A layer is a collection of information. It contains specific elements of a gis in a specific presentation method (e.g raster or vector layer). Layers can be edited separately in order to create individual toppics for a map.

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25
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5answers
18k views

What is difference between map layer and spatial dataset (e.g. feature class, shapefile)?

What is the difference between feature class and feature layer? To me they seems very similar in concept.
16
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6answers
6k views

How to improve rendering performance of very large shapefile?

I have a polygon shapefile that has a 100MB .dbf and 500MB .shp file component. The reason it is so large is it is a landbase classification for a whole district. Everytime I am viewing the file in ...
15
votes
3answers
7k views

How can I iterate over map layers in QGIS python

I'm having trouble figuring out how to iterate over map layers. I can access the currently highlighted layer in the table of contents via iface.activeLayer() but I want my code to operate on all ...
15
votes
4answers
338 views

Compare similar lines and update layers

Here there are two layers with the representation of the streets and the idea is: We want to update the most recent layer (with the red line) with some of the data storaged in the other one (the light ...
11
votes
8answers
10k views

How to georeference a vector layer with control points?

I have a non-georeferenced vector layer that I need to be georeferenced. With raster layers the task is easy and straightforward, but I have no idea what should I do with my vector layer. I have a few ...
11
votes
3answers
413 views

How many layers are too many layers in ArcMap?

I work on ArcGIS using a Citrix virtual software connection at work. It is dreadfully slow at times, and without any changes to the MXDs I'm working on, one minute ArcMap can be operating at a ...
11
votes
2answers
11k views

Changing data source path involving feature dataset in *.lyr files using ArcPy?

How can one change the source data paths for every layer file in folder X using arcpy? I've followed Updating and fixing data sources with arcpy.mapping as best I can, yet all I get is an unhelpful ...
10
votes
1answer
2k views

Sort layers in QGIS table of contents?

When I load a bunch of layers into QGIS from PostGIS, they seem to load in reverse alphabetical order. Is there any tools or plugins that allow you to quickly sort the QGIS TOC in a different order? ...
9
votes
2answers
411 views

How to refer to another layer in the field calculator?

Is there a way to select an attribute from a polygon layer and insert the value into a virtual field of a point layer using "within" in the field calculator? CASE WHEN within($geometry, ...
9
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1answer
6k views

Use python to add layers to TOC

I've been battling with adding layers to the TOC for some time now. I have managed to single layers added but need to loop through a folder and add all layers. Shapefiles I cannot get to add at all. ...
9
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1answer
1k views

Data Source of layer changing after copy/paste in Table of Contents of ArcMap?

I run into this situation all the time; I often just copy layers and groups of layers in the TOC of one Map Document and paste then into the TOC of another Map Document. For the most part this ...
8
votes
1answer
3k views

Can I change properties of several layers simultaneously?

I'm working on bulk data. I have a few hundred GeoTIFF images imported into a QGIS project, and I'd like to modify their layer properties - things like the no-data-value, transparency of certain pixel ...
8
votes
3answers
5k views

Z-index in OpenLayers 3: layer ordering in OL3

Is there a method to change Z-indexes of layers in OpenLayers3 like it was in old version? map.setLayerIndex(markers, 99); //set the marker layer to an arbitrarily high layer index I need to change ...
8
votes
2answers
8k views

Leaflet: How to move the layer-control menu?

This might be a silly question, but I could not find a documented way to achieve this. I'd like to freely position the layer-control menu, probably to the top left near the default zoom-in/out ...
7
votes
2answers
299 views

Displaying legend item as polyline instead of polygon in ArcMap?

I am using ArcMap 10.1 and am trying to create a legend that will display a polygon layer as a single line.
7
votes
2answers
7k views

Using Google Maps as layer in ArcMap?

Can I use Google Maps as a layer in ArcMap? Is it possible?
7
votes
3answers
4k views

Layer loadstart & loadend events in OpenLayers 3

OpenLayers 2 has these layer events "loadstart & loadend." What is equivalent to them in OpenLayers 3? While a vector layer loads and is rendered, I need to show a loading icon.
7
votes
1answer
2k views

How to perform a true GIS clip of polygons layer using a polygon layer in R?

