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15

Plotting the estimated slopes, as in the question, is a great thing to do. Rather than filtering by significance, though--or in conjunction with it--why not map out some measure of how well each regression fits the data? For this, the mean squared error of the regression is readily interpreted and meaningful. As an example, the R code below generates a ...


12

You might be interested in my slides from a SXSW panel on geotemporal visualization. While they don't cover every single approach, they do a pretty good job of offering examples for the most common approaches (note that many of these examples require a browser with SVG or Canvas support, so not IE<9): Showing time as a line on a map Showing time as map ...


12

The reason that you are not able to save Time related information in a shapefile is that the Shapefile format, does not support Time as an attribute. They only support Date fields. This is due to the fact that the shapefile uses an older specification of the dBase file (.dbf) to store the attribute table. If you need to store time data, you are going to ...


10

Uhm, you can work in PostGIS to give a better structure to the database. Create a table S (stations) with the following fields: StationID Location (a point that specifies the coordinates) Create another M (measurements) table with the fields: StationID MeasurementDT (date and time of the measurement) Value (measured value) Now, you can show all the ...


9

If you want to use Census tracts the good people at Brown University have already done the hard work for you: Brown University Longitudinal Tract Database This resource contains tract-level variables from 1970-2000 interpolated to 2010 boundaries, facilitating longitudinal analysis.


9

Expression to_datetime("Date_Field") + to_interval('10 hours') will add 10 hours to the "Date_Field". I have not tested fully, but it seems to_interval() accepts month(s) day(s) hour(s) and their combinations such as '1 day 2 hours'.


7

Specify local: true in your date formatting function: ${SALEDT:DateFormat(selector: 'date', local: true, fullYear: true)} Mintx's answer explains why you need to do this. More information on formatting info window/popup content is available in the help: Format info window content. Edit: Use DateString, not DateFormat to specify the local option: ${...


7

A shapefile of the TZ timezones of the United States Last data update: September 30, 2012 The tz_us shapefile captures the boundaries of the TZ timezones of the United States, as of TZ 2012c. The geometries are entirely derived from the countyp020p and timeznp020 shapefiles provided by the National Atlas. All the TZ timezones of United States listed ...


7

Your plan is fine. A traditional way to handing the "end date" is to leave it NULL, so every geometry has a start and end, and those that have been superseded have a non-NULL end point. Here's a very simple temporal model. http://postgis.net/workshops/postgis-intro/history_tracking.html If you're going to be doing a lot of temporal querying, looking into ...


7

When remote sensing vegetation, the time of year is very important. In most climates, vegetation has significantly more biomass (i.e., leaves etc.) during the summer, which means that it is easier for the sensor to discern the health of vegetation at that time of year. Two NDVI images of the same location from different times of the year may look different ...


7

Historical OSM data is available in the OpenStreetMap Full History Dump file. You can dowload it as *.pbf or *.xml data. Extracs of selected countries can be downloaded from http://osm.personalwerk.de/full-history-extracts/ or from http://odbl.poole.ch/extracts/. I recommend you the OSM-history-splitter to generate extracts out of *.osh files and the OSM-...


6

You could have a look at the Route360°-API, a pretty simple but powerful JS library which you can use with Leaflet (or even Google maps if you like). It adds travel time polygons to your map for the travel times you require (e.g. 10, 20, 60 minutes) and for the following travel modes: walk, bike, car, transit. There are quite a few examples on how to use ...


6

Yes, the CF 1.6 Conventions for NetCDF include the specification of collections of time series and it seems your data is similar to example H.2.1 "Orthogonal multidimensional array representation of time series": If you store your data this way, IDV should be able to recognize this as "point data". Hopefully more applications in the future will take ...


6

Yep, it is totally possible! Here are two examples with the same dataset, one is for changing intensity over time, https://team.cartodb.com/u/andrew/viz/32ff4f28-7e51-11e4-9555-0e853d047bba/public_map The second is more like you request (I think) and shows cumulative amount over time http://team.cartodb.com/u/andrew/viz/a0a551a0-9b41-11e4-856f-...


6

It's possible without using a python function, with a little bit of hacks: minute( age( todatetime('2000-01-01 10:18:00'), todatetime(2000-01-01 10:16:30') ) ) will return "1.5". To break it down, "age" returns the difference between two datetimes as an interval type. This needs to be wrapped in the "minute" function to extract the length of this interval ...


