Statistics ...
2
votes
1answer
489 views

Filtering noise out from bare-earth DEM with terrace fields?

I have a 1m bare-earth DEM, derived from LiDAR data, representing a terraced landscape. For the sake of any subsequent use of the DEM (e.g., least-cost path, cost surface analysis, and the like) I am ...
1
vote
2answers
78 views

QGIS 3.4 feature filter maximum() does not work

I would like to filter a layer with the maximum value of field_a, grouped by field_b. I tried this expression: "field_a"= maximum ( "field_a","field_b") But it doesn't work (there are no more features ...
1
vote
1answer
2k views

Openlayers - Vector Layer - Combining hide/show features using style property

I am trying to filter vector layer features according to their attributes. I have 4 check boxes: type_1, type_2, shape_1 and shape_2 Note that I am using Extjs for interface. at beginning I could ...
1
vote
2answers
2k views

GeoServer where clause filter

I use PostGIS, GeoServer, and OpenLayers for GIS development. I simply reach from GeoServer to PostGIS table or view and show it with OpenLayers, but I need some filtering operation on my spatial ...
0
votes
0answers
636 views

QGIS smooth raster DEM [duplicate]

Possible Duplicate: Raster generalization - buffers in rasters, expand pixels? I have a 1m LIDAR DEM which I'm manipulating in QGIS. I'd like to smooth the DEM, such as by having each pixel ...
0
votes
1answer
416 views

How to find out if a WFS instance supports filtering via CQL?

I am considering using Common Query Language (CQL) to add filter parameter to a HTTP curl query which runs against a WFS server. I found out that GeoServer supports CQL via WFS. Can I tell from a ...