I would like to do a true GIS Clip in R of soils polygons using a series of single boundary polygons, but I cannot find an R function to properly do it. It should work just like the CLIP function in ...
7
votes
2answers
2k views

How to copy a group of layers between QGIS projects?

In ArcGIS I am used to being able to have a couple of MXD documents open and copy-paste groups of layers from one MXD's table of contents to another. This can save a LOT of time ensuring consistent ...
7
votes
2answers
449 views

How to load a raster layer at the top of the QGIS ToC?

The following code inserts my new_layer just above the active layer in the QGIS ToC. new_layer = iface.addRasterLayer(...) Instead, I'd like my new_layer to be inserted at the top of the QGIS ToC. ...
7
votes
1answer
136 views

How to speed up QGIS project opening with large point datasets?

I recently loaded a big point set (in terms of memory usage) in the QGIS project i'm working on. This layer is necessary for the project but it is not used often. Most of the time is turned off. The ...
7
votes
2answers
244 views

Load third-party APIs only when the corresponding map layer is requested?

OpenLayers allows multiple map layers to be hosted on a common platform. If the map application supports a wide variety of maps, say from Google, Yahoo and Microsoft, I find that upon initialization, ...
6
votes
4answers
617 views

Is there a universal map/ layer format?

Just wondering if there is a universal map format that all GIS software can read. ie to quickly share layers with all our partner agencies which have different GIS Software, rather than have to ...
6
votes
1answer
489 views

Is it possible to have dynamic layer names in QGIS project?

I have a QGIS project with layers, based on PostGIS SQL queries that use current date. Since the data in the database changes, these queries return different data every new day. Is it possible to ...
6
votes
1answer
3k views

Delete layer from ArcMap using Python

Problem: I'm trying to loop through all my layers looking for layer named "CADAnnotation". If the layer exists then remove the layer from the mxd Notes: Running from Stand-Alone script (ie. NOT ...
6
votes
1answer
4k views

Programmatically adding shapefile to data frame in ArcMap? [duplicate]

I have a toolbox with python script which creates a shapefile from JSON txt file, but it does not show the generated shapefile in arcmap, i have to add it from the output location. What code shall I ...
6
votes
2answers
2k views

Can QGIS preserve layers when exporting a PDF? [duplicate]

I saw this posted about a year ago (Can QGIS preserve layers when exporting to PDF?) but figured it was worth asking again -- is this possible? My usual workflow with ArcGIS is to export to AI then ...
6
votes
1answer
73 views

Establishing Default Query layer for Google Earth in “Map to KML” export from ArcMap?

I export a lot of maps for customers who request them from our office. Recently I have seen more and more requests for us to export our GIS into the .KML or .KMZ file type so they can be viewed on ...
6
votes
1answer
413 views

Can I save an ArcGIS geospatial PDF with layers turned off, which can then be turned on individually in a pdf viewer?

I am working on an mxd that has many individual point layers (displaying species locations). To make life easy for my stakeholders, I'd like to export to a geospatial pdf so that all of these point ...
6
votes
1answer
1k views

How to add layer with ArcPy and retain feature class metadata (like Credits) in layer properties?

I have multiple feature classes in a geodatabase, each feature class has metadata including a Description, Credits, and other information. If I use the 'Add Data' button in ArcMap 10.1 to add one of ...
6
votes
1answer
658 views

Drive time analysis with ArcGIS Network Analyst?

What is the most common SETTING for the Layer Properties when creating time-travel polygons? I am in the process of creating 4, 5, 6 minute polygons using Network Analyst. Every time I generate ...
6
votes
3answers
292 views

Automating an ArcGIS Project that is a display of map

I'm relatively new to GIS and looking to automate a project. I have my 'base map' created in ArcGIS, but now need to create several hundred more so looking for an automated method to accomplish this. ...
5
votes
3answers
10k views

How to get the layer name?

I am using OpenLayers, Geoserver 2.1 CQL language. The problem is that I do not know how to address the layer. I am trying to call a function like this: var createWmsLayer = function(name, url, ...
5
votes
2answers
3k views

What is Python equivalent of ModelBuilder's Iterate Feature Selection?

