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.

learn more… | top users | synonyms (1)

23
votes
5answers
15k views

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

This may be very trivial question. To me they seems very similar in concept. What is the difference between feature class and feature layer?
15
votes
6answers
5k 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
4answers
317 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 ...
12
votes
3answers
6k 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 ...
10
votes
8answers
8k 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 ...
9
votes
2answers
308 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
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? ...
8
votes
1answer
5k 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. ...
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
1answer
2k 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 ...
7
votes
3answers
3k views

Z-index in OpenLayers 3: layer ordering in OL3

Is there a method to cjange 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 and I need to ...
7
votes
2answers
6k 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
365 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
2answers
238 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
594 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
453 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
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 ...
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
306 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
3answers
263 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
2answers
2k 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
3answers
9k 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
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 ...
5
votes
3answers
11k 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
2answers
2k 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.
5
votes
1answer
621 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
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
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
1answer
515 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
3answers
3k 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
189 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
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
4answers
1k 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 ...
4
votes
2answers
277 views

Layer just for annotations

Im relatively new to QGIS and would like to know whether or not I can save my form annotations to a layer so I can turn them on or off.
4
votes
3answers
662 views

Is there easy way to get layers names from WMS server?

I've been looking for information on how to get layers names from certain WMS servers, but I didn't find any. E.g. I have this server: http://sdi.geoportal.gov.pl/wms_prg/wmservice.aspx and I want to ...
4
votes
1answer
2k views

OGR and DXF files: Is it possible to handle layer names? (only “entities”)

I'm using Python and OGR to extract the layers of a DXF file and convert them into SHP. I began with: import ogr, os, sys driver = ogr.GetDriverByName('DXF') datasource = driver.Open('test1.dxf', 0) ...
4
votes
1answer
168 views

Is it possible to store a default symbology layer in an arcpy add-in?

Since arcpy is limited in how symbology can be manipulated, I was curious to know if a symbology layer can be stored in an arcpy add-in. Does anyone know if it is possible to store a .lyr file, or ...
4
votes
3answers
665 views

What Is The Ideal Workflow To Map (British) Postcode Territories

I'm looking for the best workflow for mapping postcodes and calculated territories, but being relatively new to mapping I'm struggling on a few details and also the best practices for displaying these ...
4
votes
1answer
812 views

Extracting donut holes as separate layer in QGIS

Does anyone know how I can extract the holes in a polygon layer as a separate layer in Quantum GIS? An example could be a country with a number of lakes cut out of the polygon - I need the lakes. I ...
4
votes
1answer
83 views

Automatically create new layers from a single dataset using definiton query for unique values in a field

I would like to automatically display a featureclass as different layers based on a specific field. I've seen a few tools online and on XToolsPro under the category of Split by Attributes, but they ...
4
votes
1answer
202 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 ...
4
votes
1answer
1k 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 ...
4
votes
1answer
69 views

QGIS 2 bold Layer names?

I am currently working with QGIS 2.0 in an Ubuntu environment. I have a quite large project with many different layers and layer-groups. By default the layernames are in bold fonts and the groups are ...
4
votes
2answers
4k 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 ...
4
votes
2answers
156 views

GIS projection for non-geographic data

I am working on two different types of data. One is related to mapping of Genome structure and another is creating a layout of the inventories inside Internet Data Center. What I am confused about is ...
4
votes
4answers
528 views

Why does the layer list context menu not open anymore?

I cannot access layers properties (i.e. change color, filter by query, anything). The mouse right click doesn't do anything. Is there a way restoring qgis to default? Ubuntu 12.04, QGIS 1.8
4
votes
1answer
64 views

Summarizing different (local) shapefiles/sources into one centralized database using ArcGIS for Desktop?

Using ArcMap/ArcCatalog 10.2, is there a way, to summarize a huge number of widely spread shapefiles/sources (different servers, different hard drives etc.) into one centralized database, in order to ...
4
votes
1answer
117 views

Comparing floor and roof areas using QGIS?

I am pretty new in this GIS topic and I would really appreciate if someone can help me with this problem. I am doing a research for university that shall show the available roof area for ...