6

The current GeoJSON specification is geojson.org/geojson-spec.html and it defines "positions" as A position is represented by an array of numbers. There must be at least two elements, and may be more. The order of elements must follow x, y, z order (easting, northing, altitude for coordinates in a projected coordinate reference system, or longitude, ...


6

I don't think there is a way to do that for a particular date field, and this link provided by Get Spatial confirms it. However, if you turn on Editor Tracking, it will create fields for: Creation Date Creator Last Edit Date Last Editor You have the option to name these fields to whatever you want. So, you could call the Created Date Field "Date Notified"...


6

There is some detailed information here, on the ICSM page on datum modernisation. Note importantly the two stage implementation: Stage–1 GDA2020 The GDA2020 datum will result from a readjustment of the entire national geodetic network to a reference epoch of 1 January 2020. This will correct regional decimetre–level biases remaining in GDA94, ...


5

The new mosaic datasets are time-aware and can be published as image services (requires Image extension) Esri has a javascript sample , and if you look at the image service details you can see that there is a time extent along with the normal spatial extent, and even the Query operation supports time. This is definitely a neater solution (provided you have ...


5

Reproducing the map example you provided is primarily a cartographic effort and requires very little analysis if you have already calculated NDVI. I would use the following workflow to produce the map similar to the one you provided a link to. Collect the NDVI data to use in your analysis. In the example, they use "Summer" 1989 to 2001. In your case, you ...


5

Thanks for reply. I didn't know this log file. Really a great help! Here is the solution for my problem: http://myserver:8080/geonetwork/srv/eng/csw?SERVICE=CSW&version=2.0.2 &REQUEST=GetRecords&resultType=results &constraintLanguage=CQL_TEXT&constraint_language_version=1.1.0 &constraint=TempExtent_begin%20>=%20'2014-10-12T00:00:00Z' &elementSetName=full&...


4

I have had a little play around with your problem and have come up with a solution of sorts. Working with dates and times is always a pain and doubly so in ArcGIS as it has really limited support for these data types. I would love to see some other solutions to this problem as I am probably making this more complex than it needs to be. In SQL you could just ...


4

If you really need all the points for visualisation, then you can create a line and st_simplify (which is Douglas Peucker implementation) would do the job quite nicely. In some cases you do not even need to store all the points, so you could do filtering before saving point data, e.g. when subject does not move, do not store it. You can apply ...


4

I suspect that you might actually want a WMS rather than a WCS (since you say raster images rather that raster data, and are currently using Google maps). If all you want to do is display the images over time (using a slider or some such to control the time) then Openlayers and almost any WMS (GeoServer, MapServer, ArcGIS Server etc.) will handle this. ...


4

What you are describing is "Change Detection". There are many techniques for change detection using rasters. Probably the most common is image differencing where you subtract one image from another to produce a third. Though, it depends upon the type of data you are trying to compare. From your image, it looks like you're comparing changes in slope over ...


4

There is an ArcGIS add-on developed by the USGS Upper Midwest Environmental Sciences Center called Curve Fit: A Pixel Level Raster Regression Tool that may be just what you are after. From the documentation: Curve Fit is an extension to the GIS application ArcMap that allows the user to run regression analysis on a series of raster datasets (geo-...


4

Data sets like this can give very much information of course. I would do this in a spatial database environment, preferably PostgreSQL/PostGIS. What you want to do seems like a simple joining on both spatial and time data. Then you do everything in one query. The tricky part might be to optimize the indexes for the time joining. I guess the data sets is ...


4

The date_trunc works in PostgreSQL: # SELECT date_trunc('year', timestamp '2001-11-16 20:38:40' + interval '2 months'); date_trunc --------------------- 2002-01-01 00:00:00 (1 row) While in SQLite it gives the error you get: > SELECT date_trunc('year', timestamp '2001-11-16 20:38:40' + interval '2 months'); Error: near "'2001-11-16 20:38:40'...


4

Yes, the NetCDF CF Metadata Conventions version 1.6 specifies how to store point and station time series data in chapter 9 "Discrete Sampling Geometries". Since your data has the same sample times for all stations, I agree with Rich that you can base your netCDF structure on the example in section H.2.1 "Orthogonal multidimensional array representation of ...


4

You need to edit the properties of yours fields Date and Time in QGIS. Go to the properties of your layer. Select the Fields tab. In the line of your field (date and time), click on Line edit. Select Date/Time. And then you can specify the format of your date or time -> it must be the same as defined in Qt Designer! If the properties are the same in your ...


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