My data consists of two featureclasses: Points = points representing trees Polygons = Polygons representing % canopy area by area. Each polygon in the FC has a % canopy measurement in the ...
5
votes
2answers
135 views

Move a layer in QGIS to a precise position based on centroid

I'm not quite sure how to phrase this so apologies if it is a duplicate. I have a project that uses a series of lines created from the boundaries of polygons overlaid onto a map in QGIS. I understand ...
5
votes
3answers
12k views

Change Icon of Single Vector Feature in Layer

Currently I am trying to change the icon of a particular feature of a vector layer that the user is focusing on. I add each feature to the map like so: var point = new ...
5
votes
1answer
660 views

MXD Performance - number of layers vs number of datasets

My mxd currently has 5 buildings layers accessing 5 different buildings datasets (one for each of 5 counties). Most often there would only be a single county's buildings in the current view, if that ...
5
votes
2answers
6k views

How do I add my own map layers to Leaflet

I have a Leaflet map and want to add two of my own small polygon layers (currently in shapefile format, but they could be converted to GeoJSON). Can this be done without a mapserver to publish them ...
5
votes
1answer
2k views

How do you symbolize a feature class layer in ArcMap 10 based on one attribute's value and then another attribute's value?

I currently have a point feature class that has a couple of attributes that I want to use to symbolize its layer. One of the attributes is called ExceedsTolerance, which either has "Y" or "N" for its ...
5
votes
1answer
413 views

Working with AutoCAD Layers in ArcMap

I am following the ArcGis10.0 desktop help to bring cad data into ArcMap but I'm having trouble accessing the Autocad layers set up in the Autocad file. I am: using the add data to reference in the ...
5
votes
1answer
1k views

what dictates the drawing order of overlapping features with in the same layer/feature class in ArcGIS?

I know that in ArcGIS drawing order is controlled by layers, and if I want to make some features be drawn on top of other features I can use definition queries to separate them into different layers ...
5
votes
2answers
3k views

Create multiple vector layers by reading a GeoJSON file once in OpenLayers

I am a begginner to OpenLayers, and my question is about making things more efficient. My work is about displaying time-dependent weather elements on several point locations on the map. All these ...
5
votes
3answers
4k views

How can I set the base layer of map before initialization?

I have been using map.setBaseLayer(layer); to switch to my preferred map layer, using the localStorage variable layer that is stored in my web browser, upon initialization of the map. But I realize ...
5
votes
1answer
207 views

How to convert PostGis Table (Grid data) to Continuous field using Qgis?

I'd like to transform my Gridded Layer (generated form a PostGIS table of points) to a continuous and colored layer. How could I do this with Qgis or any other program?
5
votes
1answer
2k views

Export each layer in map to a separate image

I have a mxd file with multiple layers I have to export to PNG/JPG. I would like to create a script which turns on layers one at the time before they are exported. So far I have come up with the ...
5
votes
0answers
98 views

How to speed up simultaneous working with PostGIS layers in QGIS?

we are working on one big layer at the same time (10-20 people). Some of us use QGIS 2.8.1 and the other 2.6. The user with 2.8 have a lot of crashes (QGIS). The 2.6 users don't have this crashes but ...
5
votes
0answers
149 views

Is there a limitation on the numbers of layers that can be displayed in QGIS?

I have been looking for an answer to this question for the last several weeks, so hope that someone here has encountered the same issue and has a viable solution to my problem. I am currently using ...
5
votes
0answers
48 views

What prior art can be cited to refute Apple's claim to have invented Interactive Map? [closed]

In U.S. Patent Application 20130339891 Apple Inc. claims "An interactive capability enables a user to dynamically adjust the content of an electronic map" as well as "Geospatial applications can be ...
4
votes
2answers
1k views

How to get layer type in OpenLayers 3?

I would like to iterate through all of the added layers in an ol.Map instance and only select the vector layers. So far I could get the individual layers with the a property of the resulting object of ...
4
votes
4answers
2k views

How to get vector data from OSM to use in QGIS?

How do I get data from OpenStreetMap which I can then edit in QGIS layer by layer? What is the best OSM output and what / how do I get to a suitable input for QGIS? OR...is there another appraach to ...