Questions tagged [indexing]

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26 views

Finding neighbors of latitude longitude pair location

I have a list of points (more than a few million) defined by latitude and longitude. I want to find out the neighbors of each point. For example, I want to know for each point, what the nearest point, ...
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21 views

QGIS reindexes data? [duplicate]

I work on QGIS. Whenever I make a layer (1500 lines) that is stored on a PostgreSQL server editable, a process of reindexing starts and lasts for long minutes! What is the reason and how could I get ...
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1answer
92 views

Why do I get the exception java.lang.ClassNotFoundException while updating geomesa indices?

I have some tables in geomesa, such as MyFeature. I have to verify if it is possible to modify the indices. I'm trying the following instruction from CLI: geomesa-accumulo add-attribute-index -u ...
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45 views

PostGIS: Is it interesting to create an index on geom column and an alpha numeric field?

I would like to know if it's interesting to create an index on an other column than the geom one. In some cases, I would like to do spatial analysis. If not, I would like to analyse only attributes. ...
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1answer
56 views

Indexing to Open Data Cube not working for land cover map

I'm trying to index a clipped version of ESA's 2015 land cover map into an Open Data Cube instance. I've written a product specification yaml and a yaml for te actual product itself and it indexes ...
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1answer
429 views

Subset raster stack with logical indeces R

Is it possible to subset a raster stack by indexing on a logical vector? r1 <- raster(nrow = 100, ncol = 100) r1[] <- round(runif(ncell(r1), 1, 4), 0) r2 <- raster(nrow = 100, ncol = 100) r2[...
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22 views

How to index spatial objects? [closed]

“R-tree is useful to store spatial objects such as restaurant locations”. I see this sentence a lot of time in internet but I haven't found the good explanation on this. Can anybody please elaborate ...
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128 views

Resetting system index of feature collection in Google Earth Engine?

I am using the sample to repeatedly sample from an image and because I am sampling many times and merging the collections, the ids are coming like 1_1_1_1_1_2_8. I am pretty new to EE so I am not sure ...
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1answer
90 views

How R-Trees, R*-Trees can be used to index the Road Network?

I am trying to understand the Tree Indexing method of the Road network. In R-Tree the Minimum Bounding Rectangle is used to store the data points, but how it can hold the line segments of the Map? Or ...
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1answer
81 views

R: Annual composite based on the median: How to get the index of the original layer for each pixel?

What I want: I have a list of rasterstacks which are timeseries (300+ layers) for different bands. The timeseries are irregular, and therefore I want to create annual composites based on median ndvi. ...
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1answer
272 views

Generating map sheets and index page in QGIS?

I have a project in QGIS and would like to print it out in multiple pages. I know how to set the pages one by one (pages 1,2,3), but I would like to know if there is an easy way to do the index page ...
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1answer
120 views

Is it possible to take advantage of lowercase index on column using CQL filter on WFS?

I am querying a WFS housed in geoserver - the data itself lives in a postgresql database. I would like to run case insensitive queries against the WFS and see there is an option to specify ...
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3answers
305 views

How to speed up query performance with PostGIS data served up in GeoServer and OpenLayers?

I have published a table with @ 6 million polygons to geoserver, and have built a tool using the OpenLayers filter class to query the data. The performance is abysmally slow, often times not ever ...
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1answer
23 views

Edit specific indexes from a feature of Attribute Table QGIS [closed]

I have an attribute table with many columns. One of them describes a unique code. The column's name is "specialcode" and the column's type is String(254). I want to do the following: Sort every ...
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1answer
318 views

indexes to optimize ST_Contains and ST_Overlaps for geoms in two tables

I'm a programmer getting into the wonderful world of GIS. I just had a fun day optimizing queries (took one from 60s to 3.4s, and another from 38s to 1.2s). Below is the last query that I can't seem ...
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1answer
114 views

