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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21
votes
5answers
10k 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?
13
votes
6answers
2k 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 ...
9
votes
6answers
4k 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 ...
8
votes
2answers
3k 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 ...
7
votes
1answer
1k 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? ...
6
votes
2answers
822 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
444 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
157 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
3answers
207 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
1answer
1k 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 ...
5
votes
3answers
6k 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
834 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 ...
5
votes
1answer
508 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
3k 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 ...
5
votes
1answer
1k 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
2k 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
1k 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
131 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? Many thanks and best regards, ...
5
votes
1answer
929 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
46 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
3answers
5k 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, ...
4
votes
4answers
957 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
1answer
473 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 ...
4
votes
2answers
282 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
1k 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
123 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
1answer
437 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
59 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
131 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
3answers
347 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
127 views

How can I modify layer order with the QGIS python API

Typically, after a new_layer = addRasterLayer(...) that inserts new_layer before the active layer, I'd like to move it to the top of the table of contents. How to do it? I use an existing QGIS ...
3
votes
2answers
401 views

How display many layers from Geoserver in one map?

1) I publish 4 layers in Geoserver (planet_osm_line, planet_osm_point, planet_osm_polygon, planet_osm_roads). 2) Then I add styles (from sld styles) to the Geoserver. 3) Then I set this styles in my ...
3
votes
1answer
326 views

What open-source web mapping solution I need to use for this situation?

I will try to explain what I need to do. I have about thirty KML polygons. I need to put them on some satellite map. On the top of these layers (KMLs, satellite) there must go layer with roads. I ...
3
votes
2answers
151 views

Why might layer appear not to turn off in ArcMap?

I was called over to try and fix an issue with a coworkers ArcGIS software (ArcView 9.3.1 SP1, Windows 7) and couldn't fix it. When a certain layer is turned off in the table of contents it never ...
3
votes
1answer
195 views

Show alternating contour lines

Is it possible to show only every other counture line? And how do you do that? (Im new to QGIS Lisboa 1.8.0, but even newer to QGIS Dufour 2.0.1, but have used ArcGIS a bit a while ago, and also ...
3
votes
3answers
405 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 ...
3
votes
1answer
874 views

How to add a layer file to an ArcGIS map document programmatically?

I want to create a feature layer from a layer (.lyr) file and add it to my ArcGIS map document programmatically. I am using C# and ArcGIS. I have a layer file and a shapefile.
3
votes
2answers
59 views

Where to look for oceanographical/environmental data for the Arctic (Baffin Bay/Davis Strait area)

I am looking for oceanographical/environmental variables that are available for Baffin Bay/Davis Strait area over the time period of 1995-2011, however, I am not familiar with ...
3
votes
1answer
2k views

XYZ Layer in Open Layers has Missing Tiles

In Open Layers I'm having a missing tile problem where it generates a missing link icon and a pink background. I found several threads including this one saying to add this code ...
3
votes
1answer
70 views

Is there a way to know if an error occurred while loading a WMS layer, in OpenLayers 2?

First of all, I already asked this question in stackoverflow. I don't want to spam by asking again here. But I think the question fits better in gis.stackexchange. I am sorry for the replication. Feel ...
3
votes
3answers
134 views

How to speed up redrawing of layers (from shapefiles) in MXD? [duplicate]

How do I speed up the process of redrawing layers in a MXD? I have already tried reloading and indexing the layers. The layers were created from shapefiles.
3
votes
2answers
251 views

Access Stamen tiles flavors with OpenLayers

i'm using OpenLayers (v2.13.1) and would like to use Stamen Toner tiles as background. The example is simple to understand : http://maps.stamen.com/test/openlayers.html But i'd like to use the ...
3
votes
1answer
254 views

How to fix link between layer and shapefile in ArcGIS 10?

Does anybody know how to fix a link between shape file and layer file in ArcGIS 10? Every time I add layer file, there is a small exclamation mark next to icon and I have to define a source (path to ...
3
votes
1answer
516 views

How to hide some parts of an image layer with OpenLayers?

My Problem I'm currently displaying a layer image above a Google Maps base layer. I would like, when the user check/uncheck some checkboxes, that some parts of this image layer disappear, and the ...
3
votes
1answer
149 views

Export multiple layers in ArcMap 10.1 and change each layer's source to exported data

A client has requested the MXD and relevant data for a particular map. The file contains over 40 layers across multiple data frames and references multiple geodatabases and shapefiles. Is there a ...
3
votes
2answers
190 views

How to subsribe Web Map Service from GeoServer?

I have my shapefile inside GeoServer and I already published it as a layer. I am able to preview the layer under GeoServer web interface. Now, I want to subscribe / import/ retrieve the shapefile as ...
3
votes
1answer
470 views

Layer map plots on top of one another in R/ggplot2

I'm making a choropleth map in R/ggplot2. I have the colored part working just fine. This code p <- ggplot() + geom_map(data=c_1860, aes(map_id = GISJOIN, fill = AHL002), ...
3
votes
1answer
2k 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 ...
3
votes
1answer
3k views

How to set up a layer control using Leaflet?

I have been working on a mapping application using Leaflet. I am using a WMS on Geoserver to get my layers, which are overlaid on a cloudmade basemap. I tried to use the layer control on my map by ...
3
votes
1answer
272 views

List Elements or Datasets of a given Layer

I am sorry of this might sound like a noob question but I cannot find any answer from google. I used arcpy to do batch processing of Network Analyst - Make Service Area layer of thousand of stores. ...