topic Re: Convert Lat/Longs to Blob/Shape-thing in Developers Questions

Convert Lat/Longs to Blob/Shape-thing

EricThomas3 — Fri, 09 Aug 2019 19:32:13 GMT

I'm trying to POST lat/longs to a database that feeds Portal. My GIS guy says I need to convert the lat/longs to a "Blob/Shape" as shown below.

1. What is this Blob/Shape-thing?

2. How do I programmatically convert Latitude and Longitudes to this Blob/Shape-thing WITHOUT using ArcGIS desktop or Python?

Is there an API / service somewhere that does this?

Thank you

Example:

Convert FROM

35.649783386

01012d1d003b2d1d0d0000000001000080ded0e3bd188098bb97e013003130310d040000c0050190d9493141a062da26da214841c0050190d9493141a062da26da2148410000000000408fc00000000000408fc03130300000040d413149d9900105c0414821da26da62a0413149d9900105c0414821da26da62a0c08f400000000000c08f400000000000

Re: Convert Lat/Longs to Blob/Shape-thing

JoshuaBixby — Fri, 09 Aug 2019 20:02:11 GMT

I really hope some of the terminology from your "GIS guy" was lost in translation and that he isn't saying "blob/shape" because that is sufficiently vague to mean many things and nothing. Ask your GIS guy what spatial format, specifically, he can work with if not text-based coordinates. Also, are you just working with points?

Re: Convert Lat/Longs to Blob/Shape-thing

EricThomas2 — Fri, 09 Aug 2019 20:08:26 GMT

Hi Joshua Bixby‌, thanks for the quick reply.
Yes, only points.

As far as I know, we work with whatever format this thing is:

Do you have any details on what exactly this is?

Re: Convert Lat/Longs to Blob/Shape-thing

JoshuaBixby — Fri, 09 Aug 2019 22:27:36 GMT

For starters, 35.649... isn't a complete coordinate, it is just a number. I have a hard time believing that long hex string is the direct translation of 35.649.... But beyond that, I am not going to start guessing spatial data structures. Your GIS guy really just needs to tell you what it is, and if he can't then he isn't really a GIS guy.

Re: Convert Lat/Longs to Blob/Shape-thing

EricThomas2 — Fri, 09 Aug 2019 22:30:38 GMT

Hi Joshua,

Do you know what the long hex string represents?

Is it a "spatial data structure"?

If so, where are these referred to in the ESRI docs?

Re: Convert Lat/Longs to Blob/Shape-thing

DanPatterson_Retired — Fri, 09 Aug 2019 23:14:59 GMT

It is Friday and the GIS guy could be messing with you

Re: Convert Lat/Longs to Blob/Shape-thing

EricThomas2 — Sat, 10 Aug 2019 00:01:34 GMT

We have good guys . Not worried about them messing with me. Do need to know what these strings represent and how I can convert Lat/Longs appropriately without using ArcGIS Desktop or Python.

Re: Convert Lat/Longs to Blob/Shape-thing

JoshuaBixby — Sat, 10 Aug 2019 01:51:18 GMT

Not to belabor the point, but why don't your GIS guys tell you what spatial data format that is? Why do you, or any of us, have to guess? There are numerous binary spatial data formats, so a simple hex string isn't definitive in terms of what format it represents.

As an example, take a coordinate for my hometown in WKT format: 'POINT(-92.139 46.807)'. That point in SQL Server in native Geography spatial is 0xE6100000010C9EEFA7C64B67474037894160E50857C0 while that same point in WKB format is 0x010100000037894160E50857C09EEFA7C64B674740.

Re: Convert Lat/Longs to Blob/Shape-thing

EricThomas3 — Thu, 15 Aug 2019 15:59:44 GMT

Ok. Looks like the spatial data format is: DB2 ST_Point format stored in a BLOB field.

So back to the original question: How do I convert Lat/Long text pairs to this format without ArcGIS desktop or Python?

Thank you

Re: Convert Lat/Longs to Blob/Shape-thing

JoshuaBixby — Thu, 15 Aug 2019 17:56:08 GMT

Knowing it is DB2 helps. All databases with native spatial types include a range of geometry constructors that support common spatial data interchange formats, e.g., WKT, WKB, maybe GeoJSON, maybe GML, etc.... You should not have to generate the native spatial blob itself, simply pass one of the common spatial data interchange formats to the DBMS geometry constructor. See ST_Geometry function - DB2 - IBM Knowledge Center .

Re: Convert Lat/Longs to Blob/Shape-thing

EricThomas3 — Thu, 15 Aug 2019 18:28:14 GMT

Thanks for the continued guidance.

Reading through the docs provided, I'm still unclear on how I would POST Lat/Long pairs as "...one of the common spatial data interchange formats to the DBMS geometry constructor".

Example:

The DB2 database has a REST web service that I can POST data to
LocID: 1234
Lat: 47.123
Long: -122.345
etc.

What happens when I get to this ST_Geometry-type column?

What do I feed it?

Is it a calculated column based on the Lat/Long columns?

Re: Convert Lat/Longs to Blob/Shape-thing

JoshuaBixby — Thu, 15 Aug 2019 18:35:44 GMT

If the DB2 database has a REST web service where you can post Lat/Long, and you are working with Points, what is the issue? The REST service should take the Lat/Long and convert it to the appropriate native spatial type on the backend.