Changing The coverage Atlas layer

I created a coverage layer ( polygon) for an atlas. It contains rectangle polygons which define the boundary of sheets (somehow irregular indexing along my layer). when I print the atlas without ...
2
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1answer
520 views

Create shapefile from file.csv using python pyshp module

I followed the guide given here Automate the writing records from csv to shapefile using pyshp module. I follow this procedure and the code doesn't give me any error, but it doesn't produce any output....
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1answer
224 views

Build a polygon raster as indexing grid with SQL

According to the plugin Indexed Vector Grid which builds a polygon raster from shape bounds and name every cell as "A1, A2, A3 ...", I need a more advance solution, which I can use for hundreds of ...
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1answer
328 views

Feature Grid Layer to cluster features at higher zoom levels in Leaflet

I was wondering if there is a plug in for Leaflet which accomplishes clustering features within a grid layer. Similar to marker clusters this allows for rendering an abstraction of all features with a ...
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2answers
224 views

Why the indexes for the attributes are not being used when GeoServer asks PostGIS?

I am working on a WMS to publish data with GeoServer (2.11.0). Tables come from PostGIS (PostgreSQL 9.6). I have indexed geometries on the tables and i have also indexed attributes which are being ...
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2answers
266 views

Determining best neighbourhood search radius for Topographic Position Index (TPI) for predictive soil mapping?

I'm not sure how to determine the best input values for a search radius to create a TPI for the purpose of predictive soil mapping. Would this depend on the spatial extent of the area I wish to map?...
2
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1answer
235 views

How would I determine my search radius when conducting a Topographic Position Index in SAGA GIS?

When running the TPI tool in SAGA, I get this parameter-entry window: Under the section highlighted in the red box, what do these parameters mean? Do the search/neighbourhood grouping parameters mean ...
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1answer
411 views

Creating Topographic Position Index in SAGA GIS?

I am trying to create a TPI from a DEM tiff file in SAGA but keep getting the following result: I'm just not sure what I'm doing wrong.
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0answers
632 views

How to speed up slow performance on postgresql Postgis?

I'm using postgresql 9.6 as my database. It takes too much time than the query itself. The query take about 160ms which is not as good as the wanted performance. My query is like : SELECT DISTINCT ...
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2answers
248 views

What is GiST page size using PostGIS?

How can I check the page size (and maybe modify) of the GiST index in PostGIS? From the PostGIS documentation, I quote: "... GiST indexes support the concept of "lossiness" which is important ...
2
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1answer
98 views

ArcGIS: raster table only shows two groups of cells

I am working on the raster map below, which has 352 rows and 350 columns. When doing Data Management Tools->Raster->Raster Properties->Build Raster Attribute Table in ArcGIS 10.3.1 (licence ...
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3answers
11k views

What is the purpose of PostGIS on PostgreSQL?

PostgreSQL already supports spatial data types, operators and indexing. What does PostGIS provide exactly that made it necessary to exist as an extension to PostgreSQL? Why don't we all just use ...
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2answers
738 views

How can I solve the problem with the “Indexing data” window while editing?

When trying to edit a vector layer using node tool, i get constantly the next message: Normally it appears once at the beginning of the edition and then it doesn't show any more, but now I get it ...
2
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1answer
114 views

What permissions needed to add an index with a protected version?

Using arcpy and ArcGIS 10.1 SP1 (Build 3143) against an Oracle 11g enterprise geodatabase, I am trying to add an index to an existing attribute in an existing feature class: arcpy.AddIndex_management(...
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0answers
117 views

Determining Highest Position in QGIS for raster stacks with 10+ images?

I want to follow up on this question from last year Emulating ArcGIS Highest Position tool in QGIS? Here the question is if QGIS has a tool like the "highest position" tool in ArcGIS, where, in a ...
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1answer
83 views

Index Page with data driven pages

I am trying to create an index page using a customized index polygon featureclass that I created. Is there a way to do that without using the grid index features tool, which is more for set sized ...
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0answers
156 views

How to index mbtiles to speed up load time?

I have created a mbtile based on OpenStreetMap data with Maperitive using the command: generate-mbtiles file=Path\filename.mbtiles maxzoom=16 Loading the file in QGIS 2.14.0 and zooming takes 15-30 ...
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1answer
176 views

Running Gevel on PostGIS 2.0

I have found Gevel, a tool enabling the visualization of the content of the GiST indices in Postgres. In particular, I am interested to use it to visualize the RTree spatial index in PostGIS. Does it ...
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1answer
581 views

How to improve PostGIS raster query

I have this query SELECT data_type, data_time, model_name, ST_Value(raw_data, 1, 202,417) AS val_0 FROM data WHERE data_type = 'type_a' AND data_time >= '2015-12-06 00:00:00' AND ...
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2answers
836 views

Will .sbn and .sbx files (spatial index) speed up operations in GDAL/OGR?

I'm trying to intersect large datasets in OGR and python using SQL queries like ST_Intersects and ST_Contains. These operations run very fast in ArcMap but I'm designing a system to automate them, ...
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2answers
261 views

AddIndex_Management throws maximum open cursors exceeded

The following script is run to create indexes across all the feature classes within a particular dataset: import arcpy import os.path def listFcsInGDB(): for fds in arcpy.ListDatasets("FRED.GS*",...
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2answers
747 views

PostGIS: Strategy for fastest select by BBox with an ORDER BY polygon area clause. Cluster?

Update 2 (below) suggests 14% of the table geometries are stored out-of-line with the rest of the table records. This may be a useful clue. The Problem: We've got a table with appx 170,000 WGS84 ...
2
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1answer
1k views

Basic sp-gist indexing?

Please forgive a very, very elementary question. I am using a PostgreSQL 9.3.5 database, and one of the tables stores longitude and latitude. (These are two separate columns.) I would like to do ...
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1answer
159 views

Factors in computing scoring for place name searches, like Geonames

As part of the FULL response style, the GeoNames search API returns results like the following: <geonames style="FULL"> <totalResultsCount>510</totalResultsCount> <geoname&...
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2answers
132 views

What index to use in this situation

I am working with 3 tables with 3 x 500 000 rows. There is one column that gives each object a unique ID (UIDN), there also is a column with the geom data (the_geom). There also are some other columns ...
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1answer
2k views

How to build, store and index a road network from a digital city map

I'm totally new to this domain so my question may sound like a little bit silly…… I'm eager to know how to extract, store and index the coordinates of the road segments(edges) and intersections or ...
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5answers
1k views

How to improve performance when using ArcGIS cursors in Python with big tables?

I have a pretty big point feature class in a file geodatabase (~4 000 000 records). This is a regular grid of points with a 100m resolution. I need to perform a kind of generalization on this layer. ...
3
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0answers
372 views

Trajectory Indexing: How could I store and index the large trajectory dataset generated by cars' GPS? [closed]

I have a large trajectory dataset generated by cars' GPS. Since I will do some data mining work on them, I need an efficient way to store and index them. I read some papers about Trajectory Indexing (...
2
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3answers
694 views

How to create a constant numeration of ID (indexing) in an attribute table (ArcMap)

Is it possible to create a constant indexing (as a numbers) in an attribute table of the theme with many objects that manner that it will remain (will not change) during update of this theme? I found ...
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2answers
2k views

Does arcpy.SearchCursor function support field indexing?

Does the arcpy.SearchCursor function support field indexing? In the sample script below, can I sent my cursor to loop through the values in the first field by setting an index to search the first ...
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2answers
2k views

ArcGIS field calculator: VBScript get data from previous row

When using the field calculator, how do I get data from the previous row in VBScript? In Python I'd do something like this: for index, row in enumerate(rows,start=1): row[index-1] += 5 I'm using ...
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1answer
198 views

Alternative indexing methods for point set operations

It is common to use a bounding box spatial index to improve performance when working with a large number of features. Where operations are performed against individual geometries with a large number ...